I do my decking narrow side up, but the grooves facing left. That way you get the strength of 6in of wood beneath your feet. It’s a little more expensive, and you need to use 9in screws to fix it, but the results are magnificent. The grooves to the left thing is just personal preference, and it is also true that more rain comes from the left, than it does from the right.
The decking has a right to choose, whether it points to the left or the right. Some may even wish to point to the east. You should respect the choice - get yourselves woke🙈🙉🙊
@neondemon5137 trust me I know. I had 2 decking areas for a number of years & the decking with the flat surface is less slippy. I'm not making it up & you're more than welcome to not believe me. Over the winter especially algi would build up in the grooves & made the decking into an ice rink where as the flat side must have washed off in the rain because it was never slippy. Don't care whether anyone believes me but I know for a fact its true. To be honest I've replaced all my decking with patio because decking sucks big time & doesn't last
@@neondemon5137The reason why the grooves provide less grip is because it has less surface area for your foot/shoe to grip onto, mountain climbing shoes are smooth for the same reason.
As a time-served carpenter, I would install the smooth side up. The reason is that excess dirst and moisture would get trapped in the grooves. It doesn't need me to say that mosture trapped to timber would encourage rot. This would reduce the life span of the timber product. People can install it however they like, but I'm all for durability and a longer lasting solution.
Hi Andy... ..a brilliant video on Decking, I tore out a slimy slippy deathtrap decking a couple of years after I moved into a second hand house. The decking was aesthetically beautiful and it was only around 7 years old. It was fitted grooves up and just like you speculated, the rainwater welled in the grooves and as for frosty weather..it would pass for an ice rink! Cleaning it was a disaster and treating it cost a fortune. When I did remove it, I found that some of the boards (flat side down) had rotted where they were fixed to the joists. I am thinking that in addition to an air gap facilitated with groove side down, that the inverted peaks on the groove side when mounted upside down will actually allow water to drip off rather than running under the board! I actually recycled the deckboards for various projects around the garden fitting some of them groove side up, and some groove side down...and 10 years on.. Guess what!..almost without exception all of the groove side up are now disposed of due to rot, and all of the smooth side up are still goung strong!.. So there you go! Cheers to Geordieland from Ireland... - A PS.. we share a pet hate..I think that rose cookies take the biscuit also.. 😂
also with the ribbed side up you are literally halving the surface area of the board that can make contact with your foot. I've often thought about that when slipping on the grooved decking at my parents. I feel sure part of the reason is the lack of friction caused by half the area of your foot standing over thin air
Interesting video Andy. As a handyman in Australia I get asked this question often and I will always say that my preference is definitely grooves down but that they are reversible. Although I have never agreed to fit a deck with grooves up. I totally agree with your slipperiness argument in that if you don't maintain it then there will always be an algae build up eventually. For me, joist tape is a must but I agree that it won't prevent trapped moisture, however it's the board that suffers and not the joist. Boards are easier to replace though. My main gripe is with cupping. Grooved boards leave you with no choice which way to lay boards once you've decided on, up or down. Therefore, if I can convince a customer to pay a little extra, then I like to use hardwood that is smooth on both sides, which means that I can always crown my cupped boards. All of this, of course, is just my humble opinion. 😊 Enjoying your content mate, Cheers.
@@romansnews2298 But why do the manufacturers bother in the first place then? Surely they could just not do the grooves and get more profit right? Is this a situation where people expect things to be a certain way, so they are made that way, even though it's suboptimal?
They also now have stock with grooves on both faces. But don't worry the grooves are different sizes, so we can still argue about coarse grooves under or fine.
SO here's the problem, if I was to do a decking project, I would first go onto UA-cam, then I would go to 2 channels I trust, that I know have done a video on Decking, Gosforth Handyman and Charlie DIY and well you do it in two different ways. I have a solution though, Mr Proper DIY needs to do a Decking video and break the tie.
Thanks for the video.👍 A weak argument would be that by having grooves down could allow a tiny amount of airflow between the board and joist which could potentially dry and extend the length of the decking board. (Maybe?- Moot point I think) Smooth side up helps stop water just sitting in the groves and has a better chance to bead off and dry. But as we all know any deck needs a fall (same as in a patio) so water can runoff anyway. As for slipperiness (is this a word 🙃) both will get slippery if not cleaned/pressure washed. Worth noting any decking will become like an ice rink when it becomes frosty. On old ships the term 'swabbing the decks' was done regularly which was to stop the wood getting slippery. Ships decking were always smooth. Maintenance is key. I always recommend pressure washing twice a year, Autumn and then in Spring and oiled once in the Summer when the boards are bone dry. OIL NOT STAIN!!! Top tip for oiling....Get a big square/rectangle bucket (Toolstation £4), fill with your oil, use 9'' thick pile roller. Dunk roller in the bucket, shake off excess and roll SLOWLY on boards, too quick and will splash everywhere. This way is soooo easy and quick. Use brush for edges. Keep those vids coming 👍
If you don’t have enough run off, or the grooves going int he direction of the run off , the grooves are just more surface area for water to sit in and slime grow . Wood will absorb water and grooves is just more surface area .
Cedar and redwood are commonly used in canada and the pressure treated wood is typically to a higher retention standard than the UK. That is to say the wood is more rot resistant. Also Canadians aren't stupid they know groves are more dangerous, textured stains or anti-slip treatments on smooth boards are used.
@@Britbabe53 Same thing here in the USA. I’m not saying that nobody has decks with grooves; but the vast majority of decks have boards that are smooth on both sides.
I’ve just finished installing a patio that’s only for putting pots and plants on. I took a lot of inspiration from yours and Charlie’s videos on the subject. I was planning on putting my decking boards on ‘groove side down’ as you’ve mentioned but after putting two boards on the base, one grooves down and one grooves up, I consulted the boss and she said it looks too boring with the flat side up and it looked just like planks of wood so we ended up grooves up.
Smooth side up 100%. I've done both in the past, smooth up lasts longer as water evaporates quicker and does not well in the grooves. It looks better and after 5 years installed is not slippery in the slightest. My Austrailian friend is amazed British put ridge side up, they are for air flow to dry under the boards.
The grooves increase friction when there is water on them. When you step on the grooves there is more weight per square cm of contact area, this pushes the water out under your feet and into the grooves. It's why Formula One cars use treaded tyres in very wet conditions, but smooth tyres in dry conditions.
@Paul-yh8km mine were lethal groove side up, as I said now that I've gone smooth and regular coatings each year there is absolutely no slippery part to the boards even when wet. In my opinion, they look much better too
@@thechumpsbeendumped.7797 They use smooth tyres in dry conditions and treaded tyres in wet conditions. Water acts as a lubricant, the tread allows the vehicle weight to push the water into the grooves and increase friction between tyre and track.
I feel better now. After your recent videos I thought I’d got it wrong for the last 40 years as mine is grooves up. Enjoy the weekend with your family Andy 🌞
When I lived in Australia the decking round the pool was grooves up, but when I replaced it I made it grooves down as it was nicer to walk on with bare feet and it was easier to maintain
To be fair Andy, I am from the UK but live for the last 11years in Sweden. Nearly everyone here has some form of decking over here and per capita more than the UK. I would say 90% of deck boards here are laid flat and albeit grove boards are available, non grooved boards on both sides are much more common. I can also tell you that the climate here as way harsher than Blighty and in all honesty we don’t go to the measures you have gone to in order to protect the decking. Yet my deck is around 8 years old and in excellent condition. Actually took up a few boards recently and was amazed how good condition they were in underneath but also the subframe. So in essence if they can survive harsh Swedish winters then you have no problems in the UK. 👍
We get a lot of rain and damp especially leading up to winter. Plus when shed loads of snow melt and I mean tons if it, my decking can be like a swimming pool.
@@thechumpsbeendumped.7797no ship is unsinkable. They made a choice not to build watertight compartments all the way to the top. Also bad decision to try and turn if they’d hit the iceberg head on they wouldn’t have sunk.
No. They are to increase friction when the surface has water on it. The reduced surface area that your feet are standing on at the top of the groove increases the weight per square centimetre. That pushes the water into the groove and increases friction between you and the plank
@@Paul-yh8km Form the Timber Decking & Cladding Association..... "Contrary to some people’s belief, the grooves are not intended to provide improved grip underfoot"
@@unheard128 From the same page. "Grooves are designed to channel water away from the deck..." The intention may have not been to improve grip, but if the manufacturers understood a bit of physics, they would know the grooves would.
@@Paul-yh8km You are wrong, they are designed to remove water from the deck but they are talking about the underside. The grooves decrease friction a great deal, much like a dry ski slope. I explain in more detail in a post above.
There is no age-old question here. The grooves are to dry the wood out and shrink the bottom first so that water runs off the top and to keep water from building up on the cross timber beams they're in contact with. Putting this kind of decking groves up is just begging to have to replace it 3x as often or more. On top of this you're also supposed to buy special out-of-square timber beams that also shed the water - nobody does that but its true. Ship-lap roofs occasionally also have a grooved face and it goes down as well, sometimes also with wooden shingles you'll find carpenter-roofers who know their shit who will try to always face rough or splintered or chipped surfaces down.
Interesting video. Thanks for sharing. Before the video I would have said "grooves up" but now I think you've convinced me. At this moment I'd say "grooves down". I'm looking forward to the test result in 3 years.
I installed plain decking in the feont of my house in Belfast away back in 1999 .and in the back i used deck boards because i had steps installed. You have that choice when buying decking. Plain decking or grooved. But we wouldn't buy grooved to put upsaide down. Ty hat would be extra cost for no reason. And its was about £1- £2 difference in length back then. So in the case of my back garden which was all coverwd and raised about £200.
I'm from Australia. Grooves go down to allow the contact surface between boards and joists to dry out. Decking boards that are smooth on both sides are also sold here and becoming the more widely available option - I guess because it's cheaper to produce?
As a non UK follower I now put any deck in grooves down. I built a deck with grooves up but after 5 years removed it and reinstalled it grooves down for all the reasons you detail in particular - slippery, detritus and discolouration - needed water blasting every 6 months. With the grooves down so much easier to maintain and no longer dangerous to walk on!
The groves increase the surface area of that side. Fix with the grooves down and the smooth side up in the sun helps keep the decking flat and not cup. The same applies to the recess in the backs of architraves and skirtings. Been doing it since Adam was a boy.
Yes, I hear the groves can reduces the chance of board bending and deformation, especially in Australia’s dry environment, 100% groves side down for me.
Grooves and saw tracks are common on the back side of skirting boards,it is supposed to make the wood more stable and less prone to cupping, groves downwards would help with this problem also
I spent a while considering the same went grooves down for a couple of reasons. 1) I figured grooves down will give a better surface in the dry nice also easier to clean and manage. 2) I went this way taking inspiration from the window sills in that water can traverse the complete bottom of the wood it must drop off after first groove.
My bet is reversible is simply their way of saying we don't care, suit yourselves and give us your money. I'm for grooves down, I'm an interior flooring installer for 35 years so not my trade but I see a lot of houses and many after some time has past since construction with them up they are often in aweful condition and usually far more slippery and if they have been stained (coloured not dirty) its patchy as the staining tends to wear off the top of the grooves leaving raw and further coats end up uneven. If the tops smooth and you ever need to repair it you have no profile to match and if you wanted to sand or plane it to remove a board cupping or twisting where you maybe stub your toe on or w/e you can without losing the grooves and ruining the look of the whole deck.
Only just picked this up 😞 - Mine's installed grooves down. We've had hundreds of years with wooden sailing ships and none of them required grooves to prevent slipping, it just needed to be kept clean with a bit of sand every now and then. So that's what we do, clean it that is not the sand 🙂.
Grooves down looks much better. From personal experience, grooves up on a deck that was not well maintained was a pain to clean and re-protect. I used a jet wash and for it to be effective, the pressure was too high that resulted in a fibrous finish (but clean). I then had to sand but hat is where the problem lies ... the grooves. I certainly wasn't going to sand in the grooves. Then the application of the protection - another pain. Had I seen this video before the decking was laid, it would have been smooth side up. Thanks for the video, I now know what to do in future.
I've been 'grooves down' for a few years now, having experienced how slippery these boards get with the grooves facing upwards, having to then clean and maintain them - those grooves only make it a greater challenge and for no benefit, in my opinion. In the Karate Kid, Miyagi's decking had no grooves and he never lost his footing. Daniel would've walked away, had he been required to scrub grooved decking! 😅 Here in the UK, we had a moderately 'damp' climate. As a carpenter, I'd only want grooves on the underside of timber so that water can drip away (weatherbars and sills, for example). As a nation, we're notoriously bad (I think) at maintaining our external woodwork. My next question would be, where does the trend for timber decking eminate from? A country or continent with a drier climate?
Er.. I guess it emanates from .....a desire to do something quick, easy and relatively cheap ..... !!! Lightweight materials... copes with uneven ground, slopes etc etc ....!
Thanks Andy, I agree it's mostly personal preference, and yes I think the large growth in the use of decking following popular TV shows is partly the reason people have strong preference in the UK ! I've done both for different projects, in fact I currently have two garden tables I made with decking tops and one is groove up and the other groove down, the groove up is treated with a spirit based fence treatment that I regularly re-apply and the smooth is treated with one of those non-slip deck paints so I'll be interested to see how they compare over the years ! Top take-away here is "If you like ribbed, then choose ribbed !"
Decking is cheaper that is why people do it probably 60% cheaper than a patio, you need foundation's for retaining walls, sub base, drainage and steps for a raised patio it will also last forever. Unfortunately decking only has a ten year life span before it starts to deteriorate , surveyor's don't mind having the paving the same height as the internal floor so long as you have a water break between the slabs and the door frame. normally install a blade drain to the soakaway. if your extension has a suitable DPM wrapped to the DPC you are all good. Not sure why your surveyor doesn't like patios at the same height as the floor level in my 40 years of running a construction company it has never been a problem, Decking is the cheap option !
Interesting video, I had always 'assumed' it was grooves up, but I don't know why 😂. I guess my question would be, what purpose do the grooves serve ? Are they decorative ? Grip ? Drainage ?
They increase friction when the planks have water on them. The weight of your body is only on the top of the grooves, that's higher kg/cm which will help to force the water into the grooves and increase friction. Think if car tyres. Treadless tyres are really bad in rain but brilliant in dry conditions.
I see you are wearing your cap with the peak facing forward. We need a poll: peak forwards or peak backwards! Sorry, joking aside, a very interesting video. I'd always assumed grooves upwards but had not considered the alternative.
Canada Checking In: I've never even SEEN grooves on a deck board. Smooth top and bottom is the rule here, unless you're looking at a plastic/composite board.
Same in Sweden, I've never seen decking boards with grooves before. Recently composite decking boards have turned up with grooves in them. I'm thinking that grooves up or down would be a pain with a couple of layers of packed snow on top or ice expansion cracking from below.
Top tip. You should look at Percy Hudson's in North Shields for your timber. Used them for years. Its an old family business, and their quality tends be be a cut above other suppliers.
Never thought about it before, just assumed the grooves went up. My parents have a grooves up which get very slippery when wet. I think the argument is that the grooves act as a gripping surface and the problem with a flat surface is similar to a sort of aquaplaning in a car. But thinking on this more, most people wear shoes that have their own grip so the only thing grooves up is giving you is 50% less wood for your shoes to grip on to stop you sliding. So I think if the decking is to be outside and used when it is cold and wet you are probably better with grooves down, but if it is only likely to be used when warm and dry, or is under cover, then it is just down to personal preference.
You will find it’s very slippery if smooth side up, especially if you leave leafs . In general the both sides groves planks are decorative side up and a smaller grove to allow the board to flex to screw down.
Always gone with grooves up for dry climate/under cover (stops water collection and rot) and groves down for wet areas giving less contact with framing and better air flow at frame contact.
Quite right. I got sick of cleaning the green slime off. And slipping on it, as it's grooves up. Wish it was done the other way. There's no extra grip in fact it's slipper as it stays wet all day, water in the grooves. And it's harder to clean. I put anti slip stuff on in the end, which was great, but it was harder to do with all the grooves.
I go with grooves down as i feel the damp under the deck causes expansion on the underside and curves the board, the grooves help to control the expansion when the top is in the warm air.
When I did my decking for a kids tree house I used the Wickes and B&Q youtube guides which showed decking being laid groove up, I only found out about the difference of opinion afterwards. Also I found with grooves up no issue of worrying about protruding screws as I screwed into the grooves But I do understand rather like the "extension" effect of the room to the deck
So, I spent over a decade working for an Australian Timber Research body, whose main purpose was to develop building codes for the use of both domestic and imported timber. When it came to decking and in particular grooved timber products the recommendation was to have grooves down so that moisture and debris would not collect in the grooves causing decay and failure of the decking material. Additionally, grooved timber always bypassed import duties of raw material as it was considered a milled value added product therefore economically equivalent to domestic products. That’s the Australian situation it’s got nothing to do with slippery deck but importing and market penetration.
I do wonder if the grooves are intended to assist with differential thermal effects? When exposed to sunlight during hot summer weather I anticipate that the upper surface of the boards will get much hotter than the underside. This differential thermal range across the depth of the boards may result in them arching upwards across their width, possibly causing splitting or slight lifting of the fixings. The grooves may therefore be intended to be installed upwards to enable better ventilation and distribution of the heat and thereby equalise the thermal temperature range across the depth of the boards?
I just laid composite decking for the first time which i got at Eurocell and i wish i had gone composite long ago. My back garden is very shady in the winter and my wooden decking was so green and needed a fresh staining each year. It cost a lot more but I think its well worth it. i laid mine grove down too as the groves up take a lot more cleaning.
The grooves are designed to reduce the contact patch between both faces of timber. The only contact with the upper side of the decking just contacts feet and furniture. The grooves act like water dispersal tread on a tyre, but rather than being forced out by pressure with a tyre, it’s the grooves and accompanying capillary action that allow the water contact to be vastly reduced and helped to escape.
The original boards only had one side grooved, Other boards with both sides grooved and words like "reversable" came about later after so many people fitted them INCORRECTLY and made it fashionable. The grooves are meant to go on the underside as they act much similar to a drip on a window sill (the groove on the underside). The water can only travel over the edge of the board up to the first groove then drops off. The water can only travel over the long edges of the board as the ends are mostly sealed with the edge boards. This results in the board drying out ofter rain much faster as water cannot travel to the centre of the boards, preventing rot, obviously, Fitting them groove up makes them slippery even with a small about of moisture (acting much like a dry ski slope) and helps a great deal in hold water for a lot longer on the surface and the underside, resulting in a short life span. Hope this helps.
I've yet to get past 4:51 but will finish it. The quick comment is why you ran the boards in line with the floorboard was probably because you wanted a smooth transition from inside to outside and if you laid the boards the other way round you would have had a step of varying height across the patio doors due to the fall from one end to the other to facilitate drainage.
Surely it takes a non-zero amount of effort for manufacturers to create those grooves. If they don't serve a purpose and it's to go flat side up... why do they bother?
I was told that the original reason for grooves in timber planks was for 'stress relief'. It stops the plank bowing. As this may be the case, it might make sense to lay the boards groove down because it was never designed to be aesthetic. Maybe with your experiment you could try a plank (same board) with no groove and grooved to see if there is any bowing.
Flat side up can see the real wood grain look after oiling. sometime can find the good quality profile with fine mall grooves on the surface and big groove on the under side, this give people a clear anwer.
I looked into this about twenty years ago when we installed our siberian larch deck, taking most of my advice from what was then called the Timber Decking Association (worth buying their guide for anyone about to design and build one- great advice on species/span tables etc.) Grooves are essentially a British development; at that time they were virtually unheard of in North America (where decks were ‘invented’ ) Grooves are commonly used where antislip is an issue, but predominately on materials which don’t support algae growth. I’d also suspect that grooves on one side may lead to timber bowing / cupping, but that’s a whole new discussion….
The grooves on top will trap more water then if they were on the underside plus they also get very dirty and grubby. I did hear that the grooves act like a drip edge so water running down the edges of the board and underneath will drop the moment they hit a groove
Andy, A cracking review. My main concern with groove up is that as you say it traps cr@p which promotes algae and mainly tracks water to the ends of the run or joints which seen to be a point of rot out as they see way more water. And if the deck is layed up n down (not a consistent drop) along the lengths it traps the water I'm a grooves down guy
You didn't mention manufacturers guidance much Andy - since you showed a piece of Arbordeck timber as your example I checked their 2024 installation guide out of curiosity - and it shows the boards oriented with the grooves down!
I disagree with the comments about fall. I live in Wales, and many of my stone paths slope visibly. They all get slippery even a month after a pressure wash. Of course the slope makes it more ski slope than ice rink! Must wear good soled shoes and boots and use the hand rail. Yes it was pressure washed in September (end of October now), do the old fashioned treatments work longer eg Algon and Jeyes fluid? My decking was laid grooves up and needs replacing due to rot. Didn't stop it being slippery, hard to brush out the detritus, smooth side up looks favourite for the new one. Looking forward to your next decking discourse, thank you.
Personally I can't be doing with decking . It's slippy when wet and frosty and a potential haven for Roland and his mates. But if I was going to, I would use composite. But it's all personal preference 😊
AUSTRALIA QUEENSLAND. I used Mixed Queensland Hardwood, smooth on both sides , but it is all mostly protected from sun and rain. Two decks, ,8m x 2m and 8m x 4m, patio is paved at 8m x 4m
I've got smooth side up and 2 years later defo made the right decision. I was told it might get slippy. I haven't once come close to slipping. Visually it looks much better. I've oiled it and it's way easier to clean smooth side up. Also, grooves down mean air gets to the joists. So an absolute no brainer for me.
You mentioned not building a patio because of potential issues with surveyors. This has spooked me as I have MS and plan to lay a patio about 10mm lower than DPM (with channel drains where it meets the wall) so that i can access my garden with my wheelchair when my legs don't work. I know that building regs are changing with accessibility in mind. Will that change what surveyors pick up on? My property is a bungalow with concrete slab foundations and no vent bricks. Does that change the equation? A video on accessibility might be interesting tbh. It's always a good thing to consider with projects.
I'm in a wheelchair and my dad is a chartered surveyor. Accessibility doesn't give a pass on building regulations, quite the opposite. You would potentially need drainage such as an aerated gutter if you were not using a floating deck as you stated. A concrete slab floor does make some difference. Things like the angle of your garden make a difference, too. The drainage would have to be adequate, if the garden is higher than your foundation you may have more difficulties and your water run off can't affect your neighbours or increase the run off onto a road. I have decking to pavers with a french drain under the decking with a upwards sloping garden. You shouldn't get spooked, you just don't want your house flooding.
@mandowarrior123 I live on a bit of a hill with the ground sloping away from the house on all sides. My garden slopes by about 30cm over about 7m so I'm not concerned about water coming into the property as I can slope the patio away by more than enough and the runoff will mostly go into the gravel in my garden apart from the path that goes to my back gate. In my research I've seen lots of people saying to leave a gravel gap of 100mm between the paving stones and the wall. The channel drain I was looking at was 115mm wide so I think that is adequate and easier for me to maintain and then I found a page on the NHBC website titled "accessible thresholds" where they say a 150mm splash barrier should be fitted "using an impervious wall finish or cladding" and so I think if I put in some kind of flashing to prevent the 150mm of bricks above the patio from getting wet from splashes then it might be okay as long as it's not something porous that would bridge the dpm. I wish there was an easy way to contact building control to ask for advice. The only way I can contact them would be to submit a plan and the most relevant category they have for my local council is "alterations upto £5000) which has a charge of £283! Edit: The NHBC thing was about balconies which makes more sense with the flashing/cladding thing so it isn't applicable. After thinking about it some more I think I could leave a gap of around 150-200mm between the paving and the wall with the edge of the patio supported by a couple of courses of brick and have a french drain between the patio and wall with the finish height of the pebbles are below 150mm from the DPC. I could then make some kind of bridging material out of wood or composite decking to cover the gap but allow for drainage. It's basically a scaled up channel drain but deep enough to avoid any issues with building regs.
I've been to two completely different properties, one with decking as a raised patio area and the other with decking as the flooring of a gazebo, someway from the house. They looked great but rats had taken up residence beneath and became a big problem. Just a thought! ❤ XXX Dect
My garden has 2 bits of decking with it laid both ways, both are as slippery as an ice-rink for most of the year. Any tips on how to make decking less slippery?
Grooves down you might think it makes it non slip it doesn't fitted upwards so it makes sense to put the groove down. The water sits in the groove and dirt as well wearing the wood down over time.
Just be careful when its frosty which go’s for all external wood flooring scaffolding etc anti slip coating might be a good ideal if you use it a lot in winter.
Good video Andy and I watched it all and gave it a like. But, I don't have a deck, can't see me ever having a deck so, I don't really care!😂🤣 That said, I answered grooves down on your poll. Cheers.
Hi Andy, It's just down to personal choice, I did vote grooves up, I just picked a side I chose that, no reason. Summer last year I gave my brother a hand laying his decking and he chose groove side up. It could have been worse it could be, A) Groove side up.or B) flat side down Your choice🤣🤣As always a great video take care
Use an extension to kill the popups. The whole groove thing depends on the kind of wood, whether it was treated, the size of the grooves and the way the wood was cut. Ordinary wood that is quarter sawn doesn't matter but you are unlikely to get that for decking.The harder the wood, the less likely it will cup. ''Cutting a piece of flat sawn oak will yield a plank that not only shows a significant flame - or cathedral - grain pattern on its face but also one more prone to cupping. Wood tends to cup in the direction opposite the bend of the growth rings. Due to the angle at which its cut, flat sawn oak will almost certainly begin to warp over time as the growth rings are set at such a low angle to the face of the board'' If you notice flooring for indoors, they will almost always specify which face goes up.
My sister had hers done grooves down. Because it was in a quite shaded area and the UK weather it always has thin slick algal layer on it which was absolutely lethal, Grooves down unless you're dry and unshaded or want a maintenance headache.
It was my understanding the grooves are to stop the boards cupping? But you omitted this in the video, and no-one seems to have mentioned it in the comments.
It would be interesting to now do another poll after the video. I would have voted up before (uk based), but now I would vote on “personal choice”, but I would personally prefer it down.
Andy, one question about dpc and deck height. I was under the impression that the dpc was 150mm higher than the ground to prevent it being breeched by splashback when it rains. Would you not get a breech of the dpc installing decking so high like with yours? (especially if there is minimal overhang)
I live in the UK. I had always assumed that the grooves were there to help with grip and reduce slipperiness. It had never occurred to me that having the smooth up would be a good idea. I assumed that there would be no point in going to the extra expense and time of having grooves, and then having them facing down where they would no be seen and serve no purpose. The idea that they would help improve ventilation on the underside seems unlikely; the grooves are far to narrow for that. Maybe they would help with encouraging water dripping off though. My recent experience with decking with grooves up makes me feel that grooves up is a bad idea. (This decking was not installed by me and is of unknown age.) My experience is that the grooves retain water and general gunk and make difficult and tedious to keep clean. In certain types of weather it is very or extremely slippery. In one area it has rotted so much that it now has holes. I do not have any experience with smooth decking, but I would guess that it would be easier to keep clean. My experience with flagstones is that they are *not* slippery, even if covered in wet moss. I was surprised how non-slippery they were, even when wearing footwear with pretty smooth soles. These were quite roughly textured, horizontal flagstones though; on a slope I would not be quite so sure though. If you have moss-covered flagstones that you like, I suggest you do not assume they will be slippery when wet: check this out before cleaning it off. If I ever am having installed a "decking"/patio area for myself I would never use wood, I would have rough-textured flagstones.
I'd have the grooves down so that the rats that live underneath have a nice decorative ceiling to their home. 😁
Laughed so much i had tears running down my legs.😂
@@bejay69 🤣🤣🤣
Decking is dreadful, full stop.
@@bejay69 😂😂🤣🤣👍
I do my decking narrow side up, but the grooves facing left. That way you get the strength of 6in of wood beneath your feet. It’s a little more expensive, and you need to use 9in screws to fix it, but the results are magnificent. The grooves to the left thing is just personal preference, and it is also true that more rain comes from the left, than it does from the right.
@@alundavies1016 Tried vertical? You need to dig a deep hole though
@ there’s always a bit more work!
I made the rookie mistake of installing them grooves to the right which lead to an aggressive badger moving into my home and stealing my wife
@ that can happen!
The decking has a right to choose, whether it points to the left or the right. Some may even wish to point to the east. You should respect the choice - get yourselves woke🙈🙉🙊
I have my groves down so it doesn’t trap water in the groves, and it allows air through were they are fixed to joists
I've done both & the grooves down is much better. Way less slippy with flat side up, easier to clean, treat or paint
Convinced. You win.
@@GrumpysWorkshop4 tried both ways definitely grooves up, less slippery as the grooves give at least some tread to prevent slippage
How can a smooth, flat surface be less slippery? It doesn't make sense.
@neondemon5137 trust me I know. I had 2 decking areas for a number of years & the decking with the flat surface is less slippy. I'm not making it up & you're more than welcome to not believe me.
Over the winter especially algi would build up in the grooves & made the decking into an ice rink where as the flat side must have washed off in the rain because it was never slippy.
Don't care whether anyone believes me but I know for a fact its true. To be honest I've replaced all my decking with patio because decking sucks big time & doesn't last
@@neondemon5137The reason why the grooves provide less grip is because it has less surface area for your foot/shoe to grip onto, mountain climbing shoes are smooth for the same reason.
As a time-served carpenter, I would install the smooth side up. The reason is that excess dirst and moisture would get trapped in the grooves. It doesn't need me to say that mosture trapped to timber would encourage rot. This would reduce the life span of the timber product. People can install it however they like, but I'm all for durability and a longer lasting solution.
@@robertharris8912 I’ve had mine groove side down . 16 Years still going strong . Easier to clean and treat .
How does a time-served carpenter not consider which way the grain is curved?
I guess you must use magical wood which doesn't warp.
Hi Andy...
..a brilliant video on Decking, I tore out a slimy slippy deathtrap decking a couple of years after I moved into a second hand house. The decking was aesthetically beautiful and it was only around 7 years old. It was fitted grooves up and just like you speculated, the rainwater welled in the grooves and as for frosty weather..it would pass for an ice rink!
Cleaning it was a disaster and treating it cost a fortune.
When I did remove it, I found that some of the boards (flat side down) had rotted where they were fixed to the joists. I am thinking that in addition to an air gap facilitated with groove side down, that the inverted peaks on the groove side when mounted upside down will actually allow water to drip off rather than running under the board!
I actually recycled the deckboards for various projects around the garden fitting some of them groove side up, and some groove side down...and 10 years on.. Guess what!..almost without exception all of the groove side up are now disposed of due to rot, and all of the smooth side up are still goung strong!.. So there you go!
Cheers to Geordieland from Ireland... - A
PS.. we share a pet hate..I think that rose cookies take the biscuit also.. 😂
also with the ribbed side up you are literally halving the surface area of the board that can make contact with your foot. I've often thought about that when slipping on the grooved decking at my parents. I feel sure part of the reason is the lack of friction caused by half the area of your foot standing over thin air
Interesting video Andy.
As a handyman in Australia I get asked this question often and I will always say that my preference is definitely grooves down but that they are reversible. Although I have never agreed to fit a deck with grooves up.
I totally agree with your slipperiness argument in that if you don't maintain it then there will always be an algae build up eventually.
For me, joist tape is a must but I agree that it won't prevent trapped moisture, however it's the board that suffers and not the joist. Boards are easier to replace though.
My main gripe is with cupping. Grooved boards leave you with no choice which way to lay boards once you've decided on, up or down. Therefore, if I can convince a customer to pay a little extra, then I like to use hardwood that is smooth on both sides, which means that I can always crown my cupped boards.
All of this, of course, is just my humble opinion. 😊
Enjoying your content mate,
Cheers.
@@romansnews2298 But why do the manufacturers bother in the first place then? Surely they could just not do the grooves and get more profit right?
Is this a situation where people expect things to be a certain way, so they are made that way, even though it's suboptimal?
How about being crazy and having your decking laid alternating grooves up and grooves down 😉
@@mattridler377
Side ways
They also now have stock with grooves on both faces. But don't worry the grooves are different sizes, so we can still argue about coarse grooves under or fine.
@@Margarinetaylorgrease now there's a real thinker
@@mattridler377 I did exactly that and also did it in a herringbone pattern from corner to corner. Looks mint.
SO here's the problem, if I was to do a decking project, I would first go onto UA-cam, then I would go to 2 channels I trust, that I know have done a video on Decking, Gosforth Handyman and Charlie DIY and well you do it in two different ways. I have a solution though, Mr Proper DIY needs to do a Decking video and break the tie.
He’ll use composite decking, then you’re really f****d 😂😂😂
I'd be contrary and look to see what the manufacturer of the decking board states
You'll have to do it alternating, up/down/up/down so :D
Thanks for the video.👍 A weak argument would be that by having grooves down could allow a tiny amount of airflow between the board and joist which could potentially dry and extend the length of the decking board. (Maybe?- Moot point I think) Smooth side up helps stop water just sitting in the groves and has a better chance to bead off and dry. But as we all know any deck needs a fall (same as in a patio) so water can runoff anyway. As for slipperiness (is this a word 🙃) both will get slippery if not cleaned/pressure washed. Worth noting any decking will become like an ice rink when it becomes frosty. On old ships the term 'swabbing the decks' was done regularly which was to stop the wood getting slippery. Ships decking were always smooth. Maintenance is key. I always recommend pressure washing twice a year, Autumn and then in Spring and oiled once in the Summer when the boards are bone dry. OIL NOT STAIN!!! Top tip for oiling....Get a big square/rectangle bucket (Toolstation £4), fill with your oil, use 9'' thick pile roller. Dunk roller in the bucket, shake off excess and roll SLOWLY on boards, too quick and will splash everywhere. This way is soooo easy and quick. Use brush for edges. Keep those vids coming 👍
@@Brighton939 we give the customer the option, they always pick grooves up haha
If you don’t have enough run off, or the grooves going int he direction of the run off , the grooves are just more surface area for water to sit in and slime grow . Wood will absorb water and grooves is just more surface area .
In Canada, I've never seen anything but smooth on both sides decking.
Cedar and redwood are commonly used in canada and the pressure treated wood is typically to a higher retention standard than the UK. That is to say the wood is more rot resistant. Also Canadians aren't stupid they know groves are more dangerous, textured stains or anti-slip treatments on smooth boards are used.
@@Britbabe53 Same thing here in the USA. I’m not saying that nobody has decks with grooves; but the vast majority of decks have boards that are smooth on both sides.
I’ve just finished installing a patio that’s only for putting pots and plants on. I took a lot of inspiration from yours and Charlie’s videos on the subject. I was planning on putting my decking boards on ‘groove side down’ as you’ve mentioned but after putting two boards on the base, one grooves down and one grooves up, I consulted the boss and she said it looks too boring with the flat side up and it looked just like planks of wood so we ended up grooves up.
EXACTLY........!!!!
Personal choice.........!
Smooth side up 100%. I've done both in the past, smooth up lasts longer as water evaporates quicker and does not well in the grooves. It looks better and after 5 years installed is not slippery in the slightest. My Austrailian friend is amazed British put ridge side up, they are for air flow to dry under the boards.
The grooves increase friction when there is water on them.
When you step on the grooves there is more weight per square cm of contact area, this pushes the water out under your feet and into the grooves.
It's why Formula One cars use treaded tyres in very wet conditions, but smooth tyres in dry conditions.
@Paul-yh8km mine were lethal groove side up, as I said now that I've gone smooth and regular coatings each year there is absolutely no slippery part to the boards even when wet. In my opinion, they look much better too
@@Paul-yh8km
When did F1 start using wooden tyres?
@@thechumpsbeendumped.7797
They use smooth tyres in dry conditions and treaded tyres in wet conditions.
Water acts as a lubricant, the tread allows the vehicle weight to push the water into the grooves and increase friction between tyre and track.
@@Paul-yh8km
That's not what I asked. 😆
I feel better now. After your recent videos I thought I’d got it wrong for the last 40 years as mine is grooves up. Enjoy the weekend with your family Andy 🌞
@@raydriver7300 fitted mine grooves up 20+ yrs ago. Still good.
When I lived in Australia the decking round the pool was grooves up, but when I replaced it I made it grooves down as it was nicer to walk on with bare feet and it was easier to maintain
To be fair Andy, I am from the UK but live for the last 11years in Sweden. Nearly everyone here has some form of decking over here and per capita more than the UK.
I would say 90% of deck boards here are laid flat and albeit grove boards are available, non grooved boards on both sides are much more common. I can also tell you that the climate here as way harsher than Blighty and in all honesty we don’t go to the measures you have gone to in order to protect the decking. Yet my deck is around 8 years old and in excellent condition. Actually took up a few boards recently and was amazed how good condition they were in underneath but also the subframe. So in essence if they can survive harsh Swedish winters then you have no problems in the UK. 👍
It’s the wet and damp not the temperature.
We get a lot of rain and damp especially leading up to winter. Plus when shed loads of snow melt and I mean tons if it, my decking can be like a swimming pool.
@@markgeezey1809 I imagine crisp cold winters are much better for decking then endless mild drizzle
@@nick6584yes I imagine the worst climate is a warm and wet one, i.e. ideal growing conditions for organisms.
“They built the Titanic there, I kinda trust their judgment...” I'm not sure that's as good a metric for good decisions 😉
Was sank on purpose to reset the banking system.
@@thechumpsbeendumped.7797 Ship was good, sailing not so and rescue failed totally.
@
Apart from it was supposed to be unsinkable, it also didn’t have enough lifeboats.
@@thechumpsbeendumped.7797no ship is unsinkable. They made a choice not to build watertight compartments all the way to the top.
Also bad decision to try and turn if they’d hit the iceberg head on they wouldn’t have sunk.
@@Danfrank24
So you’re agreeing with me, it was a bad design.
I always figured the grooves were like drip rails on window sills to stop the bottom of the decking board collecting water.
Voted grooves down - UK.
No.
They are to increase friction when the surface has water on it.
The reduced surface area that your feet are standing on at the top of the groove increases the weight per square centimetre. That pushes the water into the groove and increases friction between you and the plank
@@Paul-yh8km Form the Timber Decking & Cladding Association..... "Contrary to some people’s belief, the grooves are not intended to provide improved grip underfoot"
@@unheard128
From the same page.
"Grooves are designed to channel water away from the deck..."
The intention may have not been to improve grip, but if the manufacturers understood a bit of physics, they would know the grooves would.
@@Paul-yh8km You are wrong, they are designed to remove water from the deck but they are talking about the underside. The grooves decrease friction a great deal, much like a dry ski slope. I explain in more detail in a post above.
@@stephenyoung1484
what post?
There is no age-old question here. The grooves are to dry the wood out and shrink the bottom first so that water runs off the top and to keep water from building up on the cross timber beams they're in contact with. Putting this kind of decking groves up is just begging to have to replace it 3x as often or more. On top of this you're also supposed to buy special out-of-square timber beams that also shed the water - nobody does that but its true. Ship-lap roofs occasionally also have a grooved face and it goes down as well, sometimes also with wooden shingles you'll find carpenter-roofers who know their shit who will try to always face rough or splintered or chipped surfaces down.
Exactly right. There's no actual debate. Just look at one that's 5y old and grooves up. It's rotten
Interesting video. Thanks for sharing. Before the video I would have said "grooves up" but now I think you've convinced me. At this moment I'd say "grooves down". I'm looking forward to the test result in 3 years.
I always thought the grooves were added to stop the boards from cupping?
Any thoughts on that, Andy?
I installed plain decking in the feont of my house in Belfast away back in 1999
.and in the back i used deck boards because i had steps installed. You have that choice when buying decking. Plain decking or grooved. But we wouldn't buy grooved to put upsaide down. Ty hat would be extra cost for no reason. And its was about £1- £2 difference in length back then. So in the case of my back garden which was all coverwd and raised about £200.
Curious about your answer... I've been told mine's upside down SO many times... usually from Australians.
I wouldn't expect anything else from people from Down Under! 😅
I'm from Australia. Grooves go down to allow the contact surface between boards and joists to dry out. Decking boards that are smooth on both sides are also sold here and becoming the more widely available option - I guess because it's cheaper to produce?
As a non UK follower I now put any deck in grooves down. I built a deck with grooves up but after 5 years removed it and reinstalled it grooves down for all the reasons you detail in particular - slippery, detritus and discolouration - needed water blasting every 6 months. With the grooves down so much easier to maintain and no longer dangerous to walk on!
The groves increase the surface area of that side.
Fix with the grooves down and the smooth side up in the sun helps keep the decking flat and not cup.
The same applies to the recess in the backs of architraves and skirtings. Been doing it since Adam was a boy.
It's about friction.
Think of Formula One tyres and the difference between dry and wet racing conditions.
Yes, I hear the groves can reduces the chance of board bending and deformation, especially in Australia’s dry environment, 100% groves side down for me.
Grooves and saw tracks are common on the back side of skirting boards,it is supposed to make the wood more stable and less prone to cupping, groves downwards would help with this problem also
No matter what, your patio looks wonderful ❤
I spent a while considering the same went grooves down for a couple of reasons. 1) I figured grooves down will give a better surface in the dry nice also easier to clean and manage. 2) I went this way taking inspiration from the window sills in that water can traverse the complete bottom of the wood it must drop off after first groove.
My bet is reversible is simply their way of saying we don't care, suit yourselves and give us your money. I'm for grooves down, I'm an interior flooring installer for 35 years so not my trade but I see a lot of houses and many after some time has past since construction with them up they are often in aweful condition and usually far more slippery and if they have been stained (coloured not dirty) its patchy as the staining tends to wear off the top of the grooves leaving raw and further coats end up uneven. If the tops smooth and you ever need to repair it you have no profile to match and if you wanted to sand or plane it to remove a board cupping or twisting where you maybe stub your toe on or w/e you can without losing the grooves and ruining the look of the whole deck.
Brilliant question, this is why the tint’ernet is great 😊
Only just picked this up 😞 - Mine's installed grooves down. We've had hundreds of years with wooden sailing ships and none of them required grooves to prevent slipping, it just needed to be kept clean with a bit of sand every now and then. So that's what we do, clean it that is not the sand 🙂.
Grooves down looks much better. From personal experience, grooves up on a deck that was not well maintained was a pain to clean and re-protect. I used a jet wash and for it to be effective, the pressure was too high that resulted in a fibrous finish (but clean). I then had to sand but hat is where the problem lies ... the grooves. I certainly wasn't going to sand in the grooves. Then the application of the protection - another pain. Had I seen this video before the decking was laid, it would have been smooth side up. Thanks for the video, I now know what to do in future.
I've been 'grooves down' for a few years now, having experienced how slippery these boards get with the grooves facing upwards, having to then clean and maintain them - those grooves only make it a greater challenge and for no benefit, in my opinion.
In the Karate Kid, Miyagi's decking had no grooves and he never lost his footing. Daniel would've walked away, had he been required to scrub grooved decking! 😅
Here in the UK, we had a moderately 'damp' climate. As a carpenter, I'd only want grooves on the underside of timber so that water can drip away (weatherbars and sills, for example).
As a nation, we're notoriously bad (I think) at maintaining our external woodwork.
My next question would be, where does the trend for timber decking eminate from? A country or continent with a drier climate?
Er.. I guess it emanates from .....a desire to do something quick, easy and relatively cheap ..... !!!
Lightweight materials... copes with uneven ground, slopes etc etc ....!
Initially thought grooves up, but you convinced me of grooves down 👍
Well presented Andy. Take care.
Thanks Andy, I agree it's mostly personal preference, and yes I think the large growth in the use of decking following popular TV shows is partly the reason people have strong preference in the UK ! I've done both for different projects, in fact I currently have two garden tables I made with decking tops and one is groove up and the other groove down, the groove up is treated with a spirit based fence treatment that I regularly re-apply and the smooth is treated with one of those non-slip deck paints so I'll be interested to see how they compare over the years ! Top take-away here is "If you like ribbed, then choose ribbed !"
@@andyc972 'treatments' can reduce the life of your wood as they can trap moisture underneath them. So it isn't a fair test either way.
Decking is cheaper that is why people do it probably 60% cheaper than a patio, you need foundation's for retaining walls, sub base, drainage and steps for a raised patio it will also last forever. Unfortunately decking only has a ten year life span before it starts to deteriorate , surveyor's don't mind having the paving the same height as the internal floor so long as you have a water break between the slabs and the door frame. normally install a blade drain to the soakaway. if your extension has a suitable DPM wrapped to the DPC you are all good.
Not sure why your surveyor doesn't like patios at the same height as the floor level in my 40 years of running a construction company it has never been a problem, Decking is the cheap option !
Oh Andy. You said they built the Titanic there and you trust their judgement. Look how that turned out 😂😂
Titantic was grand when it left Belfast:-)
@@johnm3413 It sure was John. Some rumours about smouldering coal in one of the bunkers but the Pratt of a captain couldn't steer 🧐😁
I mean it's not the manufacturers fault. Can't blame Airbus if you crash their plane into a mountain and it breaks
The last time I bought decking, both sides were grooved! One had 3 big grooves, the other side was like 15 smaller grooves.
Interesting video, I had always 'assumed' it was grooves up, but I don't know why 😂. I guess my question would be, what purpose do the grooves serve ? Are they decorative ? Grip ? Drainage ?
They increase friction when the planks have water on them.
The weight of your body is only on the top of the grooves, that's higher kg/cm which will help to force the water into the grooves and increase friction.
Think if car tyres.
Treadless tyres are really bad in rain but brilliant in dry conditions.
In theory they counteract the tendency to bow.
I see you are wearing your cap with the peak facing forward. We need a poll: peak forwards or peak backwards! Sorry, joking aside, a very interesting video. I'd always assumed grooves upwards but had not considered the alternative.
Grooves facing down...to provide for air circulation according to most manufacturers specifications
Canada Checking In: I've never even SEEN grooves on a deck board. Smooth top and bottom is the rule here, unless you're looking at a plastic/composite board.
Same in Sweden, I've never seen decking boards with grooves before. Recently composite decking boards have turned up with grooves in them.
I'm thinking that grooves up or down would be a pain with a couple of layers of packed snow on top or ice expansion cracking from below.
Top tip. You should look at Percy Hudson's in North Shields for your timber. Used them for years. Its an old family business, and their quality tends be be a cut above other suppliers.
Never thought about it before, just assumed the grooves went up. My parents have a grooves up which get very slippery when wet.
I think the argument is that the grooves act as a gripping surface and the problem with a flat surface is similar to a sort of aquaplaning in a car. But thinking on this more, most people wear shoes that have their own grip so the only thing grooves up is giving you is 50% less wood for your shoes to grip on to stop you sliding.
So I think if the decking is to be outside and used when it is cold and wet you are probably better with grooves down, but if it is only likely to be used when warm and dry, or is under cover, then it is just down to personal preference.
Great video!
In my experience, decking often attracts vermin though. Might be a good video-how to avoid that happening!
Use the groove sides up on the edges for decorative only. Or groove up every few boards for same.
You will find it’s very slippery if smooth side up, especially if you leave leafs . In general the both sides groves planks are decorative side up and a smaller grove to allow the board to flex to screw down.
Always gone with grooves up for dry climate/under cover (stops water collection and rot) and groves down for wet areas giving less contact with framing and better air flow at frame contact.
Quite right. I got sick of cleaning the green slime off. And slipping on it, as it's grooves up. Wish it was done the other way. There's no extra grip in fact it's slipper as it stays wet all day, water in the grooves. And it's harder to clean. I put anti slip stuff on in the end, which was great, but it was harder to do with all the grooves.
Why not install the boards alternately groove up and groove down?
I go with grooves down as i feel the damp under the deck causes expansion on the underside and curves the board, the grooves help to control the expansion when the top is in the warm air.
When I did my decking for a kids tree house I used the Wickes and B&Q youtube guides which showed decking being laid groove up, I only found out about the difference of opinion afterwards.
Also I found with grooves up no issue of worrying about protruding screws as I screwed into the grooves
But I do understand rather like the "extension" effect of the room to the deck
Used to be able to get deck boards with wide grooves on one side,and finer grooves on the other side.
Grooves up never clean. Grooves down better water run of and really nice to walk on.
What’s the use of the groove if it’s meant to be on the bottom?
So, I spent over a decade working for an Australian Timber Research body, whose main purpose was to develop building codes for the use of both domestic and imported timber. When it came to decking and in particular grooved timber products the recommendation was to have grooves down so that moisture and debris would not collect in the grooves causing decay and failure of the decking material. Additionally, grooved timber always bypassed import duties of raw material as it was considered a milled value added product therefore economically equivalent to domestic products. That’s the Australian situation it’s got nothing to do with slippery deck but importing and market penetration.
I do wonder if the grooves are intended to assist with differential thermal effects? When exposed to sunlight during hot summer weather I anticipate that the upper surface of the boards will get much hotter than the underside. This differential thermal range across the depth of the boards may result in them arching upwards across their width, possibly causing splitting or slight lifting of the fixings. The grooves may therefore be intended to be installed upwards to enable better ventilation and distribution of the heat and thereby equalise the thermal temperature range across the depth of the boards?
I just laid composite decking for the first time which i got at Eurocell and i wish i had gone composite long ago. My back garden is very shady in the winter and my wooden decking was so green and needed a fresh staining each year. It cost a lot more but I think its well worth it. i laid mine grove down too as the groves up take a lot more cleaning.
The grooves are designed to reduce the contact patch between both faces of timber. The only contact with the upper side of the decking just contacts feet and furniture. The grooves act like water dispersal tread on a tyre, but rather than being forced out by pressure with a
tyre, it’s the grooves and accompanying capillary action that allow the water contact to be vastly reduced and helped to escape.
The original boards only had one side grooved, Other boards with both sides grooved and words like "reversable" came about later after so many people fitted them INCORRECTLY and made it fashionable. The grooves are meant to go on the underside as they act much similar to a drip on a window sill (the groove on the underside). The water can only travel over the edge of the board up to the first groove then drops off. The water can only travel over the long edges of the board as the ends are mostly sealed with the edge boards. This results in the board drying out ofter rain much faster as water cannot travel to the centre of the boards, preventing rot, obviously, Fitting them groove up makes them slippery even with a small about of moisture (acting much like a dry ski slope) and helps a great deal in hold water for a lot longer on the surface and the underside, resulting in a short life span. Hope this helps.
I've yet to get past 4:51 but will finish it. The quick comment is why you ran the boards in line with the floorboard was probably because you wanted a smooth transition from inside to outside and if you laid the boards the other way round you would have had a step of varying height across the patio doors due to the fall from one end to the other to facilitate drainage.
Another great video from GHM ❤
Surely it takes a non-zero amount of effort for manufacturers to create those grooves. If they don't serve a purpose and it's to go flat side up... why do they bother?
I’ve slipped on decking grooves up in the winter because after a rain or hail storm it’s frozen and become like an ice rink.
I was told that the original reason for grooves in timber planks was for 'stress relief'. It stops the plank bowing. As this may be the case, it might make sense to lay the boards groove down because it was never designed to be aesthetic. Maybe with your experiment you could try a plank (same board) with no groove and grooved to see if there is any bowing.
Flat side up can see the real wood grain look after oiling. sometime can find the good quality profile with fine mall grooves on the surface and big groove on the under side, this give people a clear anwer.
I looked into this about twenty years ago when we installed our siberian larch deck, taking most of my advice from what was then called the Timber Decking Association (worth buying their guide for anyone about to design and build one- great advice on species/span tables etc.) Grooves are essentially a British development; at that time they were virtually unheard of in North America (where decks were ‘invented’ ) Grooves are commonly used where antislip is an issue, but predominately on materials which don’t support algae growth. I’d also suspect that grooves on one side may lead to timber bowing / cupping, but that’s a whole new discussion….
The grooves on top will trap more water then if they were on the underside plus they also get very dirty and grubby. I did hear that the grooves act like a drip edge so water running down the edges of the board and underneath will drop the moment they hit a groove
Andy,
A cracking review.
My main concern with groove up is that as you say it traps cr@p which promotes algae and mainly tracks water to the ends of the run or joints which seen to be a point of rot out as they see way more water.
And if the deck is layed up n down (not a consistent drop) along the lengths it traps the water
I'm a grooves down guy
You didn't mention manufacturers guidance much Andy - since you showed a piece of Arbordeck timber as your example I checked their 2024 installation guide out of curiosity - and it shows the boards oriented with the grooves down!
I disagree with the comments about fall. I live in Wales, and many of my stone paths slope visibly. They all get slippery even a month after a pressure wash. Of course the slope makes it more ski slope than ice rink! Must wear good soled shoes and boots and use the hand rail. Yes it was pressure washed in September (end of October now), do the old fashioned treatments work longer eg Algon and Jeyes fluid?
My decking was laid grooves up and needs replacing due to rot. Didn't stop it being slippery, hard to brush out the detritus, smooth side up looks favourite for the new one.
Looking forward to your next decking discourse, thank you.
Personally I can't be doing with decking . It's slippy when wet and frosty and a potential haven for Roland and his mates. But if I was going to, I would use composite. But it's all personal preference 😊
As long as you got a good air flow underneath💨 should last a long time 😊
AUSTRALIA QUEENSLAND. I used Mixed Queensland Hardwood, smooth on both sides , but it is all mostly protected from sun and rain. Two decks, ,8m x 2m and 8m x 4m, patio is paved at 8m x 4m
I've got smooth side up and 2 years later defo made the right decision. I was told it might get slippy. I haven't once come close to slipping. Visually it looks much better. I've oiled it and it's way easier to clean smooth side up. Also, grooves down mean air gets to the joists. So an absolute no brainer for me.
You mentioned not building a patio because of potential issues with surveyors. This has spooked me as I have MS and plan to lay a patio about 10mm lower than DPM (with channel drains where it meets the wall) so that i can access my garden with my wheelchair when my legs don't work.
I know that building regs are changing with accessibility in mind. Will that change what surveyors pick up on?
My property is a bungalow with concrete slab foundations and no vent bricks. Does that change the equation?
A video on accessibility might be interesting tbh. It's always a good thing to consider with projects.
I'm in a wheelchair and my dad is a chartered surveyor. Accessibility doesn't give a pass on building regulations, quite the opposite. You would potentially need drainage such as an aerated gutter if you were not using a floating deck as you stated. A concrete slab floor does make some difference. Things like the angle of your garden make a difference, too. The drainage would have to be adequate, if the garden is higher than your foundation you may have more difficulties and your water run off can't affect your neighbours or increase the run off onto a road. I have decking to pavers with a french drain under the decking with a upwards sloping garden.
You shouldn't get spooked, you just don't want your house flooding.
@mandowarrior123 I live on a bit of a hill with the ground sloping away from the house on all sides. My garden slopes by about 30cm over about 7m so I'm not concerned about water coming into the property as I can slope the patio away by more than enough and the runoff will mostly go into the gravel in my garden apart from the path that goes to my back gate.
In my research I've seen lots of people saying to leave a gravel gap of 100mm between the paving stones and the wall. The channel drain I was looking at was 115mm wide so I think that is adequate and easier for me to maintain and then I found a page on the NHBC website titled "accessible thresholds" where they say a 150mm splash barrier should be fitted "using an impervious wall finish or cladding" and so I think if I put in some kind of flashing to prevent the 150mm of bricks above the patio from getting wet from splashes then it might be okay as long as it's not something porous that would bridge the dpm.
I wish there was an easy way to contact building control to ask for advice. The only way I can contact them would be to submit a plan and the most relevant category they have for my local council is "alterations upto £5000) which has a charge of £283!
Edit:
The NHBC thing was about balconies which makes more sense with the flashing/cladding thing so it isn't applicable. After thinking about it some more I think I could leave a gap of around 150-200mm between the paving and the wall with the edge of the patio supported by a couple of courses of brick and have a french drain between the patio and wall with the finish height of the pebbles are below 150mm from the DPC. I could then make some kind of bridging material out of wood or composite decking to cover the gap but allow for drainage. It's basically a scaled up channel drain but deep enough to avoid any issues with building regs.
I've been to two completely different properties, one with decking as a raised patio area and the other with decking as the flooring of a gazebo, someway from the house. They looked great but rats had taken up residence beneath and became a big problem. Just a thought! ❤ XXX
Dect
My garden has 2 bits of decking with it laid both ways, both are as slippery as an ice-rink for most of the year.
Any tips on how to make decking less slippery?
A bloody good question.
Grooves down you might think it makes it non slip it doesn't fitted upwards so it makes sense to put the groove down. The water sits in the groove and dirt as well wearing the wood down over time.
Groves down for air movement and timber stability. It is also less slippy as no water, algae, moss etc builds up in the grooves
you will get much greater water penetration with grooves up - so if you want it to last - grooves down !
Just be careful when its frosty which go’s for all external wood flooring scaffolding etc anti slip coating might be a good ideal if you use it a lot in winter.
Good video Andy and I watched it all and gave it a like. But, I don't have a deck, can't see me ever having a deck so, I don't really care!😂🤣 That said, I answered grooves down on your poll. Cheers.
Hi Andy, It's just down to personal choice, I did vote grooves up, I just picked a side I chose that, no reason. Summer last year I gave my brother a hand laying his decking and he chose groove side up. It could have been worse it could be, A) Groove side up.or B) flat side down Your choice🤣🤣As always a great video take care
Use an extension to kill the popups.
The whole groove thing depends on the kind of wood, whether it was treated, the size of the grooves and the way the wood was cut. Ordinary wood that is quarter sawn doesn't matter but you are unlikely to get that for decking.The harder the wood, the less likely it will cup.
''Cutting a piece of flat sawn oak will yield a plank that not only shows a significant flame - or cathedral - grain pattern on its face but also one more prone to cupping. Wood tends to cup in the direction opposite the bend of the growth rings. Due to the angle at which its cut, flat sawn oak will almost certainly begin to warp over time as the growth rings are set at such a low angle to the face of the board''
If you notice flooring for indoors, they will almost always specify which face goes up.
I shipped some out to Spain as lumber is expensive there. Fitted it rib side down.
Here in Norway, most of the decking sold, by a large margin, is smooth on both sides. You can get with ridges on one side, but it's more expensive.
My sister had hers done grooves down. Because it was in a quite shaded area and the UK weather it always has thin slick algal layer on it which was absolutely lethal, Grooves down unless you're dry and unshaded or want a maintenance headache.
Made me think, on ships where it came from it is always smooth side up to allow the water to run away.
I prefer grooves down and have it installed like this for the look but after a few years it's now incredibly slippy in winter, like dangerously.
It was my understanding the grooves are to stop the boards cupping? But you omitted this in the video, and no-one seems to have mentioned it in the comments.
It would be interesting to now do another poll after the video. I would have voted up before (uk based), but now I would vote on “personal choice”, but I would personally prefer it down.
I have hard wood decking and both sides are smooth. Such is life.
Andy, one question about dpc and deck height. I was under the impression that the dpc was 150mm higher than the ground to prevent it being breeched by splashback when it rains. Would you not get a breech of the dpc installing decking so high like with yours? (especially if there is minimal overhang)
If the boards are made with the grooves face down, what is their purpose?
Never seen grooved decking in my life, but if I was presented with it I would definitely assume it was made to keep the joists from rotting.
I live in the UK. I had always assumed that the grooves were there to help with grip and reduce slipperiness. It had never occurred to me that having the smooth up would be a good idea. I assumed that there would be no point in going to the extra expense and time of having grooves, and then having them facing down where they would no be seen and serve no purpose.
The idea that they would help improve ventilation on the underside seems unlikely; the grooves are far to narrow for that. Maybe they would help with encouraging water dripping off though.
My recent experience with decking with grooves up makes me feel that grooves up is a bad idea. (This decking was not installed by me and is of unknown age.) My experience is that the grooves retain water and general gunk and make difficult and tedious to keep clean. In certain types of weather it is very or extremely slippery.
In one area it has rotted so much that it now has holes.
I do not have any experience with smooth decking, but I would guess that it would be easier to keep clean.
My experience with flagstones is that they are *not* slippery, even if covered in wet moss. I was surprised how non-slippery they were, even when wearing footwear with pretty smooth soles. These were quite roughly textured, horizontal flagstones though; on a slope I would not be quite so sure though.
If you have moss-covered flagstones that you like, I suggest you do not assume they will be slippery when wet: check this out before cleaning it off.
If I ever am having installed a "decking"/patio area for myself I would never use wood, I would have rough-textured flagstones.