Why Do You Have Condensation in Your New Roof?
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- Опубліковано 15 вер 2024
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Hi Roger,
Heard you on radio 2 earlier today, I’m a plumber and I completely agreed with everything you had to say about heat pumps, the other guy David is clearly just a salesman for his product and that line of product.
He was obviously just there for an argument, made me laugh when he replied with “that’s the biggest load of rubbish I’ve ever heard in my entire life”, I thought surely that can’t actually be the biggest load of rubbish he’s ever heard in his entire life, you made some very clear points and were stating facts about home insulation and heat pumps. Heat pumps are good in the right property, but how can a row of terraced houses or small block of flats possibly install this system practically, also completely unaffordable for most of the country, even with a £5K grant.
I only caught the tail end of it earlier but I totally agree. Often when people have a point to make that is sketchy at best, the adoption of a tone that undermines / belittles the the other ( Roger in this case), makes them seem more plausible.
People who know, know. Keep it up Roge 👍🏼👍🏼👍🏼👍🏼
Hi Sam
He is certainly a salesman and wasn't willing to admit that not every property is suitable. I think it smacks of desperation and he will bully people into buying. The best bit is that he is going to show us a 2 day installation and let us film it. What is the betting it never happens.
Anthony
He was an attack dog, trying to discredit me from the off. The manufacturers of heat pumps say they should not be placed near bedroom windows where the noise can cause a problem, or near neighbours but he is saying they are whisper quiet. I love the claim that the pipework doesn't need changing. If you put big radiators onto small pipework it achieves nothing.
@@SkillBuilder ha ha, can’t wait for the 2 day installation video, it takes a couple of hours just to commission one properly, they’ll probably just throw 10 plumbers on the job, but like you say, it’ll never happen.
Also loved how he was making out how clean heat pumps are and how gas boilers are killing everyone off daily.
Don’t think he realises that most of the electricity produced in the UK comes from burning fossil fuels and heat pumps run on electric.
Bit gutted I missed this. There's so much debate on the topic of heat pumps and having watched Rogers last few videos on them I'm in total agreement with him. I've had experience of them installed in unsuitable social housing properties where they were taken out and gas condensing boiler installed (again).
The best way to stop moisture/condensation, is to cut out the source.
All people must stop breathing.
Job done and Klaus and cronies happy.
These clips are way better then what's on TV!
Heard you on radio 2 today Roger...you are correct in your analysis of the heat pump debate the opposing contributor today was talking nonsense mostly...
Hi Roger, I'm a building inspector, in fact I'm the Head of building control and was a joiner/builder for 35yrs, and I'm not confused at all and agree with what you say but I'd like to add another couple of points. Firstly if you replace more than 50%of any thermal element of a building i.e. Floors, walls and roofs, you should submit a building regs application. I'd say 75%+ of all our unauthorised works are re-roofs. This is because roofers also don't like doing insulation which would be part of the requirement, to bring up to current u-values.the rowers don't usually care and if we don't see them the owners may have trouble selling with no cert. Secondly, you're right that they should check with the manufacturer and also the BBA certificate as this will give specific fitting instructions. Usually the amount of sag between rafters is specified. I have rarely seen a membrane fitted to spec because as you say, they're usually on a price and also they'll pull it as tight as a drum as it looks shite when it's sagged. Finally an opinion of my own. I'm concerned about the longevity of the breathability of these membranes. As you know, when you rip a roof off more than 20 years old there's all sorts of detritis, dust, rubble, insects etc etc. I think in time we will start to see issues arise from this. Although in some cases I can't insist, I will always advise cross ventilation......again as long as its not blocked by stuffing insulation right down in to the eaves. App it takes really its good workmanship and attention to detail.
It's actually 25%.
Through ventilation of loft spaces is the way forward no matter what 'breather membrane' is fitted. We always vent at eaves AND ridge.
All true.
Well I must say your the first person in a long time to mention the sag in roof membrane installation. It all has a bearing on build up of moisture.
Completely right about waste being caught in between roofing membrane and battens no different that mortar in a cavity it will transfer moisture to the warmest areas thus creating problems in the near future.
We had a video on the sag
I am just a brickie but your needed in every college in the country right now, most lectures don't how a clue go kick them into shape. When I say only a brickie I mean the most important trade on site but I need to know this stuff! Thank you lol
Brickies are the backbone of the industry
You are not just a brickie 👍🏻💪🏻
Without me the lights don’t shine. Yep you’re just a clay stacker. 😂😂😂
When You the “ the country” I presume you mean England. Totally different building regulations here in Scotland. Interesting watching how different things are done in England though.
Brickies are 👍. One of my best pals is a brickie turned stone mason and listen to all his stories on the building industry. 👷♂️
For a plumber Rodger you got a great understanding of building fabric design 👍 bloody good explanation for the let man , many ain't got a clue , I take me hat of too you sir 👍💓
After 48 years of trial and Error with the Problem of Black Mould in the Bathroom Ceiling and Bedroom Ceiling along with Heavy Droplets of Water on the Newly Fitted Roof Membrane some 15yrs ago
A SOLUTION for me CAME IN THE LAST 2 YEARS.
I Fitted a Dehumidifier 10litre from Argos in the Attic with 100mmx40mm Channel PVC Ducting going to an Extractor Fan with Humidistat Auto Settings Above 55%. Humidity, with the Condensation or Moisture then going from Attic to original overflow pipe outside , that made all the difference.
HEALTH Benefits was my Main Achievement.
Tom.
I am a chartered architect, and I am always looking at your videos. Very useful information for home owners. Thank you.
I also like to see the construction process from the builders point of view. It helps in the design process.
An old draughty roof has always been the best ... We seal up roofs and cause problems exactly the same as double glazing and hermetically sealed interiors
Here here.
May I add draughty sash windows as well.
Could you talk about loft boarding and how it would effect the ventillation and moisture migration one day please Roger?
Roger has explained how moisture passes through the roof and some pitfalls. If you have the roof boarded or not, just follow the steps in the video
It's raising damp lol!
Couple of vital of info missing on post (although as a roofer myself ,spot on about cheap membrane) Firstly the lower the pitch of the roof , the more condensation it gets. Secondly roof tile vents only work by cutting holes in the felt directly where vents are strategically fitted.
Thirdly there are spacers available really cheaply that will separate the felt from the inside attic space that will solve the problem alongside which is already rightly explained in this vid . Great post tho all round
I've noticed the condensation in my loft - thanks for this, Roger - I now know what I need to do. Another excellent, informative Skill Builder video. Thank you 👍👍👍
Hey what did you do in end to solve the problem?
Good to hear you on the radio today
Heard you on radio 2 today Roger!
The law of thermodynamics says vapor turns to fluid where heat meets cold. If you have a vapor barrier like paint in the room the drywall diffuses the exchange to attic by slowing the temperature change rate . Insulation also creates a larger area of slower heat exchange. Any barrier in the insulation like paper or plastic will create another vapor to fluid formation exchange point . By creating vents to attic you allow the temperature range difference between outside air and the attic space to stay relatively close . The roofing material creates the next vapor barrier , which side is warmer is where the vapor will turn to fluid and sweat
Your bit early on about the suction from wind is slightly wrong. Aircraft wing - yes ... but the pressure reduction begins as soon as the air is pushed up the windward side, the pressure is lowest at the top and then increases again as it goes down the leeward (downwind) side. So the maximum suction is around the ridge on both sides, not just the downwind. Of course, if a tile lifts on the windward side it may be caught by the wind and ripped off - less likely on the lee side.
(The why is actually fairly simple: In order for all that air to get over the roof (or wing) it has to speed up - because there is less space for it. The only way to get air (or water if you're a plumber) to speed up is to apply a pressure difference, so the pressure at the ridge must be lower than at the windward eaves. Once past the ridge the air has more space and needs to slow down, so the reverse is true - the pressure at the leeward eaves is higher than the ridge.)
Good video👍 very educational. You did well on radio2 today. I'm still not convinced by them new heater things. Can't believe vine just called you a plumber, the cheek of the disc jockey.
I was sorry that they didn't mention Skill Builder, I wanted the boost for the channel
Vine is ignorant calling Roger a plumber. That is merely one string to the bow of Mr Bisby! Roger is bang on with his opinion of heat pumps in my opinion.
The guy who does my roof tiling came up with a good idea, he put short sections of 15mm pipe between each felt drift to provide ventilation, you can buy purpose made felt trays to do the job but the pipe works
Yes, I did that about 10 years ago - no condensation at all. I used 32 mm waste pipe which might give more air flow than 15 mm. Cheap fix that actually works!
@@robdavies68my mate said it cured his condensation too. I recently used it on a refurb listed building I’m doing, could use eve vents at the bottom but no vent through so put it in each rafter bay at the top of the vaulted ceiling and hopefully it’ll work well
I have this in my house but it's little polystyrene blocks. Always wondered what it was for and considered taking them out
Hi Roger. Lovely to see how knowledgeable you are about this. I think this comes from being involved in different areas of the industry. So many people stay in their lane and say "not my job" whereas guys who take on the whole design and build process see the big picture.
This is a tricky subject. Ventilation can also create more mold; colder air does not carry moisture as well as warm air. I am talking about Northern Scandinavia.
Very interesting and informative - good to get down to the basics of roof void ventilation. As you point out, not all so called vapour permeable sarking felts are the same. One way or another moisture must be able to escape from buildings or else it will remain trapped and is likely to cause problems!
Hi Roger, I don't have a new roof but wish to create an insulated store room in the loft space, I'm hoping you may do a video on this some day.
Well done on Radio 2 today, it was great to hear you talking with Jeremy and explaining the truths about heat pumps, your recent video on the subject was great.
David seems an arrogant salesman sadly he will sell to unsuspecting victims.
Gosh, this is a very good explanation. Better than most.
After moisture running down the roof liner I've run one of these for a year with no damp issues. I use it to just blow air around the roof space. It costs about £8 a year to a year.
I'm talking about a Vent Axia Lo-Carbon PoziDry Pro PIV Ventilation Unit Model:476310 (No Heater)
Fantastic video, tackling this issue right now.
I've just put in 300mm of rockwool, but before i did, i cleared all the old crap out the loft, old 20mm insulation and have stapled eaves ventilation panel to the bottom of the rafters to let air in, i'm DIY, and it amazes me that this isnt known!
🎶 Insane in the membrane, I’m insane got no brain 🤯
Thank you for all the wonderful Content..on Skill Builder 👷♂️ Channel.... Nothing like learning from the best 👌 old and wise in the civil engineering industry ...experience approach to all types of work with the best skills for all viewers out there to get a load of... thank you... 😊
Well it's the holiday seasons again why don't you guys book a ticket down to the Fiji 🇫🇯 Islands a much deserved Holiday.... like they say the work will never finish......Great craftmanship great skills 👌 ..from Fiji 🇫🇯 Cheers 🍻 Brother
Great video thanks. What would you consider to be the average moisture content we should expect in a loft for a new house during the winter? I have recorded humidity levels in the high 90%s. A neighbour also took measurements in his loft with similar readings (max. 99%). I appreciate that new houses take time to dry out and we plan to check again new winter. We have lived in the property for the past eight months.The site manager has been very helpful and has inspected the loft to ensure the insulation is not obstructing the ventilation in the eaves. Having previously lived in two new-build houses in Guernsey constructed with 'cold roofs', both had consistently dry lofts and we were able to store boxes and clothes without any signs of damp.
I enjoy your interview today on R2.
Thanks, it was hard to get very much information across in the cat fight but hopefully people will understand that the salesmen are going to promise everything and deliver dissapointmet for a lot of people.
You. could fix extractor fans in gables controlled by humidistat. Very few houses will have vapour barrier at ceiling level or vapour permeable felt to roof. The problem is at its worst when heating is on in Winter when you have heat on and it is near to freezing outside. This is best time to check. Otherwise the dew point is not present within the structure so does not appear.
Great video & an important one. And your presentation is great, structured & logical, as always
I have seen your block & beam floors video of 35A, several times, both the laying of it & the screeding. My questions are these
1. The prep work of the beam & block work I.e. slurry etc is missing in the video mentioned above. There is also underfloor heating. Could you provide a video on prep work before screeding on beam & block floors, even if it is theoretical without any onsite videos?
2. If we were to use beam & block flat roof, how would we go about waterproofing it in a
A. Cold climate
B. Hot climate
C. Cold & wet/damp climate
D. Hot & wet/damp climate
Thanks in advance. Keep up the good work!
Ah! Ok
We did brush cement grout into the gaps and then laid polythene before the insulation went down. I don't know why that wasn't in there. I will talk about block and beam outdoors, it needs a good bit of waterproofing
@@SkillBuilder thanks & look forward to a video on beam & block flat roof start to finish
1. Not so much the laying of beam & blocks & the different varieties of block I.e. light concrete, styrofoam, polypropylene etc, but more on
2. Waterproofing a cement block beam roof, including insulation for hot weather, as concrete absorbs heat & releases it after evening
3. Make it ready & fit to walk on, have a terrace garden etc in rainy, hot weather
Thanks for the video Roger - and the others you put up. Seems to be a metophor for the times, but after building houses for 200+ years we tried to improve the concept and made it worse! (Don't ask me how I know.)
Excellent information, clearly presented. Thank you.
Goretex jacket vs plastic mac.
The stupid thing is if you're going to make a sealed house you should like is common in passive housing and new NA builds, seal your roof so it's classed as conditioned space too, that would avoid many issues but unfortunately building standards are lagging behind. Something that is going to cause no end of issues in the next 10-15 years with the advent of new electric low temperature heating systems.
I wonder could the roofer and the builder have a quick conversation about the ceiling, and any barriers etc that might influence the membrane choice. Seems madness to have clients spot this?
A Cross battened roof with continuous over fascia vents is the way to go, allows for full rafter insulation and is the best method for roof ventilation
You are dead right, not many people understand cross battening
My new build had moisture problems. 1: the insulation was blocking the vents in the eve's, 2: the loft hatch was drafty.. 3: the bathroom extractor wasn't even connected to the pipe!
Nightmare - 2 years it grew mould on the membrane, OSB and rafters.
Fixed the 3 problems i don't have a drop of moisture up there.
Had all same problems in mine.
Sorted now.
Thank-you, this explains our soaking darling!
Good video, I’m a builder on cape cod and I’m wondering if you guys ever use architectural asphalt shingles like we do here?
Hi JN
We only use those on garden buildings not on our houses because they are looked upon a low grade roof covering. We are looking for 100 years lifecycle.
BTW I took a vacation on Cape Cod some years ago, we ended up in Province Town, that is an interesting place.
@@SkillBuilder This is horses for courses of course. We think of corrugated roofs the same way, but in South East Asia they use it as it stands up to the weather well, better than slates and tiles, and in parts of Scandinavia you will often see corrugated roofs using Onduline or similar. I am not a builder, etc, a bit of a DIYer, but research everything that I do or will get somebody else to do.
BTW I have been through a mouldy roof within a few months of a new build in the mid 1970's when the builder omitted installing vents adn once they had it cleared up within a few weeks. Current house only has slates and no felt or breathable liner, built in 1949. Roof space is really cold in winter but hot in the summer, but no mould or dripping water.
I'm a roofer and will always pay the extra for Roofshield membrane!
Good to know
Make sure your vents in your rooms are lined. The air can be pulled up from there big time
Exactly describes what's going on in my loft thank you
i think the fundamental problem here is that it’s one of those situations where its easy to get right, but just as easy to get wrong- well for a lot of people. As a contractor, i feel i always have a hard sale trying to convince the customer on paying a little more upfront- for quality, reliability and a robust system.
Hi Roger, great video as always. I’ve just started getting a small damp patch through my lounge ceiling. Looking in the loft (today) there are a lot of water droplets on my vapour barrier, all over the old section which wasn’t celotexed. It’s a new roof (tiles & vapour barrier) with 200mm rock wool which has started to get saturated! Watching the video, I’ll get some ventilation circulating. My question is, should my builder have known this would happen, and advised us and secondly would the chimney breast have any effect in winter making it worse. Thanks
Thanks good sound advice and practical approach.
Hey Roger. i love the videos. as i will be starting a new build hopefully early in the new year these videos give me great ideas. if you ever get a chance i would love to hear your opinions on roofing, as in slates, PVC sheets or metal cladding. I was thinking of maybe going with PVC. I would love your opinion on that subject. Keep up the great work all of you.
I have seen a few old houses with shower extractor fans venting into the loft, sometimes it is done so that the people who built the en suite or whatever can do it without drilling through thick walls, or seeking listed building consent, or maybe some other reason
I'm currently putting a bigger dormer in my 1970s "chalet bungalow". As part of this, there's a 2-tile wide section of the original roof which will need to have the felt replaced (because it was under the original dormer edge, and has torn during removal of the dormer). It's currently a fairly heavy bitumen-like sheet, to which the fibreglass insulation has attached itself (I think over the years). The roof has never had moisture problems (there are no vapour barriers, and I think the roof is well ventilated as it's always dry), so I want to replace it with something that will work for me (and preferably do the job myself, as I'm doing most of the other work myself). Should I just go for a good three-layer breather membrane? I only need about 5m x 1m of it...
yes change it while you can
Another brilliant video. thank you very much.
My Partner moved into a new build that was mouldy in the attic from day 1.
Builders said it went up mouldy (Bugs are on it eating the mould and come down from the attic through crevices).
She complained 25 times over 5 months and nothing was done. They have finally said that the attic passes NHBC recommendations so they are free of blame.
The attic faces NW, and is a valley attic. All the valley boards are mouldy and damp and were so from before she moved in. It gets worse and then better, then worse again. It's taken layers off the wood.
They say the attic is drying out, and now she is adding to the moisture problem (we have been super careful to not do that).
I cant believe this is how it works. We get ruined and blamed for something that was already there.
My partner has just gone through a year of cancer treatment and should be nowhere near mould. Her moving into a new build with a mouldy bug infested attic is sickening. The building game disgusts me. Blaming homeowners for these moisture issues is too easy for them, The attic gets no sunlight at all on the valley sides but as long as the good old NHBC says it's fine, we suffer.
The NHBC are useless, they always take the builder's side in a dispute. I had a new-build which was a nightmare. The NHBC guarantee is not worth the paper that it is written on.
@@Cranstal Yeah i have wised up to the NHBC now. TBH the housing company, NHBC and the builders all seem one in the same.
There defiantly is some code to stick together against the public.
Its sickening. I cant even get a solicitor to help, They don't want anything to do with Housing disputes. No wonder the rich and powerful are able to walk all over the public.
Could you talk also about ventilation if you have converted your attic and find the same problem of roof sweating , very informative videos thankyou
I bought a new build with soffit and membraned rafters and boarded it out. After the first winter, I got in the loft to put in the xmas decs and it was dripping wet. Anything permeable was covered in mould.
New build is always prone to this kind of thing because the building is drying out. During that time a dehumidifier or ventilation is essential.
I recently put an extra 200mm of lagging in my loft. Obviously this blocked the eaves. To maintain the air flow I put 1m lengths of guttering into the eaves (at right angles to the eaves). This has kept the air flow into the loft with no problems seen. No fancy membrane on the roof just old fashioned sarking ( I think that’s what it is called).
That there is a top tip, thanks. I`ve also seen cardboard tacked in between the rafters to act as an air spacer
Yeah, I had the same situation and done the same thing. Fast forward 2 years and everything seems perfect - no build up of moisture anywhere.
Are felt lap vents good to help this? Do they work or can then damage if further or create another problem? Thanks for your help
I was wondering this as well.
Thank you Roger
nobody has once mentioned about the incorrect installation of breathable roof membrane. it doesnt matter if you buy a £10 roll or £100 roll. no roofer ever leaves the top wrap 50mm down from the ridge board! this process allows warm air to escape through the dry ridge system! if dry ridge system is not used then surface mounted tile/ slate vents are best
Thanks for video Roger. I have to replace my insulation and am not looking forward to that but at the same time I was thinking of installing one of those PIV units; do you have an views on them? Also my brothers house has no membrane at all (no felt or breather) the roofer told him that's ok but it feels strange to me... he doesn't seem to have any problems though.
good clarity Roger. I have seen previous videos. Looking to convert loft and insulate between rafters so will need 50mm? air gap between insulation and roof slates? also will need to retro fit vent holes in soffits as they are completely blocked.
"retro fit vent holes in soffits" or you can vent over the fascia or tile vent the eve space
Caught you on Jeremy Vine yesterday Roger top Job Fella, we had ground source heat pump fitted years ago.🙄
An old fashioned gable vent looks nice if your house has a front facing gable.
Thank you Roger : )
The man the myth the legend.
Hi Roger, I don't have a vapour barrier on my ceiling plasterboard. How about using liquid rubber sealant (like the ones used in bathroom showers) on the upper side of the board? Any cons?
Skills builder I have a problem with my builder please can you help me my friend?
This implies, to me, that the loft space would be better considered as a main house area and insulation a high grade such as celotex applied between the rafters, with soffit and ridge ventilation, Comments?
Brilliant 🤩 very insightful.
Roger heard you on radio 2 very measured response to heat pump guy who ranted after your input. Take him up on his offer and get a heat pump in. He couldn't answer the real issues. Perhaps an interview on skill builder and a site visit with him....
It would be a good video but I have a feeling he won't do it. Putting a heat pump in over 2 days if you have no hot water cylinder to begin with and changing rads is more than 2 days even with 3 people I would struggle. He has to run a power supply from the board build a hard standing etc.
We will see how that turns out
Quality video. Thanks
Worth checking that any vent hoses that go into the loft are properly connected, mine wasnt from the en suite when we moved in and the loft was soaking wet.
That happens a lot because the electrician puts the duct into the loft and the roofer is supposed to connect it to his terminal
Thanks.
Hi Roger !......Would an extractor fan automatically operated by a Humidistat, placed at high level in a roof space and ducted down to a grill in the soffit panel be a useful way of dealing with possible condensation problems ?
Heard you on Jeremy vine today. Are you sure you don't want to go on any training days for heat pumps?
I have done a few but not for a while. I hope that guy contacts me so we can go and film his two day installation.
What about the spray foam insulation they put on underside of roof? Cheers
If you have that it is very difficult to sell your home because most mortgage lenders don't like it
Thank You
Thanks!
Just came across this as we had a new roof in the summer and just been up in the loft and it is crazy wet up there not to sure where to go from here though I guess more vents?!?!
Hi skill builder. Just wondered if you can advise me. I have noticed that im getting some damp patches on my newly converted loft space. My understand from your video that it's most likely not enough venterlation. The vapour barrior used was the "£40" vapour barrior used. If the vapour was upgraded to the 3ply as suggested, do you think this would help/rectify the issue
We have a boarded loft with no insulation between the back of the ceilings and the underside of the loft floor. Can we just unroll insulation across the boarded floor to insulate the loft or will the cavity beneath the floor boards create a problem of any sort between the back of the ceiling and the underside of the loft flooring. The ceilings are all lathe and plaster, the house is 1930s build. The loft is just a loft and the floor boarding is just boshed in for convenience. Any guidance gratefully received. There also is no roof membrane under the tiles but that would be too much of a job as the roof is generally sound.
Leave you window trickle vents open in all windows and either have a big gap on the bottom of your internal doors or leave them open to let the air flow. Stop drying your clothes inside.
Hi Victorian terrace here. We had a new membrane (roof shield air and vapour open). Seem to be getting damp rafters in one area (around the chimney breast in the loft). Could droplets be forming on the rafter? Noticed over winter with heating cranked up
This explains my issue but what would explain the mould appearing on walls like under my stairs in the cupboard and in the corner of my bedroom both which are the same exterior wall. Also I have water mould in my loft on the OSB of the gable end it’s a brand new house
Hi Roger when you install the membrane behind the plasterboard flat on top I was worried about sweating in-between the plasterboard and plastic membrane, now you have mentioned it will fine ?
Thanks Rob.
Hello I need some advice. I have a new metal roof over my 1974 mobile home. The problem is condensation is building up above my bathroom, kitchen, and the small room in between is settling on the underside of the new metal roof and dripping down towards the soffit and in turn hitting the truss as well. I think the problem is we decided to vent all plumbing and exhaust fan through the soffit and outside, and maybe it exiting back into the attic plus that is the only spot on the whole roof where condensation is building up. Just to mention, we live in a very humid climate on Vancouver Island.
Our main heating is a wood stove.
Hi Dan
It is a difficult one because a humid climate is always going to create moisture but it also needs cold surfaces to condense on and cold air holds less moisture. I think it is worth hiring a dehumidifier and running it for a week without the extractor fans to see if that makes a difference.
I would think the wood stove is doing no harm and keeping the house dry.
What most of the old-timers who have experience and have seen my pictures, including a retired building inspector, said is to get that vapor out of the attic.
Corners were cut during the roofing process, and we decided to vent through the soffit, and it's backing into the attic and sticking to the cold metal. Every other area under the roof is bone dry except for the exhaust exit and plumbing vent exit, and there is
three vents within 15 feet of each. I am going to vent through the roof, and if I still see a bit of condensation, I will use double reflective insulation and attach that to the metal underside.
On top of that, there is zero ventilation in the attic anyway, nothing on top or at the gable at both ends of the house.
I am also going to make plans to buy a dehumidifier and have that run during the cold season.
I am about to tackle re doing my roof myself this summer can I get away with a non breathable membrane as il be fitting a dry ridge system and plenty of venting at the eaves and also have a long styled air brick fitting in the gable end.. cheers
Can membranes be retrofitted in some way without having to take the roof tiles off, is that advisable/beneficial? My 1930's house has no felt/membrane installed.
Does having your central heating boiler in the loft help or make worse the potential for condensation. Even the best boilers give off heat in operation as do of course all the heating pipes connected to it. Putting a boiler in the loft seems a common option now on refurbs as it frees up space in the rest of the house.
I think it helps to keep the loft drier but it is better to cut the heat losses
When boarding a ceiling with foiled back plasterboard, I notice that the foil overhangs 1 long and 1 short edge, is this to allow the next board to sit over this to form a seal?
If you have mould on the membrane would best course of action be treat the mould and fit vents in the roof?
Hi Rodger. I have a purpose built chalet with 2 dormas that finish In the loft space. I want to add insulation to my loft so I can store things in there in a nice dry area so looking to put insulation between the joists and in to the void above the flat roof to create a free flow of air from the front of the flat roof up to a ridge vent. Is there any info on ridge vents to take the air flow from the flat roof that joins in to the roof/loft? I’m struggling to get a roofer to do both reroof the flat roof and put in the ridge vents.
New houses have everything sealed, mastic around sockets, switches even down lights??
I’ve seen air tests done with vents, toilets, extractors all covered, just to get the correct reading. 🤦♂️
Vents, fans, etc have to be covered. They're trying to identify how leaky the property is without these being taken into consideration.
Are vented ridge tiles a requirement for Building Regs?
No, and they look shite.
What about Lap vents Roger?
No amount of membrane will stop this situation without correct ventilation and correct installation of insulation
Was told by roof vent supplier that we could NOT over ventilate a roof.
Yes they sell roof vents.
How do you properly insulate a hot roof ( cathedral ceiling)
Hi im doing a flat cold roof can you recomend vap0ur membrane for the underside of the joists and an abutment detail please thankyou for your time Roger ...
Thanks Roger. planning on plasterboarding our loft space for storage - do the same principles apply? Would a vapour barrier behind the loft plaster be a help or a hindrance? I tend to think it would help after watch your video.
Plasterboard, for storage space? Someone's doing well for themselves...
if using foil faced pir insulation you can tape the joints to create a vp and i would recommend at least a 50mm air gap and a dry ridge system
and fascia vents if boarding to the floor, if boarding to a dwarf wall (ashlaring) then tile vents would suffice
Vapour barrier yes….a vapour control layer no ( Vcl )