How to repoint paving slabs
Вставка
- Опубліковано 1 жов 2024
- In this video I show and explain how to repoint paving slabs.
This is really useful when the mortar which holds the slabs together has either cracked and crumbled away, or simply become tired and full of weeds.
It's crucial to scrape out all of the old mortar and any soil/muck which may have slipped down in between the slabs - you ideally want to get to the sub-base, or 5cm deep, whichever comes first.
The mortar mix should be made use 4, 5 or 6 parts sand to 1 part cement - you can choose the strength based upon the colour you want. You don't really need to add water, as there's plenty of water already within the sand.
Builders sand or paving sand work best - avoid using sharp sand, as this has lots of grit in it which makes the mortar look scruffy and course to walk on.
Here is the kit I use:
Bosch Professional Combi Drill and Impact Driver with Two 18V 4.0 Ah Batteries amzn.to/2owE0mK
Bosch Professional 18V Cordless Circular Saw with 2 x 18 V 5.0 Ah Batteries
amzn.to/2IGTwDv
Bosch Professional 18V Cordless Multi-Cutter with 2 x 18 V 5 Ah Batteries and 16 Accessories
amzn.to/2AYPOAM
Bosch Professional 18V Cordless Jigsaw with 2 x 18 V 5.0 Ah Batteries
amzn.to/2IDgTxA
Bosch Professional GAS 35 M AFC Wet/Dry Extractor
amzn.to/2p5iPbj
Bosch Professional GMF 1600 CE Corded 240V Multi-Function Router
amzn.to/35komvb
Occidental Leather 5089 LG Seven Bag Framer Tool Belt
amzn.to/2OAjlc4
Occidental Leather 5355 Stronghold Comfort Package
amzn.to/2VuRF9U
Hikoki Nail Gun
rover.ebay.com...
Bosch Table Saw & leg stand
rover.ebay.com...
Damp Proof Membrane
rover.ebay.com...
18mm Chipboard Flooring
rover.ebay.com...
I am redoing mine 20 years after I first laid patio. I used this method and it failed within a few years, so now doing it with a wet mix 3:1 ratio. Patio is 4x12 meters. Backs in bits.
You asked so. Sorry in my exp dry mix pointing don't last will crumble be patchy not durable within a few months. What I do is mix with enough water so that it's like a crumble mixture. Use pointing trowels to work in brush up afterwards. Next day it's solid sound. Will last years. The art is to get sweet spot between enough water to bind but not enough to stain. Landscaper 20 years
Thanks mate, really useful to hear that. As it turns out we had a bit of rain which rolled in over night after we laid it. I went back a couple of weeks ago and it was set like rock! Hopefully it lasts...
When I did landscaping I was taught by my boss to point with a wetter mix. Falls in the cracks nicely and presses itself down
Can you come and do mine please ?
@@OfficeBoyBuilder
Been a landscaper for many years we have done it that way but dose not last. now we use wet cement (sharp sand) clean with a sponge .when we are laying slabs we point as we go now so we have a strong bond and save time
What brand (types) of cement & sand and use 4 sand to 1 cement? Mix well, no clumps & wipe off excess w/ sponge, correct? MANY THX
Any brand will do really. I've used blue circle cement which is good. Any builders sand will work 👍
I would consider that too dry, breaks easily after a while. I use a wet mix, not sloppy, pack it in with the thick end of a bit of fencing feather or piece of wood, sponge the cement off the edges, and if I’m feeling super good, go over the surface with water spray bottle, just enough to seal in all the edges. Sets rock hard for years, no weeds.
Agreed
Yeah we add more water to the mix than that. which is a gaged 3/1. and we point it up with a rubbing in iron .
@@davidknell8831 On the ground, it should be 2/1 not 3/1
@@CyberWolfVR depends who yr asking I guess! Because everyone I know it’s a 3/1 ! That’s not my opinion it’s a trade fact
@@davidknell8831 It is an opinion when you have different trade opinions lol
Alkali means high pH, >7 is alkaline.
Cheers.
If a material is highly alkaline, I would have thought the ph would be above 7 rather than “low” ph as mentioned as low ph is towards the acidic end of the ph scale. Am I missing something obvious.?
You're right. I just got it the wrong way round...
Really helpful and clear advice, just what I was looking for. Thank you so much for sharing.
Cheers mate, glad you enjoyed it and found it helpful!
50yr old mum here, thanks for the clear no nonsense advice, gonna try this myself on my little patio.. Will hopefully save me hundreds.. Thanks guys
You can do it! Super easy and low mess/clean up 💪
@@OfficeBoyBuilder great video!!! I want to do this. with a 4:1 mix. do I use sharp sand , or builders sand. Or dried sand? you didn’t mention this on your video to help people.
Builders sand 💪
@@OfficeBoyBuilder thank you! do I leave it a day or two to spray it over with a watering can ?
@user-cv3wq7pt3f yes indeed. It depends how damp the sand is to begin with, if there's enough moisture in the sand, you may not need to add too much more than a light sprinkling with the watering can.
I’m saving this video for future reference. So easy and informative.
Will lift during bad weather and time, best to mix it up wet and keep it tight, then ram it in with either a 10mm or 12mm steel jointing iron, and strike it off?
How do you make up a wet mix and what do you mean by strike it out? Thank you in advance
@@Paul-mz2dq Just mix up your 4&1 sand and cement mix, with enough feed-up water to bind the mix together.
You can then trowel the mix over the joints, and use either a steel jointing tool, or hard wood jointer to press the mix down into the joints and finish off flush.. Using a tight mix stops any staining off the pavers/flags, and wears better over time due to it being compressed by jointing it up..
@@Paul-mz2dq Feb...
After watching your video I feel confident I can do my patio project! I’ve even taken notes! Really helpful thank you!
You've got this! ☝️💪😎
I would generally use a 3 to 1 mix of sharp sand for pointing or grouting great work still love it 🔥
Very interesting because my memories of my father doing some bits in the 60s or 70s was a very messy job with sticky wet stuff all over. I have a vast patio area most of which needs redoing - sigh.....
Pointed 1000s metres of Indian sandstone slabs, I generally mix 4 to 1 slightly damper than your mix, pack it in tight, then use a marshtown brick jointer to finish it of. Never ever do it if rain is forecast 😳 especially on sandstone 😱
Far too dry lads. Needs some moisture in before you pack it in to help it stick.
Best consistency is the same for bricklaying . 4/1 mix and a touch of plasticiser / fairy liquid .
So today was the day I did the patio, so easy and left looking very clean. The brushing sideways is so effective. Thank you.
Great to hear!!
If you like unstable paves sure do it .. best to put it in wet and ram it in..your paves will lock together stronger
Yeah that’s the best way just more time consuming it does go off okay but ide use the mist on. A hose pipe to wet the area after allot of people use dry mix it’s not the best but it does the job
Good luck doing that without staining the hell out of your patio!
Pack in with my arthritic fingers? No thanks. Use a 10mm pointing trowel. That mix is way too dry. Semi dry mix is best, sometimes called a 'biscuit mix' looks a bit like short crust pastry dough after you've rubbed in the butter. It's starting to clump together but doesn't stick to the paving slabs.
Amazing. You have no idea the time and struggle you have prevented.
Question.
Wouldn’t it be better to lightly sprinkle water on it then cover it with plastic sheeting for a couple of days so it cures properly?
Not a criticism just a question?
Yes that can work too, and that does work well. We knew that forecast so worked with that..
How much should I expect to pay to repoint per sq metre please?
Great example of dry pointing. At what stage in the repointing cycle do you clean and or power wash the paving slabs themselves (noting the black spot and general condition from the video), mindful of the integrity or relative weakness of the new joint material (days / weeks / months?) if then in place? Thank you.
What a helpful detailed video. Exactly what I was looking for. Top job!
Got one question : Do you have to have guttering (as I can see the drain in the video) when you are sealing paving slabs? Because when you seal it, the water has no where to go.
Thanks! Glad it helped!
A patio should always have a fall on it, to help with water run off. Small amounts of water will seep through the sand and cement grout.
I always swept it in and used a jointer. keep pressing it down until it wont go anymore.
Need the joints damp and the mortar barely damp.
If you put a hose on that patio now, you would end up as you started.
That's what I am going to do.sweep it in..push it down....and hope for the best.
the eternal debate between dry or wet mix for repointing.
Each to their own, but dry is quick so many trade use it a lot for obvious reason.
However... now we have resin based filler options that are just as quick/easy to consider as well (£££!)
Cheers not done any in a while and me grandma wants some doing just needed a refresher
I have 11sq metre area of patio that needs repointing. Would appreciate recommendation of quickest and easiest way of doing it please. I am not concerned that it lasts for many years just that it looks better now.
Hello, thanks for the video! Quick question what sand and cement should I use please?
Sorry but this is no good pal soon crumble an Crack. Best of doing slurry mix and do it that way
how many bags of cement and sand and what sort of cement ? is it quick drying cement ive never done this so havnt got a clue ?and i dont have one of those hoovers so how would i get the stuff out of the cracks ?
If your weather goes below 32deg. Don't ever use a dry mix like this.. it will not hold up for very long
I’ve looked at this video and it has helped me at least given me the motivation when the weather improves. Is there a ready mix that saves on the mixing process? If so please PM me with that advice.
What sand did you use? Sharp sand or just builders sand?
Builders sand - sharp sand wouldn't give you the consistency you need
Thanks for the video. I need to repoint some cheapish Bradstone paving slabs that were originally done using a dry mix. A recent power wash blew a lot of it away so I'm left with gaps of varying depths. It would take me a month of Sundays to remove what's left. After reading some of the comments below, I'd prefer to use a wet mix. Three questions: 1. What's the minimum depth of new mortar I can put over the old? 2. Is there any glue that would help where it's very thin depth? 3: Are there any ready-mixed mortars you'd recommend as I have very little space to work in?
Hey, I'd be very cautious about trying to stick new to old...cement never stops curing, and so if you have two different ratio mixes on top of each other, they can react and break down faster.
It's worth allowing at least 2 centermetres or more really...the deeper the better, to allow it to pack in and hold.
I don't know a wet mix, but there have been a few other comments of people recommending a wet mix that you sweep over the paving slabs...maybe take a look and see other recommendations there 👍👍
Is it going to set really hard without water? Is weed gonna grow like with sharp sand only?. Will it get pressure washed away?
Thank you for Very useful video.I am certainly going to try and repair my patio .
Firstly, you sound just like bear grylls 😂 secondly you said rinse and repeat. What do you mean. Do we need to add water after pointing, or just leave to cure then do the watering can sprinkles. Thanks doing it this week myself
Rinse and repeat is just a turn of phrase that means "do it all over again"...you don't actually need to rinse anything down.
Best of luck!
Semi dry mix is much better.
The mix is to dry it will crack after a while 🙄👎 best way to pont is 3 of soft sand one of sharp one of cement so it's a 4 and 1 mix knockout semi-dry is in between wet and dry ad little touch of SPR then get a gauging trowel feed the sand and cement between the joints then use your finger trowel to packed in. no take longer but must better job 👍
3 years on, it's as solid as a rock.
So no water is added to the sand and cement mix? And it sets
The sand needs to be damp. But you don't add lots of water like you would if it was cement
Wow, you have really helped me out. I have just had Indian sandstone slabs laid by cowboys !! They used
SIKA FAST- FIX SELF-SETTING PAVING JOINTING COMPOUND which they did not apply properly so I have scaped out and will now do what you have done I will let you know how I get on tomorrow. Thanks for sharing a very informative video.
Sorry to hear that! I hope the fix worked as well for you as it did on this patio! 🤞
@@OfficeBoyBuilder Hello I did what you showed us in the video and it worked great Thank you once again for sharing your video
That's awesome! Congratulations, I'm glad it helped 👍
Will you be able to pressure wash this once its fully set? - I have indian sand stone for my patio and i've got holes in mine everywhere, i'd like to be able to repoint mine but be able to pressure wash it.
Thanks :)
Yes you should. Sand and cement sets really strong. After 10 years or so it's likely to need repointing due to frost/ice slowly breaking it up, but in the meantime it should be fine for pressure washing.
@@OfficeBoyBuilder thanks for the prompt response! I know what I'm doing next weekend then!!
No.
I went with a resin based product for our new stone flags, newer had any successful long term results with cement mortar but that could be me, a DIY er🤡
The resin is now two years old and still like new with no problems.Tine will tell though.
What kind of resin
Thanks for this video. I have just had my paving pointed and it’s cracked and come out after 2 days! It was a Wet mix though.
Any ideas why that happened?
Gutted as a family member done it and they obviously don’t know what to do.
I don’t have experience with pointing or laying flags. So not sure myself so I am lost.
I am thinking about doing what you done. Concerned about staining flags?
Been told to use silka resin?
Was this building sand and concrete? What was you mix
Thanks for great video
Sorry to hear that, sounds like they've under mixed the cement perhaps? Hard to say really.
Normal soft builder sand + cement is a great way to go. Damp it slightly and you can carefully pack it in, no worries about staining.
Alkali is high ph if you're trying to sound smart get it right
You're about the 4th person to correct that. If you're trying to be smart, be original
would you recommend using a pre mixed mortar product? not confident at mixing my own mortar!
Building sand or sharp sand
Should not be using your fingers and best to do a wet mix
Good job
Although I would have though you d use sharp sand rather than building sand
Waste of time, all that prep was good, but the mix was too dry.
Wetter and strike in, time consuming, but solid.
Thank you for such an informative video. You make it look so easy, so I will get myself some sand and cement this weekend and give this ago, thank you
Best of luck, you can do it!
Hi
I've pointed my garden with builders sand and cement 4/5 to 1 and it looks yellow. How do you make it to look grey?
Cheers
More cement...you wouldn't need much, just a dusting.
People have said to lightly sprinke an hour after
Thanks for the video, did mine a week ago and left with lots of cement stains on the slabs, can't understand why as washed and brushed it off afterwards. Any tips on how to renove the stains? Thanks
Sorry to hear this - it really depends on the type of paving you've got, but I hear that CSR Cement Stain Remover can be good. Worth researching exactly what slabs you've got, just to make sure you don't have any issues.
Good to know I need to remove the old point first !
My ants have removed mind last 5 years. So de weeding and using ready to use.and sweeping in.
Thanks for your video very informative weather its nice today I'm going to crack on. 😀
Mix looked like 2:1 quite grey.
Sorry I have one more question. As I was cleaning today I saw under my door a black cloth and dry sand. What kind of cloth is that. I have landscape fabric can i use that?I live in Calgary and because of problem of the paving the door gets jammed throughout winter. In some places the paving stones have a v shape.
I'm guessing it's a weed barrier/landscape fabric, but I honestly don't know!
I've never seen pointing done with a semi dry mix that's has lasted much more than a year I always wet point takes longer but is worth it because it will last years providing the slabs have been layed correctly with no rockers.
how do you apply the wet point mix? i did some dry pointing last year, basically the same as this video, has started to fall apart in areas already!.... in the shaded areas where the mix stayed damp longer it set much harder.
@@kanhdahar2 use a mortar hawk and slicker.. takes time but is the proper way.. this is nonsen5
@@hmg8915 ive used a dry mix and it only lasted a year, please dont use this method.
Great video, just what I was looking for.
What sort of sand do you recommend? 0/4? 0/2? Kiln dried?
Thanks.
Builders sand is best ☝️💪
@@OfficeBoyBuilderThanks!!! 😊
Too dry
If it is alkali it would have a high p.H. , above 7, just saying!
Yes, I got them the wrong way round!
During the demo of applying the mix and compacting it, you said rinse and repeat. Can you explain what you mean by this please. Thank you
Sorry, I meant just do it all again - definitely don't rinse it with water...!
@@OfficeBoyBuilder thank you 👍🏽
I've York stone paying, is it possible to obtain a mortar mix that compliments the colour of York stone?
I believe product's like flowpoint have different colours to them...I haven't used it before but have heard good things about it.
If not, changing the amount of cement you use in it will make it darker or lighter, depending on whether you add more or less.
How to do a patio with bear grills
great video guys,
How long do you leave it before being able to jet wash the patio again?
The longer the better... cement never stops curing, up until the point it gets broken or damaged. Ideally you'd jetwash before you re-point, and then use it as a method for removing the old stuff.
Minimum of a week or two though
Hi
Thank you very much for the video.
I have the same job repointing the patio front and back of the garden .
I thought water is needed to mix the sand and cement before putting the mixture down the gap .
Please let me know .
Thank you .
Teresa
Best of luck with it!
It really depends how wet the sand is at the point you make the mix. If it's bone dry sand then you'll need to add a bit of water to get it right.
If the bag is already wet then you won't need to add much, if any.
There's a bit of feel to this - you can always add a little more water if needed, but it shouldn't be sloppy!
Is that all you mixed in with sand and cement to get that colour??
Yes, no additives or colourants were added.
how much is that job in the uk
What sand do you use please
thanks, great video. I have one question, my slabs are dark grey almost slate coloured. How do I get the grout to be roughly the same colour and not too light ?
You can use more cement and less sand - not too much, but the pigment in the cement has a strong colouring
Looks great, now to do mine!
Awesome.
Sounds like bear grylls talking lol
How long will it take to dry enough fully?
Around 1-3 days, give or take - depending on the weather
Thank you, sorry I hadn’t fully explained, sounds awful but I’m going to paint the patio, so probably should wait longer? Praying for a bit bank holiday sun 💪
Once it's fully dry you shouldn't have a problem, but perhaps give it 3 days so it's definitely cured. Hope it comes out nicely!!
Crumbly bits 😅🎉🎉🎉
How log did it take to do this job mate? And what size in square meters was it? Cheers
It took 3 of us 1 day, but really not sure what the size of it was mate. Sorry!
@@OfficeBoyBuilder thank you for answering
I’d be interesting how would you take the existing grout out? What would you be using to do it efficiently?
Honestly anything you can get your hands on! A manky old chisel. Or better still a cold chisel and hammer would do it, if it's really tough. Sometimes if it's a very old, soft mix, a stiff wire brush would work.
Would this grouting withstand power washing?
Once fully cured, yes.
Obviously as grout gets old, it will break down, mainly through frost and ice damage, but that takes a number of years
We washed after 2 days and most of the sand come off. Also cracks appeared. Any suggestions
Hmm...it could be a number of things; perhaps check the ratio of sand to cement. Also check the depth of the pointing to ensure it can really bed in.
If that still isn't working (on a small test area), try a product like flow-point.
@@OfficeBoyBuilder thank you
Great and helpful video, thanks!
was 2 years ago now, how did it hold up?
I’m fact ignore this. I see you did a follow up!! 👌
A great and helpful video. We have blocked paving (pretty ugly really) however, would you recommend painting the slabs with masonry paint and would we do this before the repointing? Thank you, Rachel
Thanks, I hope it works out for you too!
Painting slabs is really tricky and depends on the amount of wear and tear it will have...! If you're out there a lot it will end up scuffing. Masonry paint is designed for walls more than high traffic flooring. You're better off with an epoxy resin based paint for that really, and then do the pointing afterwards for a nicely contrasting (or complementing) look 👍
my needs repointing plus i don't have any dpm membrane underneath my slabs can rainwater penetrate through slab gaps and damage building foundation and cause damp?
DPM underneath isn't really needed when you have large slabs like this. It's best practice to put it down if you're starting from scratch, but you wouldn't rip it up to put a DPM down.
Also, rain water cannot damage foundations. Water can cause damp, but that's because of a lack of DPM between the foundations and the wall, not because of the slabs (UNLESS, the patio slabs sit higher than the DPM, in which case you will need to remove the patio and dig down and then lay a new one)
@@OfficeBoyBuilder I just have patios without anything underneath just soil when it's raining the water found a way to come in the corner wall of the kitchen is this cos of lack of dpm membrane and other things?
It depends how high your patio is. It could be driving water into the house, if the patio is angled towards the house slightly, or it sitting above the DPM layer in the brick wall. You'll need to get someone to come and look at it.
Having a DPM under your current patio will not fix your problem.
@@OfficeBoyBuilder where abouts are based in the uk?
South East London
Should be a hand model 🤣
What type of sand did you use. Sharp, building, dry kiln?
Just normal yellow builders sand 💪👍
@@OfficeBoyBuilder thanks
What cement please
Thank you for the tips.
This looks well-doable (it would, in the hands of a professional!) so am hoping to have a crack at my own, with thanks! And thanks hugely for your list of tools and materials, much appreciated! 🙂
You can do it!
Thanks, this is really helpful
Who laid that patio, cross joints galore.
No idea - it was laid when we found it...just came in to re-point!
Thank you for this, just what I was looking for.
Just what i was looking for ❤️
Great! I hope it helps 💪
Hi what materials do I need from shop please ?
Builders sand and cement 👍
Legend, great video! Will be repointing when the weather dries up. 😂
You got this!
ill give it a go,ta much.
Thank you. Just doing this now on my end to prevent weeds
your 4 to one mix do you had water? at the start
No it's a dry mix...moisture from the ground will set it off
was that just sand cement mixed dry?
Not quite...the sand has a lot of water trapped in it already, as most soft builders does. If it happens to be a bag that is bone dry, then you will want to add a small bit of water to help it clump in your hand when you squeeze it 👍
So you don't need to sprinkle water over the dry sand and cement mix to allow it to cure?I I'm amazed that you can just leave it for a couple days and then lightly water it (or let the rain do the job). I assumed that you needed to water it as soon as you'd tamped it in: the sooner it is properly damp, the sooner it cures and can be walked on.
So far I've only ever filled the gaps with damp mortar (dry enough paste that it can be tamped in without staining the stones too much) and sponge off any staining ASAP. Dry-filling is probably a lot easier (less wear on the knees as I gradually fill each crack) but does it really set as firm?
The problem is that I'd be doing a patio that gets a lot of usage (it's the main way from the back door to the garden) so it needs to be capable of withstanding walking on it fairly quickly.
Yeah it works well bud - if you rewatch the video, near the start there's a little pop-up in the top right corner which is a link to a video I took 1 year later, of the same patio. It shows you how then mortar has come out and held firm.
Loads of comments here saying "it's no good" but they're wrong. It works perfectly well 👍
@@OfficeBoyBuilder I did a first trial this morning (just a few inches of one of the cracks, before I committed myself to a large area) and I had two problems.
You say that the consistency of your dry mix should allow it to clump together when you squeeze it in your hand. Mine remains a loose powder even if I squeeze it. Is that due to the cement:sand proportions being wrong. I'm using B&Q mortar pre-mix which unbelievably doesn't actually state the proportions by volume. Because the mix doesn't clump, even after I tamp it down, it is very prone to the lighter cement blowing off the top, leaving the heavier grains of sand behind.
Secondly, I found that the flagstones got stained by the cement. This is for dry stones and dry mortar mix. Brushing removed the excess mixture but left the edge of the stones stained grey. Because of this, I had to water the mix almost immediately (hosepipe spray on mist setting) so the cement that was staining the stones became wet and could then be sponged off.
I'll report back after a couple of days when the mortar will have cured as much as it's going to, to see it it has set rock hard or whether it's still powdery.
With a light misting of water or a light rainfall, how deep does the water penetrate to cure the mortar? The old mortar I dug out had only cured to a depth of about 10 mm, and below that was uncured sandy dust which was probably a mixture of sand and the base soil, maybe mixed by any insects that had burrowed in it. I presume the dry method, absorbing atmospheric moisture and/or a misting from a hosepipe relies enough water permeating through the dry mix to a good depth before the top "skin" has cured and sealed the surface, preventing moisture getting deep enough to cure the mixture deeper down.
I'm sure the technique works and that I'm not doing it correctly.
If it's not clumping when you squeeze it, the chances are your mixture is too dry. My bag of sand was really quite wet which allowed a decent amount of "hold".
That also explains why the cement is blowing off the top and staining the edges.
Try wetting the sand so that when you hold it as a fist of just sand, when you tip it back into the bag, your hand is lightly covered with wet sand, and the fist-full gentle breaks down to a pile when it hits the rest in the bag. That should be sufficient to chemically trigger the cement, and then the sprinkling of water on top at the end will seep through to help cure the whole lot
@@OfficeBoyBuilder Ah, so the sand has to be dampened first. I hadn't realised that. I imagine that rather prevents the use of pre-mixed sand and cement, because premix has to be completely dry until you want to use it otherwise it will cure in the bag.
Shame, as I've just bought 50 kg of premix to repair the damage to the mortar caused by pressure-washing the stones, exacerbated by the mortar being old and having already cracked all over the place.
Looks like I'll still be using the wet method, though I'll bear in mind the dry method for the future. How much latitude is there in dampness of sand? Presumably if the sand is too damp, it will form into a paste when mixed with the cement, and that won't brush into the cracks between the stones. How much experimentation did it take you with the amount of water to add to the sand to get it so it produced a powder that clumped rather than an conventional wet-mix paste.
Is my problem with dry cement staining the dry stones due to the sand being so dry that some of the cement is loose instead of being bound to the grains of sand?
I'll persist because if it is possible to make up a mixture that can be brushed into the cracks and yet is damp enough to be clumpable so it doesn't just blow away in the wind, then this is so much easier than trying to ram damp mortar down the cracks without staining the stones.
My bags of sand were just wet from the rain so I didn't add any more water to it...it's not an exact science, but more of a feel thing that you get used to.
Cement just stains, it's less to do with the stones, than it is to do with the nature of cement itself...!
I've not worked with pre-mix before, but you may be able to dampen it and use a paddle-mixer on a drill to get it mixed round enough?