First of all you dont need to install a surface dpm if your floor reads less than 75% relative humidity on a hygrometer flooring meter. You may choose to buy one to try and miss the costs of installing dpm when its not needed after all. If not on with the info. 1- Subfloor should be cleaned and as dry as possible. 2- Prime floor with neat p131 on non absorbent floors and water down on absorbent sand cement etc (approx 1-3 mix) 3- Next self level the floor with an acrylic levelling compound. 4- When dry (24hrs+) you can give first coat of dpm (F75) 5- Second coat of dpm (f75) when first is dry. I like to put this down when the first coat has a very slight tacky surface on it but not wet of course. Depending on temp about 12 hours or so later but within 24hrs. 6- Leave second coat for a full 24hrs to cure and then prime again with neat p131 primer. 7- Self level the floor now with leveling compound of your choice. I would use a water based product (red bag) or acrylic levelling compound You will need- Primer - P 131 neoprene primer Dpm - F75 ( you need 2 coats and cant part mix tubs) Levelling compound - acrylic for base and your choice for top finish These are basic instructions to give you an idea of what you have to do. Full instructions will be on the products and available to you where you purchase your products. You can leave a post for me if you want any more info.
I thought 131 wasnt suitable to use under a dpm? When did that change? If you are sticking down a engineered wood floor and the rh is below 75% do you still need to use a dpm?
i will answer this properly in the morning. If you look at the date of the first post you will understand things have changed over the last couple of years.
131 is o.k to use under a surface DPM providing the subfloor already has a DPM in it. If the subfloor does not have a working DPM you can use 131 as it will break down. However, it is no longer recommended to Use surface DPM's on subfloors with no DPM under the base. You are now supposed to dig the floor up and replace with new to building regs. And no you dont need to use a surface DPM under a engineered floor if the moister is below 75%. On solids you want the moister to be below 65% which is almost impossible so then you do need a surface DPM.
In reality that isnt gonna happen. No way someones gonna rip up an old floor to replace with new upto spec stuff, not in this economy. The dpm would work well enough tho wouldnt it matt?
I have never had a issue. Again its one of them things tho. All depends on the house im installing in. For instance, if the house is built on flat land or at the top of a hill the water pressure will be a lot less that is trying to push its way up through the subfloor. Now if you have a house at a bottom of a hill or land around the house that is higher than the footings of the house, you will have more water pressure pushing its way through the subfloor. If this is the case you have alot more chance the Surface DPM will blow. Just like how a swimming pool should not be left empty as the water pressure will lift it out the ground. Also, there are alot of primers now that can no longer be used on damp floors. A few years ago most primers could be used.
I'm going to a job tuesday near welshpool and they have half new concrete an have old quarry. Was going to do 2 coats F75 then prime and 300HD Or should I tell them to take the quarrys up an maybe have ashpalt down. then dpm where it meets concrete
how 'new' is the concrete? how thick etc? Could always just price it 'the right way', give them advice and take it from there
Done it today, long day that.left mine at 7 and got job in Wales at 8.15, 2 coats of f75 with accelerator, prime, 300hd. Rang Matt for bit of advice on the waiting time to put each coat on, thanks Matt for that. Van gogh going down on Thursday
Yeah Mike about 3 hrs, had to put heating up to speed it up. 2nd coat took about 4 hrs though. Primer when off quick cause of my fan
What system do you do Matt over old ata adhesive which is what is on the sub floors on a lot of jobs I go look at. A lot of confusion over this now.
The subfloor should always be cleaned. But if i was in my own house ... ... ... i would put down Eco prime T primer. Then use Latexplan , then use 1K turbo Dpm. I would then stick direct to this. But if my first skim was not the best i would finish off with a secound layer of screed on top of the DPM, i would use Fibre plan compound. All these products are made by Mapei. Like i say tho, i would only do this in my own home !
