Error in preparing subfloor with self-leveling compound

[DavidA1982]

Hi all,

This is a very helpful forum but I wish I had found it before today...

I am trying to put in a new floor in my kitchen this weekend. The subfloor is a solid slab that is mostly level (although in parts, just earth). There is no damp proofing at all and the floor was a bit damp. There is no damp proofing on the floor. It did not cause any problems before (I took off the old screed and tiled floor already). I went to buy compound to level it yesterday, and now it looks nice and level today. I was going to paint on a damp proof membrane today.

But now I have just seen this thread //www.diynot.com/forums/viewtopic.php?t=80131 and think I have put in the wrong compound. I mixed my compound with water and the thread says that I should use an acrylic based compound? The thread says to use an acrylic compound but now I have already put down a water based one, how bad is it?

What do I do now? Do I have to take out the compound I put in yesterday? Can I paint on the liquid damp proof membrane on to it anyway? Can I pour an acrylic leveling compound on to the one I poured yesterday and then paint on the damp proof membrane? I will then put on another layer of compound. For information my final aim is to put down tile backer boards and tiles on top.

I am a bit concerned anyway because there is no damp proofing in the walls either. There have been no problems with damp in the floor or walls before. Is it possible that I will cause a problem in the walls by putting down a damp proof layer on the floor?

I would be very gratful for any help!

 

[dazlight]

Hi Dave, what screed did you use. Was it moisture tolerance?
Prob not if it's a water mix. What flooring will you be laying?

 

[DavidA1982]

Hi Daz

Thanks for responding.

I used a cementitious compound, mixed with water. I planned to paint a liquid damp proof membrane on to this, and then put down another layer of compound, then no more ply boards, and then tile. The only reason I put down this compound was to give me a nice level surface to paint the damp proof membrane on to, but I have now read that I should have used acrylic-based compound.

I am now a bit stuck; I do not want to continue with my project until I know whether I have made a mistake, and what I should do about it. Until I know this I cannot really continue. The shop I bought the compound from just say that they've never had a problem with anyone complaining about their floors breaking up. But I will take the advice from people on here - if i have done it wrong it is easier to fix it now before I put down more products!

EDIT: if it helps, I used this product: http://www.theunderfloorheatingstor...nd-889-p.asp?gclid=CKfw_o3-iLICFUNkfAodiVAAmg

(although not from that shop). It is described as latex in this advert but I do not know why - I mixed it with water and the bag does not say that it is latex.

 

[DavidA1982]

Also, can anyone tell me where I can pick up an acrylic based compound? All of the places I've been to have never heard of it. I've also been told that latex is used now instead - but from what I can tell, latex would be no good here i.e. under the DPM.

Thanks

 

[crazydaze]

Give F-Ball technical services a call http://www.f-ball.co.uk/technical_support.asp

They will know what to do next.

 

[dazlight]

If you are laying ceramics down you won't need a dpm mate.
You should be ok With that screed it's good gear.
As long as its got a good bond to the sub floor.

 

[DavidA1982]

Daz, Crazydaze,

thanks for your help. I had to get the floor down today so spoke to the technical departments at a few suppliers this morning, and they advised me to go with Arditex NA, and Ardex DPM 1 C as a damp proof layer. I'm putting down quartz tiles ultimately. The technical guy at the supplier of the compound I put down said that they are quite moisture sensitive, and whilst he said that the compound could be fine it is obviously not designed to sit below a dpm.

So I decided to chisel off the cementitious compound and put down the Arditex NA today. I'm putting down the DPM tomorrow morning (not looking forward to that, it looks difficult to get it to a uniform thickness), and then another layer of Arditex NA, and then no more ply. It was probably creating work for myself and a bit OTT but I'm happy that the stuff I've got down now is the right stuff and it means I can crack on with the rest of the project knowing that I've done what i can to get it right!

I have to say, I was really impressed with the technical help that the guys at the product manufacturers gave me. I was referred from one company to another, because the technical guy at one said the product at Ardex was best suited to my needs, and they spent a lot of time talking to me about it to establish exactly the correct course of action.

 

[dazlight]

Nice one Dave.
Top gear Ardex.
Bit pricey but works well.
The dpm is spot on.
Tip to lay that is trowel it on with a A2 notch trowel, then roll it with a foam roller head.

 

[dazlight]

Like this
http://www.floormart.co.uk/products/18cm-Spreader-Handle-A2-.html

 

[DavidA1982]

Thanks Dazlight. The guidance on the technical datasheet says a suitable V notch trowel so it is good to know exactly the one to use. Really appreciate your help.

As regards the price: you are right! I did gulp when they told me the price at the suppliers, but as long as the floor is solid, sound and damp proof it will be money well spent!

 

[DavidA1982]

I find it irritating when people start a thread like this and never let people know how everything turned out, so just to update the people who helped me (and more likely, novice DIYers like me who end up searching for Ardex DPM on this forum):

I put down the DPM 1C today at about 7am. I wanted to get it down early so I could get another layer of compound down on top today, but also because it's a bit cooler early in the morning so the DPM would be workable for a bit longer. It is lovely looking stuff, I wish my floor could end up looking like that. It's like painting the floor with glittery black glass. Stinks though, and I would not want it anywhere near my skin. Anyway, I used a trowel like the one Dazlight suggested. Did the trick. I was a bit worried that it was a bit thin when I was trowelling it due to the serration ridges, but the roller sorted that out quickly enough. As I'm a novice I put it on a little bit thick to try to avoid any pinholes or breaks, but all the same it was easy to work with. In my case it was the roller that ensured the cover was continuous and complete, the trowel was more to get an even application of the stuff and spread it out evenly. I also had my dad help me with this. We did the floor in about four or five separate pours and worked as quick as we could; I trowelled and my dad was on the roller. I'm sure a more competent DIYer could do it easily alone, but for novices like me it is definitely a two-man job.

Anyway, it took about 9 hours to harden, which was a bit slower than I was hoping. After about 6 hours it was still very tacky so I spoke to the tech guy at Ardex who was very helpful; he just said that I might not have got all of the hardener in to the mix; or that it might take a bit longer because it was a cold day. I mentioned that I put it on a bit thicker than the 250-350 micron depth stated on the technical datasheet (how do you even measure that sort of depth?!? That's a third of a milimetre!?!), but he said that a
if anything, a thicker layer should set more quickly as it is an endothermic reaction which causes it to harden. Or something.

After 9 hours, I put down a second layer of the Arditex NA. Spreading compound over the DPM is an absolute pleasure; the surface is so glassy the stuff just runs so smoothly. This was easily the most enjoyable part of the weekend's work. The Arditex NA does set very quickly though; I had to work as fast as I could to get it all poured, trowelled and spike-rollered before it hardened. I was a mildly warm evening (maybe 18c), but after literally 20 mins it was more like a paste than a liquid. It is amazing how fast that stuff sets - I could walk on it 3 hours later.

Finally, one rookie error to give the pros and experienced guys something to laugh at: After using the roller on the DPM, I put it on a concrete floor in an adjoining room that I am also working on. I forgot about it and when I found it about 6 hours later, it was glued solid to the concrete floor. I did manage to lever it away a bit with a crowbar, but the concrete stuck to the roller rather than the floor! I'll attack it with my trusty SDS breaker tomorrow, but at the moment it's a gloriously black and shiny statue in the dining room. So today's lesson is: if you are using an epoxy resin DPM, anything that it has touched needs to be got rid of quickly, before it makes a total mess of an otherwise-servicable floor!

 

[dazlight]

Well done Dave, glad it went well and thanks for posting how it turned out.
I most of used 100 roller heads this last year.
Good luck with the tiles mate.
Daz

 

[DavidA1982]

Right, another quick question:

I plan to put down aquapanel boards over my new floor before tiling, because:

1) they look like they would give me a nice flat surface to work on;
2) they bring the level up to exactly what I want to meet the floor of the adjoining room at a lower cost (and lower effort) than additional compound;
3) the installation instructions say that they can be laid onto concrete floors whereas hardibacker cannot; and
4) most importantly, I've already got them and I can't fit them in my car to return them and they are getting in the way.

Just a few questions on using them:

I'm going to use a flexible adhesive to stick them down because the instructions tell me to... but couldn't I just use a non flexible adhesive as I'm laying them on a concrete base? Last time I bought a 20kg bag of flexible adhesive it cost me £50!

Also, just how flat does my subfloor need to be before I put the boards down? I imagine that provided the low points are no more than, say, 1cm lower than the high point, the adhesive will fill the gap? Or do I need to use a patch repair product to bring up the low points?

And am I mental to be using them? I can't find many examples of people putting boards down over concrete subfloors!