Self Leveller Compound - Sweating

[vGolfer]

I poured some self leveller about 3 days ago in our new laundry. I had to raise the level approximately 20mm so I formed it up, primed the surface and poured. All went well - it was only about 2sqm - one of those built in cupboard type laundries out the back on a concrete slab.

Anyway, I checked this morning and the area was coated in condensation. The whole area is dry so I am a bit stumped as to what has happened. I am just going to put down some el cheapo Bunnings tiles, but I don't really want to start until I know what is going on.

Any ideas?

Cheers

[pharmaboy2]

hi,
depends on which one you used, I've used the $20 a bag stuff from bunnings, and never again - took a week to go off completely, the pro level is much faster curing and stronger.

Adhesives usually recomend letting a slab dry for 7 days at least before tiling, so I'd be conservative and wait as long as you can - water beading on the top for a day is not a bad sign, just a sign of waiting.

[vGolfer]

Yep, it was the stuff from Bunnings. I have used the Bostik Ultralevel before, but I couldn't be bothered driving to the place that sells it just for one bag.

Anyway, I hope it's OK by the weekend as I want to tile it soon.

[pharmaboy2]

I didnt tile it, but tried to move a fridge over it 4 days after laying and it did some decent damage - I ended ripping most back up and relaying with extra cement. I've laid tiles over normal cement after a few days, and typically tilers will pour their screed and lay over after the walls are done (2 days) but screeds have buggar all water in them, cf leveller - you'll have to make ajudgement on the weekend based on how dry it seems (leave a sheet of timber on the floor overnight - you are looking for dry timber in the morning to tell you its cured) - if its soaking wet underneath - thats what the tiles will be after you lay them.

[Trav]

I used some of that levelling stuff a few weeks ago. I could walk on it in a bout 2 hours and it was as hard as in a few more. No water beading on mine at all.

My advice would be to wait for a while. Pharmaboy is on the right track. Tape down a bit of clear plastic overnight. If there is heaps of condensation, the slab it too wet. That is how the flooring guys often get a rought estimate anyway.

Trav

[vGolfer]

Just checked again this morning and it was quite damp. Some beaded water on the surface.

Is iit possible to just go ahead and tile or do I need to wait until the moisture stops coming to the surface? It's only a small area and there will be no traffic over it at all.

[Trav]

I personally would wait until it is dry. It is not so much about the traffic over it as the bond btwn the tiles and the slab. If there is still water coming out would it affect the strength of the tile adhesive? I'd wait for a few days. 20mm deep shouldn't take long to dry. I can't believe it has even taken this long.

Trav

[mic-d]

It's just the water you mixed the SLC with evaporating out. Probably seeing the condensation because its a small poorly ventilated space. You could run a fan in there a day or two to get rid of the moisture faster. Nothing to worry about, just give it 7 days and tile with a cement-based flexible tile adhesive. It won't harm the adhesive, in fact it will slow down the drying out of the adhesive making it stronger.

Cheers
Michael

[powerbuff]

I'm putting floating floors down but the concrete isn't flat. I'm thinking of using some of this. Would the flooring go straight on top of it (besides the 2mm underlay..

Thanks