Hi all, I levelled part of a floor the other day for a customer who is having karndean laid. Half the floor was ply over boards and the bit I levelled was concrete. I used mapei tradeplan slc, the two part system. The customer has phoned me tonight saying cracks have appeared in the slc. Is this a problem? He says there only hairline cracks so I'm going to look tomo. I primed the floor first using primer g. Any thoughts?

A small bit of movement in the ply while it was drying out from all the moisture from the slc

I didn't slc over the ply though, I was just bringing it level with the ply part of the floor.

Did you use a roller to ease out any air bubbles etc?

I'll try again

Shrinkage

I had the same prob on a concrete floor last year with that leveller..

Never used it since....

Didn't use a roller.

Spiked roller makes no difference unless you need no bubble marks.

How thick was it laid
Never had an issue withit at all.

Didn't lay it thicker than 10mm which is what it goes up to. I need to see it. I'm just worried that the guys who are laying karndean won't be happy with it.

I was told by a kardean layer that this particular leveller should not be used greater than 3 to 4mm.. he loves the stuff but would not go thicker as it cracks he said..

I stick to fibre plan or pci hsp34 now

self levelling compounds are no different to backing plasters or primers...if they are laid too thick and the substrates pulls in too much of the mositure then they will crack, simply as that .......control the substrate, use the correct leveller at the recommended thickness and you will have no issues...apart from unstable sub floors, but thats another topic

ed

I have a friend who wants an old cobbled cellar floor levelling, was thinking fibreplan??

I prefer single component fibre reinforced levelers like weber floor flex or fibreplan.

How long had the concrete been down before you layed the SLC? And do you know where abouts in the floor the cracks are coming through?

I have been using Levelflex fibre slc by TA. Good stuff imo

so what do the experts think,out of interest, will it be ok with hairline cracks?

Originally Posted by stevee

so what do the experts think,out of interest, will it be ok with hairline cracks?

Hi stevee, I had this happen last year. Rep came out and said it would be fine, he said it was just shrinkage

so what do the experts think,out of interest, will it be ok with hairline cracks?

Impossible to say without seeing it.....

When you tap it does it sound solid?Have you tried chipping a bit up to see if any loosness spreads?

As above.. do a tap/sound test on it.. as for shrinkage.. i wouldn't use any levellere than was prone to cracking with shrinkage..

That is why i only use the fibre enhanced ones now.