Problem With Extension Floor

[Kathyan]

About four months ago we had our un-used conservatory taken down and replaced with a brick built extension with toilet. When the wall was taken down between the kitchen and extension there was a difference in floor levels, so our builder put down some self-levelling compound to bring the extension up to the level of the kitchen floor. We then had vinyl laid throughout. Last week we noticed that the vinyl had started 'lifting' in the extension, so we had the fitters back to take it up at the join and all the compound had crumbled and come away from the floor underneath. The builder has been back to have a look but has no idea what has happened. There is no damp. The compound was suitable for up to 50mm depth but wasn't anywhere near this. The builder has suggested unibonding the floor first then re-levelling. Does anyone have any other ideas or suggestions please? TIA.

[The Builder]

How much is the difference between the two levels, Kath?

[Kathyan]

No more than 5mm at any point.

[The Builder]

Very rare for this to happen, Kath. If it was the original conservatory floor underneath, I can only think that the surface was contaminated in some way. There has obviously been a chemical reaction with the leveller.

Any one of products such as these should give no trouble.........

http://www.wickes.co.uk/Products/Building-Materials/Cement+Aggregates/Floor-Levelling-Compound/c/1000210

For the sake of 5mm, I'm surprised there isn't some kind of underlay that would make up the difference.

[Togo]

If it was a leveller that was mixed builder, do you think that they may have mucked it up. Using a drill and whisk type blade at a fast speed can aeroate the leveller and ruin it.

[Kathyan]

Togo, they were very careful how they mixed it! We did wonder if it was maybe a bad batch but having thrown the bags away we don't have any batch numbers. There were tiles on the conservatory floor which were taken up. I wonder if the adhesive residue might have something to do with it?

[Togo]

Right Kathyan. I wasn't ignoring an original poster, and think Builder has that covered as he always does. I just didn't want to give an opinion or reason that turned out to be nonsense to you. So just asked 'the man' what he thought.

[Kathyan]

No problem Togo.

[The Builder]

Haha Togo. You're too kind ;o)

Yes, a bad batch is always possible of course, but perhaps it was the tile adhesive. The trouble with these things is that we'll never know.

It does sound as though they checked the bag for mixing instructions. It really shouldn't be a problem though. Mixing with dirty water rather than fresh can cause problems, but I doubt if they did that.

The only other important consideration is the amount of time allowed for the leveller to cure before covering with a completely non-breathable surface such as vinyl.

So, I can only go along with what your builder suggests. Seal with Unibond PVA and try again with a different product.

[TonyV]

Screwfix sell self levelling compound that will do 5 to 50 mm

[TonyV]

This is product
http://www.screwfix.com/p/no-nonsense-pro-50-levelling-compound-grey-15kg/30074

[Kathyan]

We had the vinyl taken up and the builder came back to remove the floor. It had only crumbled in patches. The rest of the floor was solid! We left it for over a week before having the vinyl re-laid and I'm hoping the problem has been solved!