Leveling a concrete floor

[Jacko]

I know...I know, there's absolutely tons of posts about this already but having read about 100 (many of them seeming to conflict with each other) I can't find the answer I'll looking for.

I'm sorting out a room in my cellar to fit a toilet. The room used to be a coal bunker and the concrete floor is really uneven.

The room is 6" square and there's a reasonably smooth and level section by the door but the rest of the floor that was behind the original wall seems to have had concrete just tipped behind it. Overall it drops about 20mm from corner to corner. But in between it rises to nothing or has holes about 35 - 40 mm deep. It was much worse than this but I've used a SDS drill to take the worst lumps off.

The ceiling is already low so I don't want to lift the floor any more than I have to, I've put a generous coat of PVA (4 to 1) on the floor to provide a bond and have got a bag of Wickes Self Leveling Compound (but am thinking of taking it back)

What's the best method of getting the floor level enough for the intended use. I was going to use sand and cement with PVA (4 to 1 dilution) but I'm worried about it breaking up and lifting were it would be really thin.

Any help much appreciated

Thanks

Richard

[Robbo]

Given that it's going to be a loo and will incur "Splashback" at times of inebriated poor aiming why not tile it and level it at the same time so to speak. I don't think 6-10mm extra will make a lot of difference in the height.

[Stuart Noble]

It'll be fine. The whole point of these products is that they feather to a fine edge and don't break up.

You need the bit under the wc to be flat *and* level, and the rest of it can be just flat. Use a length of wood to line it up with the doorway

[Jacko]

Thanks for the advice to date.

I don't want to tile, lots of reasons, so I think I'll go with the sand, cement mixed with PVA option - can I take this mix to a feather edge without it breaking up or do i need to allow a specific thickness across the floor

Cheers

Richard

Stuart Noble wrote:

[Stuart Noble]

I've done this with "B&Q general purpose mortar" with 4 water: 1pva. This is much finer than your normal sharp sand mix.

[Jacko]

Wickes do a bricklaying mortar mix in bags for next to nothing is this the sort of stuff I need (with PVA added) or do I need to use other sand

Cheers

Richard

Stuart Noble wrote:

[Stuart Noble]

General purpose mortar is different, but also next to nothing

[Jacko]

Thanks Stuart, what sand is it mixed with just in case its not available when I go - then I can buy seperate bags

Cheers

Richard

Stuart Noble wrote:

[Stuart Noble]

I think it's a blend of different sands and particle sizes. At a push you could probably sieve ordinary sharp sand to get rid of the gritty bits