Un-levelling compound

[Andy Burns]

OK, I know the usual self-levelling compound isn't really self-levelling. I have a porch floor that I need to raise the level by

30mm to meet a cill level at the front and 40mm at the back to meet the hall floor level, so I want a shallow incline rather than actually level (there used to be an internal door and cill where the difference in levels occurs).

I'm thinking of Wickes Deep Base Levelling compound which it says is OK for between 5 and 50mm. The instructions suggest mixing it slightly drier the thicker the layer you're pouring, which would presumably make it more 'positionable'?

I need to 'lose' 10mm over 1.8m, will it co-operate, or will it do what I *don't* want, and level itself anyway? Better to fill it in a couple of layers, loosing 5mm on each instead?

Originally I was thinking of a sand/cement screen but 30mm seems a bit thin and would risk breaking up

Thoughts?

[The Natural Philosopher]

because I actually had a lot I used quick setting ardurit tile cement to do similar.

if you build a frame to run a board over you can scrape it to a rough level and float the rest out.

Then use a smoothing compound on top for a perfect finish or tile or or carpet it.

It sets fast enough not to slump and you can mix it very 'stiff' anyway.

its sorta like car body filler, only goes off in water and has sand rather than mica filler.

Its on my list of 'things that do more than it says on the tin (sack) , actually'

[Tim Watts]

On Thursday 15 August 2013 12:53 Andy Burns wrote in uk.d-i-y:

Are you going to tile this?

If so, it might be easier to lay level and get the tiler to ramp the tile adhesive (in practice they would skim some adhesive over about 1m and form a

10mm ramp into this. You would not ntoice the change in level.

30mm is still a lot for SLC though with filler (eg granite chippings) some can go this thick.

The other option, for 30mm, is to use an SBR modified sand/cement screed.

If you have 2 parallel walls to screw temporary levelling guides to (strips of 1/2 x 1" wood) you could lay this pretty easily.

[Andy Burns]

No, not planning on it.

I've done that myself when tiling the kitchen floor, bridged a bump between original and extension levels, as you say, not noticeable unless you roll a marble over it.

I noticed many of the fillers wouldn't cope with more than 20mm, but the Wickes one said it could, I was going to look at the Mapei ones (is that what you used on the bungalow?)

Yes could manage that, I'll look into that as an option, thanks ...

>

[Tim Watts]

On Thursday 15 August 2013 13:24 Andy Burns wrote in uk.d-i-y:

No - F.Ball Stopgap 300 HD

That goes to 20 -r 25mm with filler IIRC - but nothing stops you laying multiple pours.

It's what I worked from and it worked. Forget Isopol - all SBR is the same.

2 warnings: 1) SBR screed is much more fluid than screed mixed with the same volume of water so you need to mix dryer than you think. 2) The stuff sticks to everything and is a bastard to get off when cured (quite quick) (BTW this is good). Have some white spirit handy and wash your float and tools immediately. You may need to scrub your float with wire wool and spirit.

Oh - and a 3rd:

3) Get the level right - I had a lump and my SDS with a scutch comb chisel barely touched it after a week. Sets like iron.

[Andy Burns]

Thanks, sounds good, will read later ...

[Andy Burns]

I've only got one old bag of tile cement left, but I think it'll be far too old and too small to be any use ...

[stuart noble]

For 30mm indoors with no damp problems I'd use pva. In some ways this is preferable anyway because it combines well with mortar. SBR needs constant stirring to keep it in the mix

[Andy Burns]

In the end, I went with the Wickes deep base SLC. It coped with the depth well, I mixed three of those yellow builders tubs at a time each with two 20kg bags, which poured about 15-20mm at a time, it really does level without any persuasion, hard enough to walk on in just over an hour.

I ended up needing a 2-3mm top-up in places, didn't really expect it to feather very well, but gave it a try anyway and it doesn't, so will finish off with some latex tomorrow.