DIY bathroom - leveling floor

[Magpie]

Has anyone used floor leveling compound to level a floor? In my SSish way, I am tackling renovating my own bathroom with minimum skills and tools. Half of the floor is existing concrete, the other half has been replaced with timber joists and plywood, leaving a difference of up to 30mm in level, the concrete side being lower.
Would the self leveling compound be the way to go? Is it easy to use? How do you make sure you don't add to much, so it doesn't spill over onto the higher level?

[Marc]

I think it's asking a bit much to use it to raise the level by 30mm. I would either screed it with sand/cement, or lay timber boards on top of the concrete.

[Green Aura]

I agree with marc. I'd frame the lower part with 30mm battens then tongue and groove the entire thing - or walking boards, whichever. Just make sure you waterproof them well.

[doofaloofa]

I agree with GA, and Marc. Consider insulating between the timber, especially if the floor is cold

Is the concrete part dry or damp?

[Magpie]

Trouble is, it's a sloping floor, so ranging from 0mm down to the 30mm, which is why I thought the self leveling stuff. The timber part has been leveled to the highest point of the existing concrete.

[doofaloofa]

AFAIK self levelling compound is for discrepancies of mm's. read the instructions for use to confirm this

To allow for the slope plane or rip down your laths to the appropriate thickness

If you decide to bring up level with a screed of concrete i would remove the higher parts of the concrete floor first, to allow for a decent fill of material. at least 10mm depth if you use a sand based screed, more if you use gravel. The size of the stones will guide your depth needed

How large an area are we talking about?

[Magpie]

It's about 3.6 x 1.2m. Have been to the hardware shop, where the assistant rang the supplier for me. Do-able, in layers, apparently, so I'm giving it a go next week. Using sand as extender for the first fill.
I'm still a little concerned about over-filling, can imagine having to re-do the whole floor to level it again!

[Green Aura]

My understanding is that this self levelling stuff is quite soft (can't think of a proper word there - not hard-wearing I suppose) so even in layers it might not be robust enough for the deeper end. I may, of course, be wholly wrong about that.

But make sure it's suitable for purpose - can it hold up a full bath? Or a lot of foot traffic? You presumably know what it's needed for. If memory serves it's not that cheap, although it might not be so bad if it's a fairly small area.

[Magpie]

I had to do a bit of normal concreting yesterday, and realised how easy it is! So did a layer over part ofthe floor, leaving up to about 10mm for the self leveling to finish. It really isn't cheap - easy-mix is about $10 a 25kg bag, the self-leveling is $65 for a 20kg bag....

[Green Aura]

That sounds like a much better plan. Glad you've sorted it.

[doofaloofa]

The problem you may run into with using concrete without removing some old floor where it meats the wooden floor is cracking and crumbling as the layer of new concrete gets thinner and thinner

[Magpie]

Yes, I didn't make it too thin, as I can level it out with the compound.