Are self levelling compounds REALLY that easy?

[AdamW]

My bathroom has a concrete floor. I knocked two small rooms into one to create this bathroom. I am about to start laying the floor, bathroom-rated laminate (yes, was quite expensive, hope it stands up to it!).

Anyway, I have realised that the concrete floor isn't perfectly flat. Nothing more than 3 or 4 mm at any point, but I don't want to lay the floor and find it is a bit wibbly wobbly. So, I was thinking "self-levelling compound, my hero!". Yes, the toilet etc. is bolted to the floor but the shape of it is such that even with 4mm of compound around the bottom, it will lift out.

I have heard conflicting reports. Some say that you just trowel it out very roughly, leave it for a day and it slops about by itself and forms a perfectly flat (well, as flat as the Earth!) floor through gravity. Others say that you trowel it out, and all the self-levelling does is get rid of trowel marks, not level itself. Which is it?

Are there any particular brands which are really good compared with others? I am rubbish at plastering so if it requires any level of skill I'm screwed.

Also, do I need to erect batons around the floor to stop the compound oozing out everywhere? I don't need to feather edge at the door as the next room is carpet therefore there will be a considerable difference in height already (laminate is VERY thick)

 

[DAZB]

For a minor difference like 3-4mm you would be better to just use the decent green tile style of laminate floor underlay.This stuff is about 10mm thick and will enable you to lose any minor imperfections with your floor. The only down side to this is that it will raise your floor even more. If that isn't practical then laying the self levelling compound is fairly straight forward. As long as you have it mixed correctly it is poured onto the floor and lightly spread around with a float and it will then level itself off and fill up any low spots. You won't normally have to lay batons to contain it because it shouldn't be mixed so it's like water but more like the consistency of custard and custard won't flow very fast. Hope this helps.

 

[AdamW]

Cheers Daz. Unfortunately the felt-style underlay can't be used under this particular laminate in a bathroom (although surely the floor is meant to be waterproof anyway ) so I have to use that stuff like that thin expanded plastic that electrical goods come wrapped in. This stuff is incredibly thin and doesn't really take up any imperfections at all, so you need a very flat floor.

Consistency of custard, that sounds more like it. I might lay batons to be on the safe side, plus it will make a neater edge, but it sounds like even my hamfisted skills with a trowel might be adequate

 

[2scoops0406]

I've used levelling compund once. The stuff I used was a powder, which had to be mixed with water (fairly obviously!) The only tip I would give is if you use the powder stuff, ensure that you give the bucket you mix it in a few good taps on the side in order to get rid of any air bubbles. Good luck, it's a lot easier than plastering !!

 

[ohmygodwhathaveyoudone]

adam,i've just laid aqua-loc laminate in my kitchen/hall/toilet but used a 3mm foam underlay which levels off big varients in height 2-4mm & the joints are still watertight.you can get the cushion underlay from b&q.hope this helps.

 

[AdamW]

I've used levelling compund once. The stuff I used was a powder, which had to be mixed with water (fairly obviously!) The only tip I would give is if you use the powder stuff, ensure that you give the bucket you mix it in a few good taps on the side in order to get rid of any air bubbles. Good luck, it's a lot easier than plastering !!

Were you happy with the results?

 

[shaggy]

My advice if you use self-levelling is to seal the concrete with pva first to reduce the suction. The first time I used it I really believed it self-levelled, but I was left with ripples because the floor sucked the water out too quickly. It does work better as a thicker layer but as DAZ says you do have to float it as level as possible.

 

[2scoops0406]

Yeah, it was fine even after 5 years. Pretty easy really, and one of the first DIY jobs I ever undertook. Shouldn't cause you too much grief, I would hazzard.

 

[AdamW]

I was thinking about PVA to seal it, will definitely use it now.

PVA, is there anything it can't do?

 

[2scoops0406]

You can even chew it, it's the main ingredient of chewing gum!

 

[AdamW]

You can even chew it, it's the main ingredient of chewing gum!

Are you serious?!

 

[2scoops0406]

You can even chew it, it's the main ingredient of chewing gum!

Are you serious?!

Yes!