6mm Plywood as subfloor on concrete floor

10 Jan 2013
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United Kingdom
I am seeking some advice on a plywood subfloor on concrete floor.
I have removed tiles on kitchen concrete floor and some screed has come up in patches but the holes are not too big or deep a few mm. I want to put down vinyl floor and was wondering if I could lay 6mm ply down first to level the floor?

Does anyone have any advice on this approach? Will I have problems further down the line. I have read some posts but cannot find a definitive answer about laying 6mm ply on concrete floor.

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Nope - don't do it!!!!!!!!!

the proper solution is to have the whole floor screeded

if you are not prepared to do this/pay for this then you may (MAY) have some success with filling in with self levelling.

be aware that ANY imperfections WILL stick out like a sore thumb under vinyl as very obvious "lumps and bumps"
Thanks for your reply lymmranger

Would I need to self level the whole floor or just the holes?

well I am sticking to my original response!

done correctly a "full" screed will fix all, up here in the "north" you should pay a pro 15-25 per square metre. Be aware that if the room is small there may/will be a minimum charge. If the floor is really bad a second visit may be required. You should get some quotes you may be pleasantly surprised.

IF cash is really tight and it is only a few patches then if you have the skills you ought to be able to fill in. BUT the fact that some screed has lifted usually means that the whole floor is suspect.

This whole process is nothing to do with getting a spirit level perfectly flat floor, it is about a smooth blemish free floor. With sheet vinyl even very small imperfections show through VERY noticeably.

at the end of the day its your house, Oh and your partners grief which will forever "haunt" you!!!!!!!!!!!!
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I am preparing the floor for levelling using Wickes compound and have removed a messy concrete slab in the doorway.

Under the slab is blockwork with plastic dpc either side then the two rooms concrete floors. The wall dpc is visible around the room at ground level but there is none in the doorway.

My concern is - would the dpc in the doorway be at a lower level or has it been removed? If it has been removed and I pour in compond would I form a bridge? If so, how would I reinstate the dpc.


your original post suggested that cash is tight. My response gave you a quick simple and cheap option.

Now you seem hell bent on finding more problems (which will equal more cash!)

either stop it immediately or get a pro in for advice ;)
Hi lymmranger

I didn't say cash was tight I thought 6mm would was a solution you said it wasn't... I have gone for levelling the whole floor with compound for speed as I don't have a kitchen.
The last post I said I was concerned that I might form a bridge with slc because it would appear the dpc is not present across the doorway.

Using the conventional dpc is not an option so was looking for another solution of reinstating dpc

there are "liquid" DPC`s you can use....(before screeding)

but as I said either do a "quick fix" as suggested OR get a PRO in.

the reason for this is that they will (I hope) know what they are doing. they can/will advise you having actually "looked" at your floor. We can only advise based on information you have supplied.

9 times out of 10 all that is required is a screed. This should really be a latex screed rather than self levelling (which doesn't really self level anyway) DIY store self levelling is only really good for minor blemish repairs

If you do want a perfect result then at least get someone in to quote you (and ask questions) Once you know what they advise then do come back for a second opinion

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