Leveling a timber floor and concrete floor

8 Dec 2016
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United Kingdom
Hello this is my first post.

I'm currently renovating a house and its the first time I have taken on many of the tasks. I'm supposed I've not posted sooner.


I have knocked through two walls to create a large kitchen diner which has all gone well.

However 2/3 of the room are on a concrete floor which requires leveling using compound.

1/3 was chipboard over suspended floor above a large crawl space. The chipboard has rotten and been removed and will be replaced with marine ply.


shall I level the concrete floor then shim up the plywood when I fit it to be level with the concrete floor or lay the plywood at its existing level and then lay self leveling compound over the whole floor using a flexible self leveling compound such as Stopgap 700.

All information provided is greatly appreciated.


Oh and I should have mentioned desired final floor covering is laminate flooring.
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Get plywood as level with concrete as you can then prime and screed. Best way.
you have an opportunity to insulate the timber floor between the joists, also get all your plumbing and services down - electrics, network speaker cable etc. Lastly the thickness of the timber floor is dependant on the spacing of the joists. How have you worked out what thickness ply to use? Have you considered t&g floorboards - lots cheaper than marine ply, which you don't need inside a house
Thanks dazlight I was hoping to get away with it really but I will take your advice. I'm taking it the same primer can be used on both services.

It was 18mm chipboard that had rotted so replaced it with 18mm marine ply to prevent the same thing happening again. All services are in and its insulated already. There is pretty good access beneath if I decide to fit anything in the future. Thanks for the advice
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How long has the screed been down ?
It might need a moisture test.
Have you took the bricks out the floor from old walls and made good the dpm ?
All important for the future mate.
On primer use P131 an neat on ply and diluted on concrete
The screed has been down since 1979 I suppose. All the bricks have been removed so its just a bare concrete now. Not really following with the dpm though. Isn't the dpm under the concrete floor? How can I perform a moisture test?

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