floor level problem, help please

[happyhero]

Hi I know this subject has come up before but none of the previous I could find seemed to cover my problem.



I have a fairly big extension at the back of my house that is as wide as the house, approx. 3.5m x 5m. The whole floor is sloping towards the back garden but we are ok with that as it is not too bad and we hardly notice it.



The floor is that typical 4" square parquet tile effect and is layed on hardboard.



There was a breeze block wall splitting the extension in two until recently so that one side added to our kitchen and gave us a nice long kitchen and the other bigger half gave us a dining room. Well we knocked down the wall so that we can have a massive kitchen-diner with a big country table in it, but doing this has left a 2m plus trench in the floor where the wall is with the parquet flooring each side. Trouble is although the floor is one when it gets near the back door, at the beginning there is well over 1/2" maybe nearly an inch difference either side of the trench (shallow trench by the way).



Now we are laying a new laminate floor thoughout the ground floor which I have started in the hall and was advised by our builder friend to lay on top of the parquet as it all works out the same height of "under stuff" as the 7mm green felt pads I used in the hall. He has advised that we just lay that 3mm cushioning between the laminate and where we have parquet. He said the parquet gives a good base and it would be crazy to remove the large amount we have so its best to lay on top with the 3mm stuff between.



So now if I use a latex leveller to level the two sides of the trench which sounds fine what am I going to do about the fact the whole extension slopes slightly down towards the back, wont the leveller all start running out of the trench towards the back door?



I could take some of the parquet away on the high side and maybe even some of the hardboard underneath and then level but still what about the whole extension sloping towards the back?



I know I cant really use filler but as a way to explain, if I was using filler I could use a long straight edge and fill the trench level until I was happy but with latex leveller (which I have never yet used) doesn't it just do its own thing and find a level?



Sorry for such a long question, but any help or tips please?

 

[barryo]

Half-inch to an inch is too much for self-levelling compound unless you use multi layers and/or some aggregate in it (for which you have to follow manufacturer's instructions and it's a pretty skilled job). Best to lay a dryish mortar screed say 4:1 sand:cement and level off as you describe. Google or search forums for "floor screeding" and you'll get lots of tips.

 

[happyhero]

Yes my builder friend said to put a screed in first which will be a bit thin for a screed so to put plenty of PVA in but when I do the final latexing level I will still have problems with my sloping floor

 

[barryo]

If you take enough care about the screeding you don't need self-levelling.

 

[happyhero]

If you take enough care about the screeding you don't need self-levelling.

cheers barryo your being really helpful. don't mean to go on and on about it but if I made a screed say in one of those plastic paint buckets you can get how much PVA would you put in it roughly ie what ratio, to insure it wont crack bearing in mind the depth. I have measured it now and from bottom of trench to top of parquet is 44mm at worst and 16mm at best, is that still going to be ok for screed not cracking?

 

[barryo]

Normally you want screed to be at least a couple of inches thick. There are a couple of ways to stop cracking if thinner. You can get bags of short fibres to mix into the screed from some builder's merchants. If you have a problem getting hold of these you can use a metal mesh, say chicken wire, or rolls of expanded metal, which acts like reinforcement in concrete. Or you could use corner beads (normally used in plastering). Flatten them out and bed them in the screed as you lay it. Don't make the mix too wet. It should retain its shape in a ball when you squeeze in your hand (not ooze through your fingers).

 

[barryo]

PVA to strengthen the mix is a bit of guesswork. For a 10 litre bucket I'd guess maybe a cupful of PVA but others might have a better idea.

 

[barryo]

Sorry, it's a bit late and I keep realising I've missed things out.

To use the chicken wire/mesh, I'd fasten it down in the 'trench' in a few places with screws/plugs, masonry nails or similar. Wrap part of the mesh round the screws/nails to hold it. Get the whole lot below the top level and make sure you spread the mix well in to get rid of air pockets. Might be worth painting a layer of neat PVA on the screed when it's dry.