Levelling really bad floor

[GCarnegi]

I recently took down a block wall between my kitchen and dining rm and now have a good sized room with half good condition (although slightly squeaky) wooden floorboards and half (kitchen half) concrete.

The kitchen must have sloped slightly as the concrete drops the further away from the dining room it goes. Where the concrete joins the floorboards the concrete sits almost 1/4" HIGHER than the wood in some places.

I want to put down Karndean (I'm getting someone in to lay it) and obviously I need to level the floor first.

I've been told to nail 6mm marine ply at 4" centres over the floorboards and to screed the kitchen to the same level.

Obviously this needs to be done BEFORE fitting my new kitchen units and I can't get anyone to do it for me in that time frame - would really need to be done this weekend, so it looks like I'm landed with doing it myself.

I'm wondering what material I should use. The majority of the kitchen will need 1/4" depth but will increase to 1/2" against the back wall.

Room area is about 3.5mx5.5m with the concrete part about 3.5x2.5m.

Thing is that there are 1940's lino tiles glued to the concrete floor which are a nightmare to shift. It took me half an hour to get one of them up - and even then much of the bitumen type glue remained on the floor. I was hoping that if they're stuck that well, then can I just screed over them - using what material?

The concrete floor is a 6" reinforced slab with crawling space underneath so damp isn't a problem.

Should I glue ply down under where the units would be (against two adjoining walls) or screed the whole lot?

I obviously want the floor to look good and I don't want to see a line under the Karndean where the concrete and ply meet.

any help is much appreciated.
thanks
Guy

 

[mattysupra]

follow instructions at top of forum how to level a very uneven wooden subfloor But only plywood the wooden side. Step the plywood up in thickness or over ply the area where the floor gets deeper. You need to mix a bit of compound and ramp the joints so no sharp edges or steps between different levels of plywood. Now lay levelling compound over whole floor ( plywood and concrete) I would take up the tiles tho. They are hard work without very sharp heavy scrapper. With good scraper it takes me about 20 mins to strip up 20 sq meters. If they really wont budge you can go over the top with primer (131) not diluted Also read the sticky on how to use levelling compound.
Tip- dont do part mixes. also mix to much. If dont keep above 3mm depth you will be in trouble trying to level.

 

[GCarnegi]

I hired a rotary breaker with a sharp wide chisel and got them up without too much of a problem in the end (lots of sweat and a couple of blisters).

I then checked the level and the floor was around 10-20mm too deep. I heard this was too deep for latex so treated with PVA and then levelled with soft sand/cement 3.5/1 to about 4mm below finished depth.

Will latex the rest.

PS I discovered that rotary breakers and Sunday mornings don't generally go down well with neighbours.

thanks for your help.
Guy