Totally uneven floor to tile

[simonb43]

Hi All, Have a floor to tile using sparkly quartz tiles, not sure of size yet, but floor is a total nightmare. One section is floor boards, which is already higher than the new concrete floor, done by the builder, who has no idea how to put a flat floor down. High spots all over the place. Kitchen already fitted as are skirting boards. Now, i have to board the wooden section with 6mm backer boards, but what is the best option for the wonky concrete floor ? It is as much as 10mm, maybe more, lower than the wooden floor. All advice greatly appreciated as this is a good job for me, but not sure how to sort out the levels, especially with skirting and kickboards already in place. Too much height will leave them so small it will look rubbish. Hope someone can help. Thanks in advance :smilewinkgrin:

 

[White Room]

Could use a self leveling compound to bring up the screed floor but use a control joint between the two different surfaces

 

[hillhead]

10mm plus 6mm plus a little would near add up to 18mm exterior grade ply !!
just a thought and would work out cheaper than levelling compound i think.
I'm not sure if backer board go up to that size?

 

[doug boardley]

What about using an insulation board on the concrete floor to bring it up to timber + Hbb level?

 

[david campbell]

i would also remove the skirtings,they will be getting raised about 15mm with the tiling alone so no need for painting

 

[simonb43]

Was thinking of using backer boards to raise concrete floor to same level as wooden floor. Approx measurements for wooden section is 5m2 and concrete is 16m2. I think self levelling would be more expensive than using boards. Am i right ?