kitchen floor prep

[negsy26]

hi guys, would love some advice on a kitchen floor.said floor is 30msq and half of it has floor boards down the other half is concrete! ceramic tiles are going down probably 300mmx300mmx10mm. devimat going down too. customer wants it done right but with minimum floor raise as possible.existing wooden floor is in good condition and fairly stable.i was going to screw down existing floor to really make sure of no movement then put down 6mm backerboard over the whole area using spf ( dont fancy screwing through the concrete !) devimat on top the backerboard then spf & tile, grout with flexi. what do you think?

 

[doug boardley]

youll need an expansion joint between the two substrates negsy, I'd also be using a de-coupling mat,(dtra, dural ci) especially as you're having a devimat

 

[grumpygrouter]

You will probably also need to plug and screw the hardiebacker down as it isn't exactly flat. The adhesive isn't strong enought to pull it down and keep it down in my experience.

As per Doug you will need and expansion joint as well.

 

[negsy26]

so somthing like ditra matting down first then the backerboard or just the matting?

 

[david campbell]

if the existing wood floor is ply,then the ditra should be fine just make sure you split it where the expansion should be

 

[negsy26]

the existing wooden floor is the old type 'planks' not even tongue & groove so i guess ditra matting is a no go then?

 

[doug boardley]

I'd be taking the planks out and replace with 25mm wbp plywood, seriously:yikes:

 

[negsy26]

i think im going to do this - fix down existing ' planks ' securely,then, 10mm backerboard fixed down with ardex 7001 (and screwed on wooden part of exsisting ) then the devimat then latex over with arditex na, finally a spf to fix the tiles with and a flexi grout !! i think that should do it !! what ya reckon ?!!

 

[DHTiling]

Is the break between the 2 substrates in a straight line..?

 

[doug boardley]

are you not going to bother with a dural/ ditra uncoupling membrane?

 

[negsy26]

yes dave the break between the 2 substrates is in a straight line, do you really think i need a membrane after all the other stuff doug ?!

 

[DHTiling]

Use a movement joint betwen the 2 substrates and NO membrane needed..