Advice for bathroom floor and fitting shower Tray

[marc1977]

Hi,

Im fitting a new bathroom and am after some advice. As you can see in the pictures the current floor is a mixture of 18mm chipboard and OSB board. Im installing underfloor heating and then tiles on top. What should I put on the floor as ive read lots of conflicting advice? Does it need additional plywood or some kind of cement board on top OR can i just put some 6mm insulation board on top of the existing floor? the current floor isnt bad but the OSB board does flex a bit if you apply a lot of pressure.

Second question is about the shower tray - the instructions say that needs to sit on sand and cement mix on top of ply but it seems common to just use building adhesive instead these days?

Thanks

Marc

 

[townfanjon]

OSB is garbage stuff and shouldn't be used in bathrooms .
Use floorboards or flooring grade chipboard with 6 mm tile backer boards .
Shower tray is best on flexible tile adhesive , assuming the tray manufacturer is happy with it , most are.

 

[marc1977]

OSB is garbage stuff and shouldn't be used in bathrooms .
Use floorboards or flooring grade chipboard with 6 mm tile backer boards .
Shower tray is best on flexible tile adhesive , assuming the tray manufacturer is happy with it , most are.

Thanks Jon,

That makes sense. Ill replace the OSB and and some of the damaged chipboard with new chipboard. The tray manufacturer says cement and sand but Im not too worried about the guarantee - so just bed the whole tray on a thick layer of flexible tile adhesive right?

 

[king of pipes]

I would take it all up and replace it with no more ply securely screwed down sbr the board when dry, fix 6mm insulation boards wedi or similar with flexible tile adhesive and screwed down at 300mm centres sbr the insulation boards before laying the heat mat Carrying out all electrical tests before then covering the mat in SLC this surface one dry can be sbr 'd again before tiling on . Kop

 

[marc1977]

I would take it all up and replace it with no more ply securely screwed down sbr the board when dry, fix 6mm insulation boards wedi or similar with flexible tile adhesive and screwed down at 300mm centres sbr the insulation boards before laying the heat mat Carrying out all electrical tests before then covering the mat in SLC this surface one dry can be sbr 'd again before tiling on . Kop

Sorry to many acronyms! what does SBR and SLC mean? ?

 

[king of pipes]

Sorry SBR is a primer sealer , SLC is self leveling compound