i am tiling my bathroom floor. what plywood? what adhesive to put on underfloor heating?

Hello Margaret. Normally i would rip up the existing floor boards and lay 18mm WBP plywood. then work from there. because the finish tile would be the same height as the carpet meeting the tiles at the door threshold. If you are overlaying onto existing floorboards. Screw your boards down, then you could overlay 9mm WBP ply then your underfloor heating cable. Adhesive! on timber floors I always use BAL fastflex. It's a rubberiod adhesive which has more flexibilty than any other adhesive on the market. Then a flexible grout ie, Bal Superflex. If you lay a filler/skim coat over the underfloor heating cable first. you will make the laying so much easier and you will promote even warming of the floor. Do not turn the floor heating on untill 2 days after you've grouted, otherwise your grout could srink and crack. You can find me via the web if you need more imfo. Good luck. Regards, Peter

Hi yes the ply does have to be wpb recomendation,s to screwing do differ but i always screw every 200mm then prime with SBR Bal bond not pva,yes you can tile over the underfloor heating using a flexable adhesive,i would recommend Bal,Mapie or Weber.

if you do not know the answer to these questions i would advise against you carrying out the works ,tile adhesive ,tiles grour flexi matting ect can all be expensive materials ,so why chance bodging it up

I have to agree with substructure,this is not a job for you to be doing yourself,Put your money to proper use & pay a pfofessional.

Agree with all points above but would consider putting insulating boards under the matting as May lose a good proportion of the heat through heat conduction from the matting to the substrate below the matting which isn’t what you want ideally.