Recommendation: HELP...Priming before floor leveling compound???

[Stu2010]

Hi Guys

I'm going to be tiling over some under floor heating, the sub floor is Timber with 18mm ply so i was going to use a latex based floor level compound.. I'm doing about 20 sq/m of 60cm X 60cm porcelain tiles.........I have 3 questions I'm afraid!!

1) do i need to prime the ply before adding the floor level compound??? or.. do i prime the leveled floor before tiling...or..no primer at all???

2) If yes to priming the floor.. any recommendations on what primer to use ??

3) any recommendations on what latex floor level compound to use.. as there seams to be a big difference in price ?

Thanks a lot guys

Stu

[whitebeam]

Is this wired UFH on the ply.

[Brinkley]

hi stu i would use mapei fibre plan and yes definitely you need to prime with the correct primer with fibre plan i use mapei eco prim

[doug boardley]

you need to certainly prime the back and edges of the ply whatever latex you use. Some levelling compounds require that the face side is not primed tho. Have you thought about overlaying the ply with some 6mm insulation board?