Is tile underlay necessary ....

[tgbrooks]

Hi,

I have just installed wet area plywood (19 mm) flooring for the bathroom renovation. Because of the odd size and shape of the room I have not utilized the tongue and groove to join ply sheets, but have used double joists and "noggins" between joists to support all edges of the ply sheets.

Therefore I expect very little movement on the floor, but is is still necessary to use ceramic tile underlay as well ?. Does the CTU perform a role other than bridging (unsupported) joins on sheet flooring ?


Trevor

[silentC]

It gives the tile adhesive something better to stick to. But since this is a bathroom, you will be waterproofing the floor anyway, so the glue has to stick to the membrane, not the particle board. But then, how well will the membrane stick to the floor? Plenty of houses have particle board floors in wet areas, so I suppose it must be OK. I put compressed fibro sheet in all my wet areas.