plying - TilersForums.co.uk | Tile Forums

andyb_987 · 23-02-2008

Is it ok to use standard ply when plying out a bathroom floor as long as it is primed?

When i say standard I mean not exterior ply.

Cheers

GatesheadCol · 23-02-2008

Hi Andy.

The ply must be exterior grade ideally 18mm but you cvan get away with 12 mm if your worried about the level being raised too much.

If level is a concern use Hardie cement based backer boards 6mm for floors available from Topps tiles.

Ther reason you must use exterior grade is for water. If you do not use exterior grade the ply can get water ingressed and can end up expanding like a weetebix.

I'm sure DH will be able to provide a very technical answer on the properties of Exterior grade ply versus normal as he is the top man for stuff like that.

Hope this helps you.

Col

davy_G · 23-02-2008

Yep, Always use exterior grade and in wetrooms or mosaic floors i use marine ply

**grumpygrouter** · 23-02-2008

Exterior grade ply is more moisture stable than interior grade, the resins are designed to be moisture resistant. Marine ply being the best (I believe) and most expensive. Normally WBP grade ply is fine for tiling purposes.

Grumpy

Keith · 23-02-2008

Hi all . Would like to know a couple of things about plying.using exterior or marine 12 or 15mm ply on a wooden floor. Should one A Use an adhesive to stick the ply down then screw it or B Prime the underside of the ply ,lay it and screw it down or C Just lay the ply down and screw it then prime it. Would like to know which you choose. Cheers. I have a 16sq mt bathroom floor to lay.

davy_G · 23-02-2008

Bathroom floor, possibly use marine and the thickness is dependant on amount of movement you are trying to minimise if any.
I would screw the ply down at 200mm centres with chipboard screws no longer than the thickness of the ply added to the thickness of the exsisting wooden floor. Remember you will screw the odd screw a few mm beneath the ply surface.
Then prime surface to tile as normal.
So that is option C for me.

Keith · 23-02-2008

Thanks for that Dave. I'll go for option C . This forum is the best.

andyb_987 · 23-02-2008

thanks guys!