Expansion Gaps ?

[STEVEROG]

Do I need to leave gaps between individual pieces of plywood that make up my complete plywood floor that I am going to tile onto?

The floor is 18mm thick WBP. It will be glued and screwed down.

What do I do with the gaps? Fill them or leave them clear? If to be filled, what do I fill with?

Thanks,
#
Steve

[david campbell]

how big are the gaps?

[brian c]

should allow 2mm for expansion...ie dont butt up to each other...you could fill with grip fill.

[STEVEROG]

Gaps are as big or small as I want them. I don't have to put any gaps in, I just wondered if I needed to?

I will be glueing the screwing each piece down so I doubt that there should be much movement but I dont really know what the expansion is like for plywood.

Steve

[andy tiler]

hi steverog yes you should leave a gap. i normaly use 3mm spacers for the gap and fill with silicone for the movement.

[STEVEROG]

Right, so I am guessing here (please correct this if its total tosh) but I suppose with small gaps and some silicone in them if the boards do shift a bit they can move towards each other (or away) and in the event that they move toward each other they have less chance of colliding edge to edge which I assume is the big problem to avoid as this could cause them to bulge and pop tiles. I assume that the slight sideways movement is ok as long as the tile adhesive has a bit of give - flexy stuff like the BAL.

Is this right?

Steve

[andy tiler]

sounds ok to me steve