Shuttering ply

ardinn

Hi

Complete dope here putting down a floor so bear with me.

Im using shuttering ply, and intend to scorch and varnish/harden it, the issue is the room is about as square as a hexagon, and the ply I have bought is warped to bits.

My question is will ply expand when the room is heated like other wood, there are a few gaps at the top of the room, and im slowly working them out on the way down, but im wondering will these close a small bit as the temp increases.

The job doesnt need to be perfect, just passable. So not a big issue its just bugging the life out of me!

listermint

You should leave 12 to 15mm around all edges of the room. This would be under the skirting , for expansion

the_pen_turner

Ply wont really expand that much . Probably not a noticable amount
More likely to shrink with the heat

Lumen

I think that expansion in wood is mainly from changes in moisture rather than temperature.

Plywood is quite resistant to lateral expansion as it's cross-laminated, so the layers are working against each other, and so expands only a little more than solid timber does along the grain, which is very, very small (whereas wood expands a great deal across the grain, think of it like a bundle of straws swelling).

So basically if you're putting it down indoors and have given it some time to adjust to the temperature and humidity, it's unlikely to expand very much, firstly because plywood is quite stable, and secondly because your room is a fairly constant environment.

Outdoors is a different matter, obvs.

listermint

On the contrary cheap shuttering ply can expand and contract significantly to cause buckling.

Better to take precautions than lay it too tight. More expensive plywoods have better stability though.

GreeBo

listermint wrote: »

On the contrary cheap shuttering ply can expand and contract significantly to cause buckling.

Better to take precautions than lay it too tight. More expensive plywoods have better stability though.

Doesnt that usually expand and contract in thickness rather than length/width though?

The Continental Op

GreeBo wrote: »

Doesnt that usually expand and contract in thickness rather than length/width though?

If you have it exposed and nailed down outside (not that you should) you can see that it warps through expansion when it gets wet far more than more expensive grades. But indoors I doubt its a problem.