Expansion between dissimilar wood types in outbuilding

[FunkyJive]

I've asked a similar question in the flooring section but no reply to-date, so please forgive me for trying here but I shortly need to order materials.

I have a wooden outbuilding with tanelised 22mm T&G wooden floor, fixed to tanelised bearers over concrete. It will contain audio recording equipment so the floor must be really solid to minimise noise and potential for creaking.

I'm minded to lay 1800 x 600 x 18mm spruce ply boards over the T&G for the flooring, sandwiching a 5mm moisture/thermal barrier material between.

So, with the T&G timbers exposed to the outside air, and the ply board above the insulating membrane, should I worry about dissimilar expansion/contraction and leave the ply to 'float' above the existing T&G floor (least-preferred option), or can I lock the ply sheets down with copious screws for improved solidity and reduced potential for conducted noise through the floor?

Thanks in advance.

FJ

 

[big-all]

simple answer wood will expand about 0.005% in its length but up to 15 % across the grain in other word 1mm on a 1220x2440 ply board because its cross ply its only the 5mm at the edge that can expand by up to 10% so 1mm max

screw to your hearts content [every 6"]

 

[foxhole]

You can't beat a good screw.

 

[big-all]

You can't beat a good screw.

ooerr misses
i have forgotten what one off those is

 

[FunkyJive]

Big thanks, Big-All.

A day screwing to my hearts content sounds good to me


All the best,

FJ