Expansion gap in hot weather

[toomuchworknotenoughtime]

I'm not really getting this expansion gap business!!

I have 4 x 4m room in which to lay solid oak 20mm thick 125mm wide boards (2.2-3.6m lengths). T&G along lengths only.

I've got them acclimatising in the bedroom upstairs.

It's hot. Does that that mean they will expand because they will be able to absorb and hold more moisture. Or does it mean they will contract because moisture will be evaporated. (I think the former).

Question is, if the former, and the boards are at maximum expansion, what happens if I float them with a 15mm gap all round. As the weather cools and they contract there's no way the skirting will cover them. How do I account for the weather in working out the expansion gap?

 

[WoodYouLike]

in a room 4 by 4 and solid oak floorboards your gap has to be at least 15mm all around (don't forget under doorposts and around fireplaces).

As for seasonal influences during installation: in Winter, during the heating seasons and the lower air humidity in general you should leave wider expansion gaps, in your case around 18 - 20mm so the floor, when the humidity gets higher has room "to move" to.

In summer when no central heating is on and the air humidity is normal or high you should leave the minimum expansion gap needed for your room, in this case around 15 - 16mm.

For solid floor boards we always recommend to use 20 - 22mm thick skirtingboards or 24mm wide flat beading (in front of your skirting boards, flat onto the wood floor)