Oak floor query

[AlvoSlim]

Hi all.

We've done a garage conversion. Concrete garage floor has had a waterproof membrane laid, a load of joists with insulation between, then 22mm chipboard floorboards on top.

I fancy solid oak floor, but I'm picking up mixed messages and am confused!

1) I'm told that I can lay solid oak directly onto the chipboard and nail it down.
2) I'm told to leave 10mm expansion gaps around the edge.

If it's nailed down, how can it expand that much? If it's going to want to expand that much, should it really be nailed down?

I'm looking at a 18mm oak floor if that makes any difference. Help gratefully received as ever. Ta.

 

[AronSearle]

You can nail to chipboard, but it's not the best way to do it by far, as it has weak holding power, you should have laid some plywood (never cheap chinese ****).

When you nail the boards, you want to leave a card spaced gap between each board for expansion (you don't cramp dry boards, cramping them tight is only for wettish softwood T&G).

The expansion around the permiter is to protect the building with nailed flooring. The expansion and shrinkage happens between the boards, you are correct that if they are nailed the whole floor can't move, maybe several boards in a 'group' can. But on the odd chance the boards excessivly expand, they can buckle up, or they can expand outwards, if the latter happens they can push out your walls.

Floating floors are different, and the perimiter gap has more of a function.