I am planning to install prefinished solid 3 1/4" wide by 3/4" thick ash hardwood in my home using 2" cleats. I live in Canada, so the average indoor humidity difference between winter and summer is quite high, maybe 50%. I don't use air-con in the summer. It is early December now, so I expect each board to expand in width by approximately .01" between now and summer.
Is there any reason why I should not put small gaps of .01" between each board (using a removable shim) as I nail them down? I still plan to leave a 1/2" gap around the entire room, just in case.
I ask this because I don't understand how a tightly-fitted floor is supposed to expand at all. What happens to the nails around the periphery if the whole floor moves by a good fraction of an inch? Are they simply ripped or bent out of place? By 1/2 an inch?? Or does the 45 degree angle of the nails force each board (and progressively the whole floor) to rise up by the same amount as the expansion? And when they shrink back down what pulls them back into place? People walking on the floor?
In removing my old maple floors I saw no such evidence of major movement. So I ask, quite literally, what gives?