On Sun, 27 Feb 2005 22:22:16 +0000, Mary Fisher wrote:


"Tim S" wrote in message
news


Does wood expand when it gets hot ?

It seems to me that in my house wood expands when it's cold & wet and
shrinks when it's hot & dry.

There are two different effects here. Wood tends to swell when wet, but it
will also expand due to temperature by a very similar amount to steel,
all other effects remaining constant. That might very well be offset by
the drying out shrinkage.

Then again, there's not much "wood" involve in laminate. So the question
is whether an MDF like substrate will expand when damp? That I don't know.

I've been to a village hall where no expansion was allowed for the laminate
flooring. there was a huge hump in the middle of the floor and no chairs or
tables were stable in that part.

A son was asked to remove laminate flooring from a kitchen where it had been
laid with no gap. It wasn't a huge area but there were humps.

The reasons aren't worth arguing about, expansion gaps are essential if the
floor is to remain flat.

Absolutely agree Mary. Better to have too much gap rather than too little.

However the question was whether 10mm should be blindly applied in every
case. The answer is, 10mm is safe in all reasonable circumstances, but can
I believe be reduced quite safely for smaller rooms.

I laid laminate in the hall of my former flat in London, which was long
and thin and offset. I cut the gaps down to 3-5mm along the sides opposing
the shorter dimension (about 1.2m) as 10mm was not necessary, but more
importantly, it was rather useful to do so around the fiddly bits like
multiple adjoining door frames where a larger gap would look obvious and
unsightly.

Certainly survived a cycle through one of the hottest summers seen down
south. Biggest problem I had was the cr*p state of the subfloor - great
build quality, these 1980's flats!

Tim