Having spent a day stuffing foam into the gaps between some floorboards I wonder why did they always lay the floorboards with bloody great gaps?
If it has something to do with having space to expand then would taking the boards up and re-laying to close the gaps cause problems with movement?
Oh come on they're not "bloody big gaps" 1/8" if that and if they are covered over with carpet or flooring does it realy matter?
They don't (usually). Boards are laid tight but shrink as the property dries out.
Other way round -- because they shrink after laying.
You either need a small gap, or T&G to interlock. Otherwise, if you butt boards together, they'll creek as the edges rub when you walk across the floor. Been there, done that. Also, when the wood is fully seasoned, it will expand and contract a little across the grain, but with enormous force. If it can't expand easily, nasty things will happen, but the bloody great gaps you refer to will have been seasoning shrinkage -- the change in size of seasoned timber over the normal range of humidities is much less than that.
Are you sure the gaps are not caused by shrinkage over time?
If you are talking about T&G flooring - then they don't (or they shouldn't).
The boards should be cramped together tightly (using various methods [1]) so that there is a slight upwards bow in the the boards and then nailed down - The problem that you are experiencing is purely shrinkage.
If the house is a number of years old and the rooms have a fairly constant humidity, then it's possible to strip and relay the boards (putting in extra boards as needed) and it is unlikely that they will continue to shrink (new boards excepted) - but to permanently stop creaking is another matter.
The question is: is it really worth doing all that work just to tighten up the joints - along with removing and refixing the skirting?
[1] Patent flooring cramps, timber battens nailed to the joists and folding wedges placed between the batten and boards and then 'hammered' to gether to cramp the boards etc.BRG
Thank you everyone. I feel a bit silly that shrinkage never occurred to me.
I reckon 1% across the grain summer to CH heated winter..so 3mm would be about right for a 300mm plank - say 12" wide.
Differential movement may cause you to need a little more than that.
.
Two things.
You should GLUE teh floor T & G together to eliminate gaps, but then it needs to 'float' as te expansion then ahppens on te deges.
Old boards were probably laid, and stayed, in quite high humidity. Modern central heating lowers RH way below what old houses ever experienced.
So massive winter shrinkage (indoors) can result.
On outside timber, the RH trends to be higher winter than summer, so you get doors sticking in winter.,.odd aint it?
It's reckoned that softwood shrinks by 0.25% for every 1% drop in moisture content. As it normally starts at 17%, and often ends up around
5% in dry conditions, 150mm boards should shrink by about 4mm. Mine show no signs of expanding again, but I doubt the humidity in the house ever gets high enough
I did that to cover a fireplace cement base just before I got my F/boards sanded /coated and I doubt they had ever been lifted before to any great degree and I can tell you .It was a LOT of work and very messy in a Victorian flat
Stuart .
That seems high to me..but then I normally think hardwood..
That is also only across the grain. And then not across 'quarter' grain. That's less than tangential cut boards.
Which is why logs split with radial cracks when cut down.
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