Dumb question re: nailed & expansion gap on wood floor

[Chri5]

So I understand why a floating floor need expansion.

But a real wood nailed down floor ? Surely the nails prevent all but the most minor movement, the end boards (nearest the walls on two sides being the only board that won't have restiction (via nail fix) on them.

So why do the rules of 15mm all round expansion apply to a real wood fixed floor situation. Same with direct glued, why have an expansion gap if the whole idea of the glue is to fix the board completely to a sub floor.

I'm interested in the science and logic, help

 

[WoodYouLike]

So I understand why a floating floor need expansion.

I'm interested in the science and logic, help

Simple science: wood expands when the wood absorbs more moist from the air - that's nature for you, wood is hygroscopic.
No matter which installation method you use, wood expands when it absorbs more moist than it had when it was first installed. Nails will not stop this, fully bonding the boards will not stop this.

Hence expansion gaps all around the perimeter of a wood floor no matter which installation method is used. Ignore this rule at your own peril

Rule of thumb for solid Oak wood floors: expansion gap = 4 mm per meter width of the room with a minimum of 10mm gap. Room of 4 meter wide means gap (empty gap, DO NOT FILL WITH CORK!) of at least 16mm wide.
(And don't forget gaps around fireplaces, stairs, doorways, cooking islands etc etc etc)

 

[WoodYouLike]

PS Dumb questions don't exist '-)
It's much dumber not to ask if you question some methods

 

[Chri5]

Thanks for your knowledge


I'll stick within all the rules. I do find it odd that a nail is used to permanently secure something, you can even get secret flooring screws to do the same job.

But be virtue of the qualities of the wood and it's environment it still has to breath for the temp and moisture changes with the seasons.

So when is a nail, a screw or a glued base system not a permanent fixing-when it's on a floor

 

[WoodYouLike]

A door is fixed to its hinges, not? When first installed it fits perfectly - well, good quality door and good quality fitter.

Winter? Summer? Spring? Seasonal changes occur in everything wood.
Never heard a wooden furniture piece make noise? Especially when you turn op the heating in a cold room?

That's a product of nature for you