Hole size for 15mm speedfit

[pjo123]

Probably my stupidest question yet

Running a length of 15mm speedfit through my floor joists. Does it expand or can I simply use say a 16mm drill for the holes please?

Thanks

 

[Elkato531]

I'd go slightly larger. It makes threading the pipe through the holes easier and means its less likely to creak when the pipe expands and contracts.

 

[TicklyT]

16mm is a bit too tight unless you can guarantee perfect alignment of every hole, as scratching the pipe during installation can lead to leaks.

If the pipe binds in the holes it can cause all sorts of creaking noises with thermal expansion.

I would go for about 20mm, maybe even 25mm and a piece of hair felt lining in the holes to stop creaks

 

[dreadnoughtheating]

Using a mains powered 'right-angled' drill I drill a 22mm hole, line it with a short section of 21.5mm overflow tube, so that (as quoted above) the outer of the fluid carrying pipe does not chaff on the timber.

Overkill?, I like to sleep at night.

DH