holes for plastic pipe through joists

[XanderHarris]

Hi, what size holes would people suggest drilling when installing 22mm and 15mm plastic pipe through joist to allow for expansion.

 

[denso13]

25 and 20mm positioned as per http://www.trada.co.uk/faq/viewAnswer/28F42B4A-B9EE-4ADB-B22D-8C11EC1434D0

 

[CBF]

I use 20mm for 15mm & 25mm for 22mm, but do a search (or someone might have a link) because there are distances for drilling a joist

 

[XanderHarris]

Is 25mm not abit tight for 22mm plastic pipes? They will be heating pipes so will expand.

 

[denso13]

Is 25mm not abit tight for 22mm plastic pipes?

Don't think so, they expand more lengthways, not an increase in diameter. Better to keep the holes in the joists smaller if possible.

 

[muggles]

Generally 25mm for 22mm pipe but if its a long run then 28mm

 

[newbuildinstaller]

32mm for everything!!!! im like a termite

 

[Whitespirit66]

Try to keep the holes in line with each other, and same distance from the top of the joist. Makes feeding the pipes through that little bit easier.

 

[McCombi]

If I remember correctly notches shouldn't be more than an eighth of the joist depth, no notches on joists with depth of less than 100mm, not too near from an end support and shouldn't be in the join of a floorboard.

Thats from 6 years ago, whether its changed I don't know.

 

[sooey]

Try to keep the holes in line with each other, and same distance from the top of the joist. Makes feeding the pipes through that little bit easier.

They should always be the same distance from the top, on the centre line of the joist.