I need to put a 15mm central heating pipe through a brick wall - what drill size should I purchase? I'm thinking 20mm - though I don't want the hole to be too big! Should I seal the hole, or just let the pipe sit within it?
Should I sleeve the pipe in anything? If so, does it need to be thick? I could use some of those Rad-Snap thingys which just wrap around the 15mm pipe - or something similar.
Thanks
David