Neatest way to run 2x pipes through exterior wall

[Donkmeister]

In the past, when I've needed to run pipes through an exterior wall I've simply drilled a hole big enough for the next pipe size up and used a short length of pipe as a sleeve (e.g. 22mm pipe to run 15mm pipes through).

I need to run a pair of 15mm pipes through an exterior wall (brick cavity wall) and I'm acutely aware that if I drill two holes side-by-side then they will not line up exactly at both ends. I can guarantee there will be enough of a difference that I'll be unhappy with the way it looks.

I have core drills, so I could put a 40mm waste pipe in as a sleeve and squirt foam in there to prevent draughts, but is there something made for the purpose of passing pairs of 15mm pipes through walls whilst looking neat and minimising draughts?

 

[CBW]

What are the pipes carrying? Eg hot and cold, or heating?

 

[Donkmeister]

Bit of an unusual one... It's to carry cooling water for a PC outside to a radiator in summer to avoid making my office too hot. So the plan is to shut off and drain the external radiator in winter to avoid freezing and condensation issues.

So the hot side will only be 40ish Celsius... Never more than about 50 Celsius.

 

[Hugh Jaleak]

Get a long enough 15mm drill bit to go through the wall from one side in one go.

 

[Donkmeister]

Get a long enough 15mm drill bit to go through the wall from one side in one go.

I have long enough bits - the problem is drilling two holes that are aligned with one another at both sides.

Previous experience shows that over the course of a foot or so of brick wall, combined with very hard flint-rich bricks, the two holes that are aligned at one end will be 5-10mm out of alignment at the opposite end.

 

[oldbutnotdead]

As above, and make a jig ( for jobs like that I have a lump of 4 x 4 with perpendicular holes in) so you drill straight and level.
If it's only 1 side that you care about, drill from that side- if it's both then start with a long 6mm all the way through (using the jig), when you're through use the jig clamped on the opposite side of the wall to drill back full bore (jig will let you start off-centre if drill has wandered)

 

[fixitflav]

I have long enough bits - the problem is drilling two holes that are aligned with one another at both sides.

Previous experience shows that over the course of a foot or so of brick wall, combined with very hard flint-rich bricks, the two holes that are aligned at one end will be 5-10mm out of alignment at the opposite end.

Why not drill all the way through from one side for the first hole, then drill from both sides for the second hole?

 

[Donkmeister]

Why not drill all the way through from one side for the first hole, then drill from both sides for the second hole?

That's a very good idea, thanks! Thinking about it, if the second hole is wonky I can go up a drill size to get the pipe through straight.

 

[fixitflav]

That's a very good idea, thanks! Thinking about it, if the second hole is wonky I can go up a drill size to get the pipe through straight.

Glad to help. It's easy to sometimes miss the obvious solution.