Pre-Drilling holes in Brickwork

[IanB]

With a new build it seems a shame to puncture the fabric by drilling holes through walls after the fact. To that end can holes be factored in whilst brickies are building up to plate level?. I am personally thinking things like heat pump connection pipes, MVHR exhaust to outside and external water taps

 

Can these sort of things be pre-planned so that at the very least a tight hole(s) can be made into the inner and outer bricks/blocks at build time

 

Thanks

[Russell griffiths]

You could build in a rigid plastic duct for the heat pump pipes, make sure you get the correct diameter insulation around the pipes so you get the correct size duct. 
 

but then what happens when the heat pump installer doesn’t like the location, unless you are getting him involved now to give you the location then just core drill them out, you won’t see the holes as the amount of insulation around the pipes is huge. 
 

the only thing you mentioned that it’s worth building in would be the MVHR ducts, pick up the exhaust and fresh ducts and build them in. 
you will still need to fit a collar or tape them to your vapour control layer as mortar will shrink back and leave a gap. 

[torre]

I don't think it's worth trying to 'build in' any sort of hole - you'll get a better result from core drilling with the right diameter in the right place later.

 

I think it only cost us a couple of hundred quid to get a specialist core drilling company in with a decent rig who drilled all the MVHR, soil and waste penetrations for us - really neat, zero dust, consistent slight downward angle to avoid bridging the cavity.

[-rick-]

I've not had the chance to build yet but my planning was always to do the holes early as the walls went up. Likely with preplaced pvc tubes with some form of sealant ring concreted in using formwork (blockwork wall). Why? Seen that suggested as a much better way to get long lasting airtightness vs trying to seal up holes later.

 

PVC making a nice route through insulation and easy to seal to pipework/cables (and easy to pull the pipework/cables out and replace).

 

Obviously need everything preplanned and relies on careful placement (hidden by cladding/other). Likely overkill. If people preplan routes through slabs then you can do the same through walls but I'm probably overthinking it.

 

Even if you don't premake the holes, for airtightness reasons I think it's a good idea to really plan out penetrations ahead of time. I've seen too many on youtube start with great airtightness intentions and then end up drilling holes all over the show (lights, antennas, CCTV, etc, etc). Yes the airtightness can be addressed but if you can plan ahead and minimise penetrations then it's less work.

 

All that said, all my thoughts are based on a DIY heavy approach. If paying contractors, this method likely gets very difficult.