Drilling internal to external wall?

DHR · 23 Mar 2025 at 11:21

I've seen very differing opinions on this, drilling from inside a property out, causing blowing of the external brick?

I was wanting to drop a couple of cables on the outside (side) of the house without messing with ladders etc. so in my case drilling inside to put on the upper floor, then dropping the cable that way?

aVdub · 23 Mar 2025 at 12:13

You will need to drill down to avoid water ingress as I am guessing you will not be able to seal it (ladders)

I've had all sorts of luck and bad luck when drilling in or out at customers houses in the past (sds 8mm & 10mm) If drilling out, try as much as possible to go out through the mortar course or an area that might not show.

Measure from an open window as much as possible for the depth and take off hammer when almost through.

DHR · 23 Mar 2025 at 12:17

Great advice thanks @aVdub

I was going to get someone around to do it, but, the last lot that did were BT engineers and they blew out the brick rotten when putting full fibre in, figured if anyone does it badly, it may as well be me :cry:

aVdub · 23 Mar 2025 at 12:20

Well, yeah that is true and like I say, it can be the toss of a coin if you blow a brick or not.

If you have a chance to go through with a smaller bit to start with, that can lessen damage when going through with the final drill bit.

Mercenary Keyboard Warrior · 23 Mar 2025 at 13:47

Great advice from av there I would say.

I would add, better drill* on drill only mode once your 80% or so through makes a diff. Let the drill do the work**, so bit more speed and give the bit a little time to cool every so often.
Clean out the hole unless your using a really powerful drill, it all helps with less friction and hence less resistance.

100% start with a small drill, less chance of blow out, but also its less work for the drill to do.
You can't get really long narrow masonry drill bits, but you can get 6mm in some of the top end stuff (such as rawlplug aggressor) which if your going to do this more than a few times is worth it.
Use a normal 6mm as deep as you can, then maybe a cheap longer one from a lesser make and just use the expensive one for the last chunk if you want to maximise its lifespan.

*Honestly there is a world of difference between even a low end SDS mains drill and a top end cordless.
** A lot of blowout is caused by people putting weight onto the drill on hammer action as its not going through fast enough.