Limit moisture after drilling hole

[my_name_is_slim_daisy]

Hello

Hope you’re all fine and dandy.

I’m having a few things like CCTV and Sirens mounted to the exterior. As this means drilling into the walls () I’ve been looking into how to limit moisture ingress.

I’ve read that any drilling should be done at an upwards angle (from outside in) which should create a drip path.

Some other things that might help prevent ingress:
- Feed the cable through a rubber grommet or weatherproof cable gland.
- Apply a UV-resistant external-grade sealant (e.g., silicone or polyurethane sealant like CT1, Sika, or similar) around the cable entry point on the outside face of the wall.
- Apply a small bead of sealant under wall-mounted bases (of sirens, CCTV) before screwing to the wall — this prevents rainwater tracking behind.

If you’ve seen any of my previous posts, you’ll know I’m a new home owner and most home improvement things - for me - are a first. So I’m wondering if any of the above are tried and tested…. or OTT. Also, is there anything I haven’t listed that might be worth looking into?

 

[trunky]

All that will help, most importantly you need a drip loop for the cables before they enter the wall.

 

[my_name_is_slim_daisy]

Thanks @trunky thats really helpful. I’ll watch a YouTube video (or two) on this.

Now I have to figure out how to tactfully supervise the engineer while they do this work. I don’t want them to feel like I’m breathing down their neck, but I need to make sure they’ve done as much ingress prevention as possible! I can either watch from afar with binoculars, or stick my head out the first floor window and watch them from there