Someone wants to drill through my damp proof membrane. Should I let them?

[SomeBozo]

I've read a few related threads here but not quite answered my question. I have pretty limited knowledge about this stuff. I have a DPM that was put in on a first floor wall (not wholly certain I wasn't taken for a ride) and then plastered over. It's not decorated yet though so that's something. A broadband provider wants to put a hole through the wall for the new cable and the logical place would be where this membrane went in. I raised it and they said "we'll seal the hole" and I'm sure they will externally at the brick, but will this impair the DPM and if so, enough for me to worry about?

I can always tell them to stick it (somewhere else), but if it's not a problem this would be the best place for it. I don't have pictures of when it was done but it looked like this:

Appreciate anybody who can tell me where drilling holes in a DPM sits on the 'NBD' to 'you've wrecked it line'.

 

[ETAF]

I have a DPM that was put in on a first floor wall (not wholly certain I wasn't taken for a ride) and then plastered over.

can you expand , a bit for the situation , i'm just a DIYer - so this maybe common, BUT i dont see why - is this because its near the ground with a basement or a flat of some sort - so although first floor - its still a few bricks off ground level

personally i would not want any damage to the DPl to occur and break the seal - but then i'm overally sensitive to this type of thing , as i hav eseen issues with damp because of DPC damage on a 1970's house , and had some railings redesigned when they wanted to drill exactly where the dampproof was located - but i maybe over the top

 

[jj4091]

If it is only a small ( 6mm?) I can't see there being a problem as long as they seal it properly with silicon inside and out and not just a rubber grommet Make sure they don't drill in from outside and make more of a hole than they need to on the inside.

 

[SomeBozo]

can you expand , a bit for the situation , i'm just a DIYer - so this maybe common, BUT i dont see why - is this because its near the ground with a basement or a flat of some sort - so although first floor - its still a few bricks off ground level

No. It's exactly what you imagine, a regular first floor at regular first floor flight. Though there is a floor above it. Hence me being a little suspicious as to why it was needed. There was definitely damp on the ground floor front and back, boards rotten too. Definitely needed work there. And they told me there was damp at the front on the first floor. Didn't really know anyone else in the area so went with their professional advice. (Special characters removed)

personally i would not want any damage to the DPl to occur and break the seal - but then i'm overally sensitive to this type of thing , as i hav eseen issues with damp because of DPC damage on a 1970's house , and had some railings redesigned when they wanted to drill exactly where the dampproof was located - but i maybe over the top

I'm of the same attitude - I'm super cautious about anything like this. Difference is I have no idea if I'm being super-cautious unnecessarily. I have the guy coming round in the morning so I'll discuss placement with him. There's an area without DPM but it's not as ideal but not the end of the world if it's best to avoid this.

If it is only a small ( 6mm?) I can't see there being a problem as long as they seal it properly with silicon inside and out and not just a rubber grommet Make sure they don't drill in from outside and make more of a hole than they need to on the inside.

Probably slightly larger than that. I'll check tomorrow but a bit of searching says 10mm is what BT use. It's a pretty thick wall as well - about 14" of brick, I think. It will definitely be fully sealed up after. They'll drill out from inside, yes. Though maybe that'll knock a bit of brick out for all I know. Probably still better way round to do it, though.

 

[Ivor Windybottom]

First floor or ground floor?

You'll have much bigger problems to deal with if the waves are lapping at your upstairs walls.

Was this membrane solving a specific issue?

 

[SomeBozo]

First floor or ground floor?

You'll have much bigger problems to deal with if the waves are lapping at your upstairs walls.

Was this membrane solving a specific issue?

First floor. And I was told there was some damp in that area there this would help with.

I don't know about the waves. Seeing a few fish swimming past my living room might be kind of relaxing. Like those hotels they have where your room is underwater!

 

[Ivor Windybottom]

If you really have damp in your walls on the first floor then perhaps look at the roof and guttering.

Drill it, it's unlikely it's really needed, or if it is then solve the actual problem.

 

[SomeBozo]

If you really have damp in your walls on the first floor then perhaps look at the roof and guttering.

Drill it, it's unlikely it's really needed, or if it is then solve the actual problem.

Thanks. There was some minor guttering and roofing issues and they were taken care of at the same time. Put some extra venting in that room as well since then.

I think given feedback here I'll probably try to put it somewhere else but if that's too much hassle with cabling it doesn't sound the end of the world so long as one modest hole and properly sealed.

Thanks all.

 

[^woody^]

It's unusual for that type of system to be necessary at first floor level, so the fundamental question would be whether any penetration of it would be an issue in context of the reason it was fitted. ie, in a basement, maybe on a wall above ground maybe not.

Bit a small cable hole resealed on the membrane in accordance with the manufacturer's guidelines should not be an issue.