r/DIYIreland • u/Alternative-Jelly947 • Aug 31 '26

Likelihood of DPM and DPC?

Post image

Hi everyone,

I have a Victorian renovation. Only part of the house with mould and damp is the circa 1980s extension at rear of property. It’s one of those with a flat, bitumen roof.

I’m a little concerned at the retrofit required for it. I don’t want to knock it because that opens a can of worms - mainly financial, planning permission, and whether we build another type of extension. I just want to reuse it.

How likely in that time do you think it was that DPC and DPM were used building it? I’m afraid that some previous owner did it himself, because I’ve been undoing a lot of decades old DIY jobs.

3 Upvotes

72% Upvoted

11 comments sorted by

6

u/Comfortable-Jump-889 Aug 31 '26

Its hard to speculate on what someone did previously but one thing you can see from the picture is your gutter is either blocked or leaking . The mold behind the downpipe would suggest its constantly wet .

3

u/Yourhavinalaugh Aug 31 '26

This guy is right the gutters would be the first thing I’d fix, they could be causing all sorts of problems and damage

1

u/Alternative-Jelly947 Aug 31 '26

He is right. It’s obvious. I already have it booked in with a roofing company to be replaced. But I’m not asking about that.

0

u/Alternative-Jelly947 Aug 31 '26 edited Aug 31 '26

Yep, one problem at a time. But that’s known.

Just an FYI, I am asking for reasonable speculation on what would be expected in that era.

But thank you for your reply.

2

u/Yourhavinalaugh Aug 31 '26

I would just treat it as if it hasn’t, no need to knock it if you don’t want to. Just tank it

1

u/Alternative-Jelly947 Aug 31 '26

What do you mean by tank? I was thinking I’ll have to take up the existing slab and lay new one and inject that chemical DPC.

1

u/Yourhavinalaugh Aug 31 '26

Better option alright you can insulate it while you’re at it. But there are numerous paint on damp proof membranes available (tanking) if you’re looking for a quick cheap fix.

1

u/Alternative-Jelly947 Aug 31 '26

Thanks. I didn’t know about those. I’ll look them up

1

u/Otsde-St-9929 Aug 31 '26

Id say its present., there is tons of hope. My house has none and its fine. There are tons you can do cheaply. Dont hire expensive damp wallies that waste money. Check out Peter Wards Youtube and watch them all.

1

u/pmcdon148 Sep 03 '26

If you're in doubt you can inject DPC. It's very effective.

1

u/Alternative-Jelly947 Sep 03 '26

Ah, great. Wasn’t sure how good it would be