DIY Damp Proofing?

PaulZero

Hello! First post here, and hopefully there's enough detail here but if I've missed something please let me know and I'll do my best to fill in any gaps.

So I own an early 20th century (~1916) brick end terrace in a wet and windy northern English town, and I've got some major grief with damp in the downstairs of my house along the exposed wall at the end of the terrace. I've pulled the carpets up in my living room to expose some rather rotten looking floorboards in the alcoves either side of my chimney, with wet patches occasionally showing up on the currently bare plaster on the chimney breast, these seem to go up about 1.5m and then stop. In the kitchen the same wall is lined by floor level cabinets and my oven. In the cupboards there's a strong smell of damp which clings to just about anything you leave in there.

The kitchen floor is concrete with tiles, whilst the living room is a suspended timber floor with approximately 2 feet of void below. The house had cavity wall insulation installed < 10 years ago.

I had a quote to fix this 2-3 years ago (yes the problem has festered since then, no that isn't clever, but life gave me some bigger things to worry about) and it came to about £1500 from a bloke who saw the house fully furnished and wall papered (and thus in my mind no idea of the actual damage which I've since exposed). This is a very large sum of cash, which to be honest I can't see going any lower now I know the extent of the rot, so I'm looking to do this myself if it's possible.

I chatted with my property developer neighbour about this briefly a couple of years ago, and from what I recall he blamed the cavity wall insulation (and its wonderful bridging effect) and suggested I strip the interior plaster tank the walls myself. Off the back of my own research and other threads I've seen on here I'm thinking I'll also need to possibly dry out and apply some kind of water repellent treatment to any floor joists that are touching the external wall? I guess I'd like to know if doing this DIY is perfectly fine, or if there's a good reason damp proofing costs so much?

If you read all that, thank you, and if you've got any ideas on what I could do to remedy this without racking up a four figure bill thanks again.

Doozergirl

You shouldn't be tanking. You should be removing whatever is causing the issue, allowing the house to dry, fixing any irreparable damage and redecorating.

If you were standing under the shower, you wouldn't put a raincoat on, you'd turn the shower off. Same for houses. Stop the cause and solve the problem, not disguise it - it continues to do damage and will reappear later.

Have you removed the cavity wall insulation? That's the first step. Isn't there a thread somewhere for making a claim against the people that shouldn't have installed it?

Post us some pictures of the outside of the house too, in case there's anything else that's obvious to us .

PaulZero

Doozergirl wrote: »

You shouldn't be tanking. You should be removing whatever is causing the issue, allowing the house to dry, fixing any irreparable damage and redecorating.

If you were standing under the shower, you wouldn't put a raincoat on, you'd turn the shower off. Same for houses. Stop the cause and solve the problem, not disguise it - it continues to do damage and will reappear later.

Have you removed the cavity wall insulation? That's the first step. Isn't there a thread somewhere for making a claim against the people that shouldn't have installed it?

Post us some pictures of the outside of the house too, in case there's anything else that's obvious to us .

Thanks for your reply, that makes a lot of sense and I certainly don't want to just cover the damage up. I knew my old neighbour was awful, but glad I didn't follow his building advice. The cavity wall insulation is still in as far as I know, I have the guarantee certificate somewhere along with some scribbles by the person who installed it.

Will get some photos and post shortly if it allows me (I did have a crude floor plan detailing where the damp was but it didn't let me link to it because I'd only just joined).

I should point out I don't have any conclusive proof that the cavity wall insulation is the cause of my damp issues, however from what I've read it's not advisable in properties that'll take a lot of abuse from the weather (which an end terrace on the coast of Cumbria probably will at least half the year).

PaulZero

I've created an album of photos of the side of my house. Possibly the most exciting collection of photos I've ever made...

https colon slash slash 1drv.ms/u/s!AqviG7_9APZPhuFagjLHLCJYpJ6Ujw?e=yHrO3k

One thing I've immediately noticed is how shocking some of the pointing is, that certainly explains some of the problem I think?

I had to do silly things with the URL because I'm a new member, my apologies to the admins / mods but I hope you will agree I'm not attempting to spam anything here.

FreeBear

PaulZero wrote: »

https colon slash slash 1drv.ms/u/s!AqviG7_9APZPhuFagjLHLCJYpJ6Ujw?e=yHrO3k

One thing I've immediately noticed is how shocking some of the pointing is, that certainly explains some of the problem I think?

Your link redirects to https://onedrive.live.com/?authkey=%21AIIyxywiWKSelI8&v=photos&id=4FF600FDBF1BE2AB%21110810&cid=4FF600FDBF1BE2AB

The pointing does indeed look shot in places. Not unexpected with lime mortar that is suffering from damp. I also don't see any evidence of a damp proof course (DPC). It may be below the surface of the side passage (which I see slopes from front to back). Can you dig a trench along the side of the wall and install a french drain ?

JimmyChanga

As said already, fix the reason.

Chisel out some pointing and see if you can find a DPC.

The cavity wall insulation may not be an issue. Depends.

Doozergirl

There isn't a huge amount to look at there. Freebear's covered it.

I guess getting into the wall with an endoscopic camera would be of interest to me at this point. See what the insulation is up to and what else is in there.

Retrofitted cavity wall insulation isn't an area I know much about.

stuart45

Looks like you have Struck pointing, rather than Weather struck, which is more common on an exposed flank.

PaulZero

FreeBear wrote: »

The pointing does indeed look shot in places. Not unexpected with lime mortar that is suffering from damp. I also don't see any evidence of a damp proof course (DPC). It may be below the surface of the side passage (which I see slopes from front to back). Can you dig a trench along the side of the wall and install a french drain ?

I don't believe I own the tarmacked side passage, I expect the council may get really angry if I start digging out drains. However if the DPC does exist, and it's below the alley, is it not basically pointless since it's effectively underground?

JimmyChanga wrote: »

Chisel out some pointing and see if you can find a DPC.

Since the pointing is already a bit of a state I'll go and have a look later today, and see what's lurking. From what I've read I'm guessing you mean a physical barrier such as slate or a membrane, which I will find if it's there. I'm guessing given the lack of obvious drill holes anywhere there's no chemical DPC?

Doozergirl wrote: »

I guess getting into the wall with an endoscopic camera would be of interest to me at this point. See what the insulation is up to and what else is in there.

This occurred to me but my last camera was rubbish. Thank you for the excuse to buy a new one, I will look into getting a new one and take a peek inside the walls when I'm able.

stuart45 wrote: »

Looks like you have Struck pointing, rather than Weather struck, which is more common on an exposed flank.

Thanks for the insight, I'll definitely ask anyone I get out to look at the pointing about the method they'd employ given the exposure to weather.

JimmyChanga

Since the pointing is already a bit of a state I'll go and have a look later today, and see what's lurking. From what I've read I'm guessing you mean a physical barrier such as slate or a membrane, which I will find if it's there. I'm guessing given the lack of obvious drill holes anywhere there's no chemical DPC?

Yes, you'd expect a slate DPC for the age of the house. Could be something there that has been mortared over.

Also you can lift a floorboard inside and look for a DPC. It might be below that tarmaced path.

markin

The New air brick is under the floor boards isn't it? So the ground at the back of the house looks far too high.

I cant really see any drill hole pattern for cavity insulation. Should be easy to drill a hole on the inside and pull some out with some wire to see what it is, and if its dry.

The most common thing seems to be just to paint the bottom foot red or black