Plaster repair after leak.

[Silfi]

I would be grateful for advice on the remedial work required after a water leak.
My daughter noticed a very damp patch on an internal wall behind furniture. The problem was traced to a split cast iron waste pipe in the adjoining house (it is in the communal wall ). The insurance company removed the skirting and plaster and installed driers. However, after 3 weeks the driers were removed but they stated the wall is still "slightly damp". This is caused by rising damp and not covered by insurance.
My daughter got 3 quotes from preservation contractors. All want to inject chemical DPC over varying lengths of wall and replaster. If there is a DPC in the wall it must have failed is their verdict. The owner next door is going to replaster without any DPC treatment.
The wall is in the centre of the house well away from any external wall in an Edinburgh terrace built in 1878.

 

[Lorenzl]

I have been looking into a DPC for our next property and if you go that path do some research. From what I have read injected DPC is not that good:
It takes the easiest path and can leave gaps.
Takes time to inject and operators like to get the job done ASAP and don't wait long enough for it to penetrate properly.

If it is a communal wall could your daughter and the neighbour share the cost?

It is always a risk trusting the recommendation of somebody who is going to make money out of their advice. But if you can't check it yourself you are stuck; as I am!

 

[Doug71]

My mothers house has some damp issues, Timberwise came for a look and recommended injecting all the walls at a cost of I think nearly £3k.

A local independent firm came for a look, spent about 2hrs with me and pointed out things like a crack in some rendering and flat roof flashings etc that he thought could be the problem. He said to get those fixed and if the damp didn't clear up in a few months to get back to him. There was no charge.

Old houses were built differently, they had lime plaster etc and the walls could breathe.

There are a lot of dodgy damp proof firms out there.

 

[Sandyn]

Some pictures would be good. I would never trust what an insurance company says. They come out with all kinds 'excuses' to get out of paying a claim. Perhaps it will just take longer for the wall to dry out. Are you saying they stripped the skirting and plaster, but refuse to make good the work they did??
There was no rising damp before, so something doesn't add up.


Is it a stone wall? How thick is the plaster? is it direct on to the wall? Can you get under the floor to see the foundations. Builders at that time were really bad for throwing all the byproducts of building, old plaster, rubble etc into the foundations. This can assist damp rising from the ground. by bridging the crude damp proof course that was often used. Looks like bitumen and hair. I dug all the rubble away to assist the foundations breathing. Is there enough underfloor ventilation? There may be a simple solution, but need some more info first.

 

[Bingy man]

I would be grateful for advice on the remedial work required after a water leak.
My daughter noticed a very damp patch on an internal wall behind furniture. The problem was traced to a split cast iron waste pipe in the adjoining house (it is in the communal wall ). The insurance company removed the skirting and plaster and installed driers. However, after 3 weeks the driers were removed but they stated the wall is still "slightly damp". This is caused by rising damp and not covered by insurance.
My daughter got 3 quotes from preservation contractors. All want to inject chemical DPC over varying lengths of wall and replaster. If there is a DPC in the wall it must have failed is their verdict. The owner next door is going to replaster without any DPC treatment.
The wall is in the centre of the house well away from any external wall in an Edinburgh terrace built in 1878.

I’m assuming that the damaged pipe has been repaired,? how much plaster did they removed? I’m not an expert on this subject but if your neighbor is not going to have the damp proofing done then it’s unlikely to be fully effective if you do . I think I would wait a few weeks to see if the wall drys out fully. A moisture meter will help confirm this . As Doug has said there can be many other factors that can cause damp - one of the biggest issues and often overlooked is the gutters and down pipes. Also the external walls - is the damp course visible and is it above any slabs , decking , concrete etc . Are are the external drains in good condition ( not blocked or restricted) does rainwater collect around the base of the building during heavy rain. An 8-10” border around the base of the building filled with 3-4 “ of gravel can help to disperse any excess water if this is the case. Back to the wall in question if it continues to dry out then I’d probably just have it re plastered or even dry lined rather than spend a few thousands on dpc treatments. One final point is that water can travel and find it’s way into a building and show up several meters from where it originally got in .

 

[NormanB]

The diagnosis of rising damp should be viewed with suspicion. A whole industry has been built up with expensive snake oil solutions around flawed diagnosis.

Have a look at Peter Wards channel on You Tube- he has a playlist with scores of videos on the ‘damp’ subject and as he reveals yes there is a ‘damp’ problem but it is rarely ‘rising damp’.

Here is one example:

 

[Lorenzl]

Thanks for that link @NormanB very interesting.

 

[Silfi]

Thanks to all who have replied.
To answer a few of the questions raised ---
It is a brick wall that appears to be single thickness as no headers visible from either side. I estimate the overall thickness at 450mm including 40mm thick plaster on each side. As the area of damp was the same on both sides there would not appear to be any cavity. It is plastered directly onto the brickwork.
The damp area was approx 2m long and 1m up the wall. The insurance company had 4 driers (dehumidifiers?) operating for 3 weeks. They will reinstate the skirtings and replaster but if rising damp has not been treated then no guarantee.

 

[Bingy man]

It’s starting to sound like an ingress of water issue ( eg water leaking possibly from this damaged pipe ) rather than r/ damp. I’ve not seen r/d in just one specific area and I’d expect damage to the woodwork-flooring if suspended, skirting boards etc . For me the giveaway would be a constant smell . In all my years working in other peoples homes and the 20 or so years I grew up in a pre-war terraced house that smell is unmistakable. Also black mould on the wall which will transfer to nearby surfaces and never goes away . Built in 1875 you say yet your daughter recently noticed the damp patch - I’m pretty certain there would of been other evidence of r/d long before the actual damp patch . Sounds like a cop out from your insurance company and a rip off attitude from the builders who have quoted . I’m thinking you told the builders of the insurance companies diagnosis and they are taking their word as gospel as they could be held responsible if the problem was to return. Leave the area exposed, dehumidifiers are cheap to hire and see how much water ( if any ) it collects. I’m with your neighbor tbh as without any other indication that it’s r/ damp why spend 2-3 thousand pounds. Illuminate all other possible causes . Does this house have a cellar? the area in question will not be to expensive to re plaster so that’s what I’d probably do once I’d illuminated all other possibilities.

 

[rafezetter]

My mothers house has some damp issues, Timberwise came for a look and recommended injecting all the walls at a cost of I think nearly £3k.

A local independent firm came for a look, spent about 2hrs with me and pointed out things like a crack in some rendering and flat roof flashings etc that he thought could be the problem. He said to get those fixed and if the damp didn't clear up in a few months to get back to him. There was no charge.

Old houses were built differently, they had lime plaster etc and the walls could breathe.

There are a lot of dodgy damp proof firms out there.

Indeed I've seen some terrible work done by DPC injection companies including where they had drilled into the BRICKS to add the chemical DPC.

Engineering bricks.

Not suprinsingly it didn't work.

I would advise hiring a company that guarentees thier work, in WRITING.

 

[thetyreman]

it's the pipe that needs fixing, I would recommend watching all of peter wards videos, like he says 9 times out of 10 it's another issue like leaky pipes, poor airflow, leaky drains from old cracked pipes are a common cause of it, don't listen to the insurance company, get a second opinion.

 

[John Brown]

Thanks to all who have replied.
To answer a few of the questions raised ---
It is a brick wall that appears to be single thickness as no headers visible from either side. I estimate the overall thickness at 450mm including 40mm thick plaster on each side. As the area of damp was the same on both sides there would not appear to be any cavity. It is plastered directly onto the brickwork.
The damp area was approx 2m long and 1m up the wall. The insurance company had 4 driers (dehumidifiers?) operating for 3 weeks. They will reinstate the skirtings and replaster but if rising damp has not been treated then no guarantee.

I'm not a bricklayer, but I think there are no headers visible in cavity walls.
Sorry, just re-read the post and saw it's an internal wall - ignore me!

 

[MikeJhn]

!. Rising damp is a myth.
2. Neighbours pipe they should repair the fault and all consequential damage.
3. Communal wall, by this I assume you mean a party wall, was a party wall surveyor appointed? Any qualified surveyor will know that Rising Damp is a myth and will put the neighbours insurance company surveyor (if there was one) in their place re the guarantee, has your daughters insurance company been informed/involved? Important, they insure the risk to your daughters property.

Meanwhile ask the neighbours insurance company why there is a lack damp elsewhere on this wall, if indeed as their conjecture it is Rising Damp, or leave this to your daughters insurance company's surveyor who should be involved.

They will tell them that in their opinion the saturated ground under the pipe has not dried out sufficiently and any further issues will be referred to them for remedial works to be carried out.

All the above should be in writing , you may find that your daughter has been dealing with the builder and not her neighbours insurance company, important to not let this issue die until resolved, your daughters house is her most expensive/important possession and should be treated as such.

 

[Lard]

Any qualified surveyor will know that Rising Damp is a myth

Yes, I would agree with your suggestion to ask a surveyor.

I’m a version that retired a few years ago and have seen plenty of examples of rising damp, as did all of my colleagues.

I would suggest that any other uncorroborated comments are labelled as opinions and not purported as fact.

 

[MikeJhn]

I was a Chartered Engineer that worked and consulted to the Insurance Ombudsman and never saw a genuine case of rising damp, lots of damp that could be explained, but never one of rising damp.

 

[baldkev]

As above if there wasnt a problem before, its not rising damp. Also, we are in the middle of an extremely dry period...... so n9t much moisture in the ground.
Definitely due to the pipe in my non expert opinion

 

[Sandyn]

I was a Chartered Engineer that worked and consulted to the Insurance Ombudsman and never saw a genuine case of rising damp

Let me help here

 

[Sandyn]

I estimate the overall thickness at 450mm including 40mm thick plaster on each side.

Surely that must be a cavity wall?? something doesn't add up. They wouldn't build a 450mm thick brick wall?? sounds like two leaf with cavity.
Can you get a long masonry drill and put a hole through from your side, but not all the way through, see if you find a cavity. If it was me, I would remove a brick or two to see if it reveals any more info. It will probably be lime mortar, so easy to scrape out.


Both houses had similar damp patch on the inner wall. Never any damp problem before. Leak supposedly found in cast iron pipe going into the wall. Wall doesn't dry out properly after leak fixed.
In this case, I don't believe it's rising damp There could be a leak above and the cracked pipe was assumed to be the problem.

Worst case, 40mm plaster depth is enough to replace with batons and plasterboard.

 

[davethebb]

As MikeJnn highlighted it is very unlikely to be rising damp. If the leak had been there for a while, which is likely as it takes time to penetrate the brickwork/ground below, it will take months (6 - 12 months) to dry out - using dehumidifiers on site for three weeks will not be enough. I would remove a good section of the plaster (ask the neighbor to do the same) and make sure you have good airflow (if need be use some small fans) and leave for 3 to 6 months and then review ( perhaps buy a cheap moisture meter and just take some reference readings so you can see what is happening). Do not replace any plaster, until most of the moisture has gone, and then use lime plaster.

 

[Sandyn]

for drying a wall, a simple fan is enough. You don't need the dehumidifier, especially at this time of year. After a few days, it will appear dry, but more moisture may come to the surface.