Damp plaster on internal wall 1m above DPC

KarrieP

Hi,
I'd be grateful for some advice please.
We have a huge damp area of plaster on the dividing wall between us and next door (1920s semi, solid walls). The first signs appeared through the vinyl wallpaper, small rust-like marks 2 years ago followed by the wallpaper starting to lift off the wall. It is a large kitchen diner so we kept putting off redecorating as it will be such a big job. Recently it became clear that the plaster was crumbling behind the paper.

So, today I pulled the paper off to investigate and am a little daunted by what I've found. It is approx 1m x 2m. A DPC was done before we bought the house 5 years ago. The newer plaster, from the DPC being done, up to 1m high is sound and unmarked, above it is a horizontal band of damp, salty plaster with some areas crumbling off.

The bare bricks in other areas of the house (cellar and utility) have lots of salty deposit but nowhere else has any signs of damp.

I emailed the DPC contractor and they want to charge for re-inspection. From other threads I gather this is usual but that they will do all they can to convince me that it is a different cause rather than failure of the DPC.

What I'm wondering is whether this is likely to be failure of the DPC, or whether it is just that the old plaster was compromised, or whether it is a problem with the bricks behind the plaster... and what to do about it!

Thanks for reading.
If I can work out how to post a photo I will.

smifffy1989

photo may assist!

You say it is not near the damp proof course? It could be a leak in pipework, ask your neighbour if they have a similar problem.

KarrieP

trying to post a link:

instagram.com/p/ruzOvWw_ZY/

spannerzone

What's on the other side of this wall?

I would expect very little help from the people that did the DPC, dare I say that many don't even believe in rising damp!

Do you have a kitchen extractor? do you dry clothes indoors etc? does this only happen when it rains? etc.

I found this site very good reading with my damp walls

KarrieP

Hi,
the other side of the wall is next door, this is the dividing wall so no contact with rain. The room above is a bedroom with no damp. The image shows the end of a long wall, at least 8m, and this is the only patch. The room beyond the internal door is a single story utility which has bare brick walls which are 'salty' and crumbly. I think this was an old outhouse originally. I'm wondering if the damp is migrating in horizontally behind the door frame.

Yes, we use an extractor and no we don't dry clothes in here.
Thanks.

NewtoDIY

KarrieP wrote: »

Hi,
the other side of the wall is next door, this is the dividing wall so no contact with rain. QUOTE]



You should go straight over to your next door neighbours and ask them if they have damp there, or whether there is a bathroom or sink/toilet there. There might be a leaking pipe somewhere that is slowly dripping.


That damp has come from somewhere. I think if it was rising damp and the DPC had failed, you would see some sign of damp in the newish plaster. But that looks localised to me which suggests that something specific is causing it.


You've got a cat flap on that photo which suggests that is a door leading to outside. The damp in your photo goes all the way along. Have you been outside and had a look to see if your gutters have failed or something is causing rainwater to saturate the walls?

Ader1

So rare is rising damp that some even argue that there isn't such a phenomenom.

How about condensation?

KarrieP

NewtoDIY wrote: »

KarrieP wrote: »

Hi,
the other side of the wall is next door, this is the dividing wall so no contact with rain. QUOTE]



You should go straight over to your next door neighbours and ask them if they have damp there, or whether there is a bathroom or sink/toilet there. There might be a leaking pipe somewhere that is slowly dripping.


That damp has come from somewhere. I think if it was rising damp and the DPC had failed, you would see some sign of damp in the newish plaster. But that looks localised to me which suggests that something specific is causing it.


You've got a cat flap on that photo which suggests that is a door leading to outside. The damp in your photo goes all the way along. Have you been outside and had a look to see if your gutters have failed or something is causing rainwater to saturate the walls?

Thanks,
the cat flap is in the internal door and leads to a porch where there is another cat flat leading to outside The wall that is shown continues for another 6 metres, through the porch and then utility room, a continuous dividing wall to neighbours.

There are DPC holes in the porch but it must have been done at a different time to the one in the kitchen as it isn't detailed on the guarantee document.

I've emailed the DPC contractor to request a visit and will speak to the neighbours...

Thanks for your input

spannerzone

I think it's a safe bet to say the DPC company will find this isn't anything to do with their previous work but no doubt can offer another solution for small (large) fee.

Even if rising damp was the problem (and many doubt rising damp is a real problem anyway) it seems unlikely to manage to get halfway up a wall without starting at the bottom.

Obviously depends on the building but leaking gutters, leaking roof, leaking pipes or such like could be the cause...water can travel along weird and wonderful routes so don't assume it's coming from directly above the damp area.

Spending a little time investigating may save you time and money from 'damp specialists' that will always find damp and have a solution for you that probably won't cure the actual problem. Did you read the link I gave earlier for more ideas on solving damp?

cyclonebri1

Any thing you do is pointless until you have seen what the effect is next door, if they don't have an issue it won't likely be rising damp.

I too subscribe to the view mentioned earlier about RD not even existing, penetrating damp is much more likely.

KarrieP

spannerzone wrote: »

Did you read the link I gave earlier for more ideas on solving damp?

Yes, thank you. It seems likely that the plaster higher up the wall was not done by the DPC specialist so wasn't the correct specification and has been damaged by residual damp and salts.

Also, the wallpaper was a horrid vinyl overpainted with an eggshell finish which wouldn't have allowed the wall to breath... the plaster is noticeable dryer now it is stripped off. However, this wallpaper is all over the wall and this is the only place it is damp... so I'm not convinced by the 'walls need to breath' theory yet. They only need to breathe if they are damp, but I'd rather solve the damp problem.

Not managed to catch the neighbour yet.