What to do with Damp Internal Wall

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Hello,

I am after some pointers about what to do with a seemingly damp wall.

The core of my house is a cottage dating from the 1850s and the walls are brick built walls that seem to have a slate DPC. Most of these old cottage walls are now interior walls, as previous owners of the house had added numerous extensions.

I recently tried to open up the hallway by removing the cupboard under the stairs, and removing some old plasterboard in front of the cupboard under the stairs to expose the old wall. This can be seen in the below picture.

The old wall is seemingly damp at the base and extending a good metre or so up the wall. This is evidenced by flaking paint, soft crumbly brick work/lime mortar and very high damp meter readings. As mentioned this wall is now an interior wall, but it does have a metre or so of an extension added to it (in the 90's) which is an exterior wall.

So the question is, what do I need to do about the damp wall? The aim was to plaster it, but I presume we cannot plaster the wall until the damp issue is resolved?

Or would it be better just to paint the wall with some form of paint that allows it to breath naturally?

I do not think treating the wall with a modern chemical DPC would be practical as it would mean digging up the floor and also removing the majority of the kitchen, which is fitted to the back-side of the wall.

What do people advise? I want to end up with a nice decorated finish and a house that does not smell of damp. Given the wall has been in place for 150 years, I guess the damp is not harming it too much, but I do not want to make it worse by doing something dumb!

Thanks

TF

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It's possible it's rising damp if there's no way for water to evaporate out of either side. Is it damp under the floor? Are there any pipes that might be leaking in that area?
Presumably the damp is behind the paint rather then on the surface?
My thought would be strip off the paint and let it dry out, and see if it's getting any worse or if it's left over penetrating damp.
It's tricky to use a damp meter on masonry as the resistance is not predictable like wood, so you can get high readings because an area used to be damp or just because it's built with a different material.
If the wall is still getting damp and everything else is ruled out you may need to drill and inject a damp proof liquid, but try the other things first.
Good luck with it!
 
Hi John, thanks for the reply.

In response...

The floor in that area of the hall seems to be a concrete floor. The concrete gives a high damp meter reading. But that could just be the material.

There are no pipes in that area that I am aware of. The radiators are on a different wall, also the kitchen sink pipework is not on the back side of that wall (it is just cupboards on the other side of the wall). So there are no pipes that I am aware of in that vicinity.

With regards to the damp. The meter gives a high reading on both the paint and directly on the exposed brick, if that tells you anything...

How can you reliably tell if a wall is actually damp without using a damp meter (to help rule out previous dampness)?

Also what would be the best way to remove the old paint. Currently I would be looking at just using a wall paper scraper!

Thanks
 
I think you can get chemical test kits for damp, although there are some low tech ways.
One is to stick cling film on the wall and see if it gets condensation on the back. The other I suppose you could drill out a largish hole and collect the dust, then put it in a small pot with cling film on top and see if the cling film gets condensation on the inside.
You might have to store the pot in the fridge to make sure it's dry first, then add the dust while it's still in there and cover with cling film straight away. Sounds all of a bit of a faf though! Maybe other people have a simpler way.
To remove the paint just go for elbow grease.
 
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Hi.

Well i cover a portion of the wall with cling film, and over the course of a couple of days no condensation was seen on the film.

So perhaps it is not currently damp.

Presumably it will be ok to plaster!
 
OP,
You have a step-down, is the house on a hillside?
If plastic paint is on the wall then its wrong - if any paint, it should be masonry paint.
You can grind it off with an angle grinder grinding stone.

Given the damp solid floor & probable rising damp then you could FWIW drill and insert Dryfix chemicals - drilling from the exposed side only with a long bit. Be careful not to break through to the other side of the wall.
Then leave the brickwork bare - bare of render/plaster or paint.

FWIW: the underside of the stairs need two plys (sheets) of 12mm plaster board for fireproofing - stagger the p/board joins.
 
I think you can get chemical test kits for damp, although there are some low tech ways.
One is to stick cling film on the wall and see if it gets condensation on the back. The other I suppose you could drill out a largish hole and collect the dust, then put it in a small pot with cling film on top and see if the cling film gets condensation on the inside.
You might have to store the pot in the fridge to make sure it's dry first, then add the dust while it's still in there and cover with cling film straight away. Sounds all of a bit of a faf though! Maybe other people have a simpler way.
To remove the paint just go for elbow grease.
Hi J,
I get electronic components with a damp indicator within the sealed bag, here's a photo:

You would need to put it in a seal-able container, dry it out till the indicator showed blue, then put a measured amount of your damp drillings inside, and see what the reading is. Some experiments first to get the process.

Damp indicator Cobalt Chloride. http://www.ebay.co.uk/itm/25g-Cobal...152662?hash=item4639c88296:g:WlQAAOSwBahVRLJ4

C.
 

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