I’ve searched through the forum for similar issues but I would appreciate some advice on our particular situation.
We have an ongoing issue with damp walls in our Victorian end-of-terrace house (built circa 1890) in SE London. The plug socket in the kitchen about 12" from the floor had to be disconnected recently as it was found to be damp and constantly tripping the fuse box and the wall is crumbling around it. There are areas of the wall that appear darker and there is evidence of salt on the walls. Similarly, in the bedroom above the kitchen there are some patches of blown plaster and the paint appears darker in some areas.
Our house was a mid-terrace but the house next door was damaged by bombs during the second war and knocked down so our house is now an end-of-terrace. What would have been the internal chimney stacks of the neighbouring property are still in place and can be seen to jut out from the side wall. Where the internal chimney stacks were removed on our side, they were not removed from the loft. In the loft the brickwork from the old chimneys appears to be covered in salt.
We had an independent damp survey conducted and the surveyor said that although the chimneys had been removed, lots of hygroscopic salt within the walls had been left behind.
His recommendation was that we should have the plaster hacked off from the kitchen and bedroom walls and replaced with either:
1. A 3 parts sand to 1 part cement mixture with gauging water and a waterproofing agent such as Sika 1 (2 coats) before a third skim coat
Or
2. A Newton wall membrane covered with a skim coat
There is an area of the external wall where the render has blown quite badly that we will also need to get repaired. This is on the old neighbouring middle chimney stack.
There are other areas in the house on that side wall that show smaller signs of damp and where the plaster has blown but they seem to be far less of a problem.
We have subsequently had a couple of plasterers round to quote to do the work and one of them has pointed out that there may be some potential issues with the chimneys/roof:
1. The flaunching on the rear chimney (at the back of the house) wasn’t sloped enough so that rainwater could potentially be sitting on top of it rather than running off.
2. The 2 half-round hood tops that are sitting directly on top of the middle chimney, not those sitting on top of the chimney pots, are not correct and could be allowing rainwater in. I’m not sure of my terminology here, but hopefully this makes sense.
3. The coping stones have been incorrectly fitted and are too close to the wall, meaning that rain drops back onto the wall, rather than away from the wall.
4. I also noticed myself that the pointing on the rear chimney when viewed from the rear garden looks like it needs some repair.
From the photos I’ve provided do these seem like things that need doing? We did have a lot of work done to the roof and chimneys when we moved in 4 years ago. To me it seems sensible to deal with the flaunching and the pointing on the rear chimney and to get the blown external render repaired. I’m not sure that anything needs doing re point 2 or point 3 though? The chimney stacks on the neighbouring side do not appear to have any ventilation either at the top or bottom - should they be ventilated?
I understand the concept of the salts within the chimney attracting moisture, but it would seem to me that that moisture must be coming from somewhere external? Or is it just as likely that moisture inside the house is being soaked up by these salts in the walls?
If we get the walls replastered internally with either the waterproof mixture or the waterproof membrane is this just going to move the moisture elsewhere?
Neither of the plasterers we spoke to had used the damp membranes before and would use the Sika method. If I understand correctly they would not be just removing the old plaster but also removing all of the internal wall back to the bare brick.
Any thoughts on what the most sensible next steps should be would be much appreciated.
I do have other photos but I seem to only be able to add 3 files to this post.
We have an ongoing issue with damp walls in our Victorian end-of-terrace house (built circa 1890) in SE London. The plug socket in the kitchen about 12" from the floor had to be disconnected recently as it was found to be damp and constantly tripping the fuse box and the wall is crumbling around it. There are areas of the wall that appear darker and there is evidence of salt on the walls. Similarly, in the bedroom above the kitchen there are some patches of blown plaster and the paint appears darker in some areas.
Our house was a mid-terrace but the house next door was damaged by bombs during the second war and knocked down so our house is now an end-of-terrace. What would have been the internal chimney stacks of the neighbouring property are still in place and can be seen to jut out from the side wall. Where the internal chimney stacks were removed on our side, they were not removed from the loft. In the loft the brickwork from the old chimneys appears to be covered in salt.
We had an independent damp survey conducted and the surveyor said that although the chimneys had been removed, lots of hygroscopic salt within the walls had been left behind.
His recommendation was that we should have the plaster hacked off from the kitchen and bedroom walls and replaced with either:
1. A 3 parts sand to 1 part cement mixture with gauging water and a waterproofing agent such as Sika 1 (2 coats) before a third skim coat
Or
2. A Newton wall membrane covered with a skim coat
There is an area of the external wall where the render has blown quite badly that we will also need to get repaired. This is on the old neighbouring middle chimney stack.
There are other areas in the house on that side wall that show smaller signs of damp and where the plaster has blown but they seem to be far less of a problem.
We have subsequently had a couple of plasterers round to quote to do the work and one of them has pointed out that there may be some potential issues with the chimneys/roof:
1. The flaunching on the rear chimney (at the back of the house) wasn’t sloped enough so that rainwater could potentially be sitting on top of it rather than running off.
2. The 2 half-round hood tops that are sitting directly on top of the middle chimney, not those sitting on top of the chimney pots, are not correct and could be allowing rainwater in. I’m not sure of my terminology here, but hopefully this makes sense.
3. The coping stones have been incorrectly fitted and are too close to the wall, meaning that rain drops back onto the wall, rather than away from the wall.
4. I also noticed myself that the pointing on the rear chimney when viewed from the rear garden looks like it needs some repair.
From the photos I’ve provided do these seem like things that need doing? We did have a lot of work done to the roof and chimneys when we moved in 4 years ago. To me it seems sensible to deal with the flaunching and the pointing on the rear chimney and to get the blown external render repaired. I’m not sure that anything needs doing re point 2 or point 3 though? The chimney stacks on the neighbouring side do not appear to have any ventilation either at the top or bottom - should they be ventilated?
I understand the concept of the salts within the chimney attracting moisture, but it would seem to me that that moisture must be coming from somewhere external? Or is it just as likely that moisture inside the house is being soaked up by these salts in the walls?
If we get the walls replastered internally with either the waterproof mixture or the waterproof membrane is this just going to move the moisture elsewhere?
Neither of the plasterers we spoke to had used the damp membranes before and would use the Sika method. If I understand correctly they would not be just removing the old plaster but also removing all of the internal wall back to the bare brick.
Any thoughts on what the most sensible next steps should be would be much appreciated.
I do have other photos but I seem to only be able to add 3 files to this post.