Damp course in Victorian terraced house with crumbling mortar??

[a1993h]

Hey everyone,
We own a terraced house built circa 1900 which has some serious damp issues in the front room. Went about taking back the plaster and render to install a chemical damp proof course. Started hacking away at the wall and reached the original red brick wall. The bricks were felt quite damp and the mortar was damp and very crumbly. Not sure where to go from here..

I'm wondering what the best way to go about applying the damp course will be. Should it still be applied to the mortar course even though it's badly deteriorated. Also, will the brick wall have to be re-pointed before rendering?

Thanks!

 

[a twig]

Before you get too stuck in, it’s worth identifying the cause of the damp - an injected DPC and then tanking / re-plastering isn’t cheap and won’t fix the root causes, it will just hide the symptoms for a few years.

Broadly, no matter your house, the rules are the same. As a rule of thumb steps 1 & 2 are the cause of the majority of damp issues.

Stage 1 - External
1) Check and resolve any sources of external water ingress at the top (failed roof, gutters, gullets, roof valleys etc) - go out in the rain with a brolly and see what all your gutters and downpipes are doing, look for water sheeting down the walls.

2) Check exterior vs interior ground levels and sort as far as possible (exterior should be lower, preferably at least 200mm but not always practical, but definitely below your DPC if you have one) and make sure all services, waste water, guttering down pipes etc are behaving and going where they should with no leaks

If you find issues, fix them and then wait, houses can take months to dry out (one month per inch of wall thickness is often a good guide)

3) Renders - if your house is rendered - ascertain what it is rendered with and whether it might have failed - look for cracks, bubbling or blown paint etc. If it’s a cement based render then it is usually recommended to remove it and re-render in lime.

If all that looks as it should then take a look inside.

Stage 2 - Interior
If there are still problems then move on to tackle the inside

Floors:
If suspended are they properly ventilated? Are there service leaks in water/waste pipes underneath?
If solid, how are they constructed? Modern concrete floors may be forcing moisture into the walls, later coverings might be preventing earth or stone floors from breathing etc.

Walls:
Make sure that internal finishes are breathable - remove / replace gypsum or cement based plasters and vinyl paints where necessary

 

[stuart45]

Are they solid or cavity walls?

 

[a1993h]

Before you get too stuck in, it’s worth identifying the cause of the damp - an injected DPC and then tanking / re-plastering isn’t cheap and won’t fix the root causes, it will just hide the symptoms for a few years.

Broadly, no matter your house, the rules are the same. As a rule of thumb steps 1 & 2 are the cause of the majority of damp issues.

Stage 1 - External
1) Check and resolve any sources of external water ingress at the top (failed roof, gutters, gullets, roof valleys etc) - go out in the rain with a brolly and see what all your gutters and downpipes are doing, look for water sheeting down the walls.

2) Check exterior vs interior ground levels and sort as far as possible (exterior should be lower, preferably at least 200mm but not always practical, but definitely below your DPC if you have one) and make sure all services, waste water, guttering down pipes etc are behaving and going where they should with no leaks

If you find issues, fix them and then wait, houses can take months to dry out (one month per inch of wall thickness is often a good guide)

3) Renders - if your house is rendered - ascertain what it is rendered with and whether it might have failed - look for cracks, bubbling or blown paint etc. If it’s a cement based render then it is usually recommended to remove it and re-render in lime.

If all that looks as it should then take a look inside.

Stage 2 - Interior
If there are still problems then move on to tackle the inside

Floors:
If suspended are they properly ventilated? Are there service leaks in water/waste pipes underneath?
If solid, how are they constructed? Modern concrete floors may be forcing moisture into the walls, later coverings might be preventing earth or stone floors from breathing etc.

Walls:
Make sure that internal finishes are breathable - remove / replace gypsum or cement based plasters and vinyl paints where necessary

Thanks for the in-depth reply. Think I may have gotten the hammer and chisel out prematurely before properly scoping our the exterior! The external walls are concrete rendered but there is a patch missing, leaving the original brick wall exposed.
I have also noticed that the low wall leading up to the house is missing coping stone. I wonder if water is building up here and contributing to the damp.
The guttering in the front is also pretty shoddy which could be a compounding factor!

Beginning to wonder if I should patch up the section of internal wall I've taken back and address the external issues. Any thoughts?

Thanks!

 

[Stevers]

Isn't that one boundary wall too many - any idea how that came about?

Is one of them yours? I only say that because my mother's neighbour had a Fleur de Lys Greek block wall built arse side to him be his then neighbour. When that nice bungalow in a decent garden was redeveloped (four large bungalows, lots of parking and tiny gardens) the builder put a fence up, so he now has a wall and a fence down one side of his front garden neither of them his.

 

[a twig]

You can leave it unpatched for now as it will help things dry out

 

[a twig]

Thanks for the in-depth reply. Think I may have gotten the hammer and chisel out prematurely before properly scoping our the exterior! The external walls are concrete rendered but there is a patch missing, leaving the original brick wall exposed.
I have also noticed that the low wall leading up to the house is missing coping stone. I wonder if water is building up here and contributing to the damp.
The guttering in the front is also pretty shoddy which could be a compounding factor!

Beginning to wonder if I should patch up the section of internal wall I've taken back and address the external issues. Any thoughts?

Thanks!
View attachment 15256View attachment 15257

I admit the first thing that came to my mind was the low wall was the fighting step to stand on when defending the main boundary against neighbourly incursions! I have clearly visited too many castles!

 

[a twig]

More seriously do you have a more zoomed out / wider photo of the front of the property? It looks like the front garden might be concrete/ paved and potentially bridging a DPC?

 

[Cubist]

Stevers is right, you do have an extra boundary wall there - which also seems to have been very poorly bonded into the wall of the house. That brickwork in the house wall is in a very shabby state and would be a probable source of the damp indoors. I would be exploring what might be needed to remove either the whole wall or the section meeting the house. The gap between those two walls will also be capturing water and any other rubbish that may also be contributing to the problems.