How bad is this damp and how much roughly will it cost?

Benjamin2021

Hello, we bought this house last month. We have now found this damp. Here are the photos. (The second photo is looking sideways across at the neighbours' walls so you can compare.) The width of the part of the back wall with visible damp on the inside is ~2metres and as you can see the worst part is on the bottom half of that.
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The house was built in the 1930s and is a terrace. 
The Homebuyer Survey said there was no sign of penetrating damp, so we are quite surprised to see this. 
Does anyone have a sense of (a) how bad this is, (b) what we might need to do to fix it and (c) how much that might cost? 
Thank you!

Benjamin2021

I should have added: on the external photos the damp patch on the inside is the bit directly between the windows. As you look at them from the outside the window on the left (bigger one) is the one you can see in the bedroom with the damp; the window on the right (smaller one) is in the bathroom which is the next door room. 

neilmcl

If the homebuyer survey missed that then I'd be inclined to take some legal advice.

That aside, you need to find out where the water ingress has come from and if it's old or current. My guess it could be something to do with the roof of the conservatory/porch area, possibly around the flashing. You'll need to hack of all that plaster to expose the brickwork and let it dry out if it is indeed still damp.

The external brickwork does require some repointing using a lime mortar by the looks of it.

stuart45

You probably have got a 9 inch solid wall, which are generally more prone to penetrating damp than cavity walls. The wall looks like it could do with a repoint. The bottom section looks like it has been done, possibly there was a damp issue before, but could have been done with cement mortar instead of lime. The inside plaster would be better done with lime instead of Gypsum.
Water may also be blowing back from that shallow pitched roof onto the brickwork in strong winds.
Another small issue could be the Dish is shading part of the wall. Solid walls rely partly on heat from the sun, and partly from heat inside to keep them dry. Generally a well built solid wall with full internal joints as well as external only gets wet about halfway, although there is only a certain amount of driving rain they can take.

Mickey666

Next time it rains, get out there with an umbrella and have a good look at how all the rainwater goods are behaving.  Check for overflowing gutters, leaking downpipes, how the water flows off those flat roofs, etc.  Also clear away anything that might be preventing good ventilation.

Doozergirl

A surveyor wouldn't normally look for damp on the first floor. 

I suspect your problem is the satellite dish and the fixing allowing water in.  It looks perfectly placed.

Not a hugely expensive fix, but probably made worse if that is the original plaster on the walls.  It was probably blown anyway, but the water has exacerbated it.  

Benjamin2021

Thank you everyone, these are really helpful responses. 
A few Qs: 

• How problematic would it be to leave the brickwork as is (i.e. no repointing) until next Spring? We were going to save up and take down the conservatory then, so it seems sensible to do it all at the same time. (As I assume to do the repointing now with the conservatory there would require scaffolding?) But I don't want the problem to get a lot worse?
• If we did get the repointing done, how much should we expect that to cost (excluding scaffolding)? 
• When Mickey666 says 'clear away anything that might be preventing good ventilation' how do you mean? Do you mean on the inside of the wall avoid putting anything up against it? Or do you mean somehow clearing the external part of the wall? 

Thanks again!

stuart45

You will really need scaffolding even when the conny is down.
Cost depends on where you live, but expect to pay at least £60 per metre for lime pointing.

neilmcl

Benjamin2021 said:

Thank you everyone, these are really helpful responses. 
A few Qs: 

• How problematic would it be to leave the brickwork as is (i.e. no repointing) until next Spring? We were going to save up and take down the conservatory then, so it seems sensible to do it all at the same time. (As I assume to do the repointing now with the conservatory there would require scaffolding?) But I don't want the problem to get a lot worse?
• If we did get the repointing done, how much should we expect that to cost (excluding scaffolding)? 
• When Mickey666 says 'clear away anything that might be preventing good ventilation' how do you mean? Do you mean on the inside of the wall avoid putting anything up against it? Or do you mean somehow clearing the external part of the wall? 

Thanks again!

I would've thought repointing whilst the conservatory is there could be done without scaffolding. I think @Mickey666 is referring to the inside, for example I wouldn't be leaving all those bags up against the wall as you have in the picture above.

dickibobboy

I have little to no idea but, the wall inside looks like it’s a previous issue damp issue and pretty dry that maybe whatever the problem was has potentially gone.

The facia boards and gutters look fairly clean and new. I wonder if the previous owners had a leaking gutter for a good while without realising (or bothered to do anything about it) and finally had them replaced. The look of the pointing on the same wall could also suggest it was dripping down during the heavy periods and soaking the wall. 

I suppose it’s hard to see at the minute due to the warm weather but it’s 100% worth a look out next time it’s raining to double check what’s going on around that area along with the join to the roof just below it. 

dogshome

The brick extension on the adjoining house has a lead flashing strip cut into the brickwork where it joins the house -This is a 'Proper Job', but your conservatory doesn't have this, so I'm afraid the seal between the conservatory roof and wall can only be a bodge where rain water is trapped and soaks through the wall - (See the hump in the back of the roof and the splodge of something  just above it)

It looks like a polycarbonate roof, in which case the roof sheets might slide out if the bottom End Caps are removed, allowing access to the back of the roof so that a properly built box section can be fitted, but higher up so that only the stench pipe has to be fitted through it..