Both semis have new roofs, its still soaking! Help please

[ju1iet]

We bought our house in 2018 and there was a wet patch on the internal wall, below the highest point of the roof on the join of two semis.
Now we had the back of the house extended a few years back and had a brand new roof on the back, 2020, followed by replacing the front roof 2022 to try and resolve this issue.
Next door claimed it was our fault, we wanted to try and resolve the issue, no roofers have been able to find a reason in the first place.

With now the whole roof replaced, water is still coming in. Next door sold and the new owner replaced his side, hoping to resolve the issue.
Even after replacing his side, were still in the same position.

I dont know what else to do. Our lift is boarded and my husband can't even see any wet inside to what could be causing it. Next door is the same.

Builder who did our roof, suggests not his issue, although after they did our roof, I found the building company got rid if the roofers who did our side, as weren't happy with them.

If any of you have any suggestions I'd be so grateful. I don't know what step to take.it feels like it'll never end.
Picture is of our interenal adjoining wall with next door. Next door is a lot small patch than ours.

 

[blup]

Have you got before and after pics of the roof(s) externally.

Blup

 

[ju1iet]

Here are some pictures we've had from an independent roofer. He suggested our roofers have gone over the top of the original bitumen. Although we can't see any this in the attic. Our roof has the green membrane. We're the right hand side as you look at the houses.

The only pictures I have of the roof before and after are from the ground. I haven't been up there sorry.

Here's also the last report from an independent roofer. Sorry I don't know what else to do with the situation.

Added the before and afters of the rear roof. The close ups are from the front. We extended the rear of the property and replaced the flat roof with double pitch.
---

We sent an independent roofer down to inspect the work from our roofer and to ensure the connection to your roof was seamless.

Upon removing a section of the tiles on both side to the first rafter it became apparent that Jason's side of the roof has been fitted correctly. However, on your side of the roof, your contractor has not stripped the original bituminous layer and placed a new felt layer straight on top. This is creating 'sweating' between the two layers and thus heavy amounts of condensation.

This condensation is what has been getting into the houses at the party wall on both sides.

Our contractor at the expense of my client removed the layer of bitumen up to the first rafter and sealed both sides. We cannot guarantee that this will solve the issue on your side, but hopefully as it away from the party wall it should help.

Attached are photos of the roof.

 

[blup]

It may be that the wall has residual damp and needs time to fully dry out, maybe even chopping the plaster out to let the wall breathe and speed up the drying process. If there is a continuing source of damp or moisture ingress, that needs identifying, I would start with looking in the loft under the boarding, maybe there's the remains of an old flue. Out of interest did the independent roofer say what the other causes might be when he said he couldn't guarantee the remedy would work?

This guy has posted on here and has a real specialism in damp, he may be able to offer some initial advice:

https://www.maloneassociatesltd.co.uk/

Blup

 

[Owen74]

Are there any pics inside the loft, above that damp wall? Trying to understand what part of the roof is above that wet patch. Is that V-shaped adjoining roof valley ending above it? Could there be condensation dripping down the underside of the that roof valley?

 

[Notch7]

Whereabouts is the wet patch in relation to the roof externally?

 

[Notch7]

Just a question for any pro roofers: is it normal to fit a bonding gutter if the roof material is the same on both houses - I though there was no need at the party wall.

it’s just that these images show a flat type one

 

[^woody^]

Just a question for any pro roofers: is it normal to fit a bonding gutter if the roof material is the same on both houses - I though there was no need at the party wall.

it’s just that these images show a flat type one

No, one is not required. But for some reason it looks like some of the slate battens don't align, so a whilst a bonding gutter deals with that there is no reason why the battens should not align!

 

[^woody^]

Long posts, but what bit of the roof is above the damp?

 

[catlad]

I think the bonding gutter has been removed once both roofs have had new tiles.
I can't see where any water that gets on the membrane will drain to in those images.
Does the wet patch disappear in the summer months?

 

[blup]

We bought our house in 2018 and there was a wet patch on the internal wall, below the highest point of the roof on the join of two semis.

Long posts, but what bit of the roof is above the damp?

 

[^woody^]

We bought our house in 2018 and there was a wet patch on the internal wall, below the highest point of the roof on the join of two semis.

So the water is dripping vertically down from the ridge, not running down the slope or the rafters, just vertically in the middle of the house?

 

[ju1iet]

So the water is dripping vertically down from the ridge, not running down the slope or the rafters, just vertically in the middle of the house?

Yes it seems like it's just in the middle of the house. When the loft was boarded we could not see any damp or wet patches at all.

The water is coming in on the internal wall adjoining next doors. It seems yo be pretty much in line with the ridge.

 

[ju1iet]

It looks like there was no secret gutter on the rear of the roof between the properties so they're going to add one in hoping to resolve the issue.