Penetrating damp/leak and new front guttering

[Beckface]

I live in a solid brick terraced house, 2 up 2 down. This month I've noticed the wallpaper is lifting badly in the same place of both the upstairs bedroom (bottom corner) and the dining room (top corner) - one is above the other, both where the external wall is.

This has never happened before. We have damp course proofing and it's only happening in that one corner, so don't think condensation isn't the issue.

The only thing that has changed this year was our front guttering was replaced. We have a vertical piece of guttering going down the front wall between mine and my neighbour's house. In March this year they had a leak/damp in THEIR front downstairs room where the paint was bubbling (in the corner that meets with ours). The original cast iron guttering was replaced with plastic guttering. It fixed the issue for them.

A few questions:

1) Could the leak back around March have affected our house as well but we're only seeing the effects 8/9 months later? The neighbours have painted walls so perhaps the effect was more immediately visible. (This seems unlikely to me as the wallpaper bubbling appeared end of Nov and has definitely gotten worse over Dec, but wanted to check.)

2) I don't know if the tradesman who replaced the guttering filled in the holes in the brickwork left from where the original guttering was. Could this be the cause of penetrating damp?

3) Obs we'll have to get someone in to look at this, but how do we fix the damage done to the wallpaper? Repapering isn't an option at the moment. Thinking of sealing the wall behind the lifted bits and then sticking them back down. (I can post this elsewhere in the forum if needs be.)

Many thanks

[Firewatcher]

The clues seem to point to the guttering, and if the wall is still damp it would be worth taking a good look at the new guttering to check there are no leaky joints. If you only spotted the paper lifting recently, that could be the cause. It may only be a rubber gasket carelessly fitted, but can go unnoticed and give the problem you seem to have. Unfortunately, the best time to check is when it is raining briskly. The original gutter fixings, even if left unfilled shouldn't allow enough moisture through to the inside wall.
Making good the wallpaper by re-pasting should be all that is necessary once the damp problem is sorted and the wall dried out, no real need to seal it.
Pete

[Mr2021]

agree with firewatcher. wait for a rainy day, and get your binoculars out if need be. I had my gutters replaced a few years ago with seamless gutters. The seal to the downpipe failed in a week and I only noticed it by chance so it could have failed earlier. Looking at the damage, I would say a significant amount of water has caused this, and not just water going in to the holes left from the previous installation.

It's a guessing game but you have to narrow down the possibilities. It could be that when removing the old gutter, and they can be stubborn, a tile was dislodged, or the roof felt was punctured etc...fingers crossed wont be anything serious.

Let the affected area dry out and then paste the area generously,

[wes56]

Hold fire on doing anything with the wallpaper or plaster until you have found and rectified the cause of the damp.
Have you been into the loft and had a look at things?
Post photos at the gutter level of the outside, you can do the camera on a stick trick if you dont have a ladder.
If you can go up a ladder then notice how the water comes off the roof into the gutter. And lift a few tiles/slates in the first & second course to see if the felt is working properly or perished & drooping behind the fascia. Post photos of what you find.