Damp / Water Ingress Problem?

[newforestcottage]

I have a damp / water ingress issue, which I'd like to understand better, and solve.

We live in an early c.1900 red brick cottage, with uninsulated cavity walls. This is the only room suffering from this problem, on all three external walls.

As you can see in the photo below, there are some obvious water marks around the window, and on random areas along the wall. Not all these patches reach the ground, so whilst I'm sure there is a [slate] DPC breach somewhere on the internal leaf, they don't all appear to come from below. Saying that, they appear no higher than 5/6ft. I suspect it's mostly down to the cavity wall being breached by debris (?) but this seems very high for that too. They are not wet to touch (which I presume rules out condensation). There is some very very minor peeling of paint around the window.

I'm able to run a dehumidifier overnight, in the meantime, which keeps it at bay, but they never fully disappear. This is it, at it's worst.

I am unable to see into the cavity, for obvious reasons, but do intend to extend our hallway (left) with a front porch at "some point in the future", which would allow me to look down there and investigate with more certainty. But until then, I can't.

The floor is a raised timber floor, if that's in any way helpful?

Ultimately, what is the correct thing to do here? Happy to provide more info and/or share more photos. I'd like to better understand potential causes, and how to fix it (obviously there are more costly solutions, and more budget friendly ones, so I'd just like to understand options, and what the journey is to get from "this" to solved).

Needless to say, it is worse at this time of year, and not a problem at all during the summer.

investigate more

 

[Wayners]

I you sure its a cavity wall? Unlikely with that age of property.

 

[newforestcottage]

Yes, certain. We’ve done structural work on other parts of the house, and it’s cavity wall. Early cavity wall.

 

[newforestcottage]

I’m not adverse to getting into that cavity, if required. I’m wondering if removing the window might help (not that I’ve done that before) as it’ll be a very central location from which to remove any rubble?

 

[23vc]

What’s the outside wall(s) like in terms of how well protected/pointed, any leaking gutters/downpipes etc. Photos will help

 

[newforestcottage]

Gutters are fine. No downpipes. I’ll add some photos of the external wall …

 

[newforestcottage]

You can see some of the pointing has been affected by metal planting ties, which the previous owner put in. I’ll remove these and fill the holes, but even then, that shouldn’t be enough to breach the cavity to this extent, should it?

 

[noseall]

You can see some of the pointing has been affected by metal planting ties, which the previous owner put in. I’ll remove these and fill the holes, but even then, that shouldn’t be enough to breach the cavity to this extent, should it?

The brickwork looks in good nick for the age and seems to be well maintained. I'm wondering if it could be a tie iron issue? Or perhaps a hygroscopic issue? I hate damp problems because they are rarely obvious. Is it a rainy day thing? Is it a low temperature outside thing? Year round thing?