Water ingress, possible penetrating damp?

[McKendrigo]

Hello,

I wonder if anyone can help advise me about what the likely cause of my problem is and suggest some next steps.

During a recent night of strong wind and rain, I noticed a small damp patch in the corner of our bedroom. A small damp area in the about the size of a £2 coin, with a few trails beneath it where water had run down.

I went into the loft above expecting to find a leak in the roof, but I’ve found absolutely nothing in the area above it. No leaks from the roof, no damp patches in the ceiling, no signs of water ingress. The dampness also didn’t seem to reappear on days when it was pouring rain, though tonight there is a slight sign of dampness and it’s raining with 50mph gusts of wind.

This is making me suspect that the water is actually wind-driven rain. The wall is the gable end facing west, in the direction of the prevailing wind. Seems that wind is a factor, as on days with heavy rain the dampness doesn't necessarily appear.

The house is a 1970s detached house. The walls are (to quote the home report) “traditional brick cavity construction with a synthetic stone and render cladding”. There is also cavity wall insulation installed by the previous owners (grey polystyrene bead type).

I’ve had a look at the wall and didn’t see any glaringly obvious problems from ground level like cracked or missing chunks of rendering. I'm also not seeing any evidence of dampness anywhere else in the building, just that one spot.

Mainly looking for some suggestions of what to look at next, or what sort of tradesperson is best to speak to.

Thanks!

 

[JohnD]

Photos please

 

[McKendrigo]

Hi,

Here's a photo of the wet patch from in the bedroom. The wall on the right is the gable end (plaster over brickwork), the wall section above the cupboard door is plasterboard.

This is the loft directly above the corner of the bedroom, with the insulation rolled up.

Here's a view of the small gap between the brickwork and the horizontal beam.

Here's a view of the roof.

Finally, here's a couple of views of the gable end.

 

[McKendrigo]

Just to add to that:

- I did not see or feel any dampness or water on the insulation, beams, roof tiles or wall above/near the leak.

- In the second to last photo there looks like a possible crack running along the underside of the soffit. Unfortunately I haven't been able to get high enough on a ladder to see it more closely. Not sure if this is a possible candidate for the problem, but it looks like it's in the right sort of area at least.

 

[JohnD]

In your second pic, the rafter against the wall looks very dark, as if it is wet.

In your third pic the plasterboard ceiling against the gable wall looks wet and mouldy.

I think you have a roof leak at the gable wall end.

If the rafter is wet all the way to the top, the leak is at the top (ridge) because water runs downhill

 

[Sonic70]

I think it could just be condensation from this cold weather, that corner could be a cold spot. That end rafter it's not clear in the picture if its wet or not, a better picture would help.

 

[Harry Bloomfield]

The wall is the gable end facing west, in the direction of the prevailing wind.

If the time on the photos is correct, then the one outside, taken at 8:44pm suggests the cable is east facing. East facing, means the rain will be blown from the right, to the left, or in other words towards the edge of the roof...

In the photo, I can see what I think is moss growing out from under the bottom tile edge cap thingy (what are they called?), on the left edge. I wonder if the moss might be encouraging rain to pass under the 'cap thing', and to drain down the inside of the wall?

 

[McKendrigo]

If the time on the photos is correct, then the one outside, taken at 8:44pm suggests the cable is east facing. East facing, means the rain will be blown from the right, to the left, or in other words towards the edge of the roof...

In the photo, I can see what I think is moss growing out from under the bottom tile edge cap thingy (what are they called?), on the left edge. I wonder if the moss might be encouraging rain to pass under the 'cap thing', and to drain down the inside of the wall?

The time on the photos isn't correct - 8:44pm I edited them, but I took it earlier in the day. The gable end is definitely west facing.

I hadn't thought of water getting possibly under the end caps in that way though. Obviously wind does sometimes blow from the east, so it's possible. Thanks for the suggestion.

 

[McKendrigo]

In your second pic, the rafter against the wall looks very dark, as if it is wet.

In your third pic the plasterboard ceiling against the gable wall looks wet and mouldy.

I think you have a roof leak at the gable wall end.

If the rafter is wet all the way to the top, the leak is at the top (ridge) because water runs downhill

You are right that rafter is darker than the others, but I think it looks darker than it really is in that photo. I took another photo (below) with a bit better lighting, which I think looks more accurate.

The rafter has never felt wet at all at any point, and if it was so wet the water had turned it completely dark I'd have expected to see some water on the plasterboard and insulation underneath, so I am not sure the problem is caused by water running all the way down that rafter.

 

[McKendrigo]

I think it could just be condensation from this cold weather, that corner could be a cold spot. That end rafter it's not clear in the picture if its wet or not, a better picture would help.

I had another look tonight, and I think in the corner I could maybe see some plasterboard that had blistered as if it had been wet (though it was dry to the touch). I've marked that with a red arrow on the photo below.

That corner is a cold spot though, there's a cold draft there, coming from the gap between the rafter and the wall (the dark gap above and to the right of the arrow).

To be honest, I think you could be right. The big drip of water happened during the recent cold spell in December, and while the area has been damp on and off since, the water hasn't dripped down the wall like that again even in heavy rain.

Supposing that was the problem, is there a something I could try to sort it? My first thought was to shove some rockwool or squirt some expanding foam into the space where the cold draft is coming from, but I am wary of possibly just shifting the problem further down the wall!

 

[Sonic70]

It looks pretty dry there. No Insulation in that gap is going to make it pretty cold.

 

[McKendrigo]

It looks pretty dry there. No Insulation in that gap is going to make it pretty cold.

What could I do to insulate that cold spot? Could I place some e.g. rockwool along the top of the exposed plasterboard that's between the joist and the wall? Should I block off that air gap at all, or should it be left open to let air circulate?

 

[Sonic70]

I would put some insulation on top of plasterboard myself, I dont think it would cause a problem but I dont know for sure, maybe someone else can confirm it's ok for sure.

 

[Coopa]

Hi there. In your roof photo Is it me or is there a small triangular hole on the third tile up gable from gutter , if so ,that probably would cause ,from water coming in , the wet damp mouldy looking patch at the foot of the rafter in photo 0599 where it meets the hardboard membrane , which also looks stained in that patch All depends if that’s a hole though

 

[Koolpc]

Def looks like condensation to me. Had same myself, years ago. I put insulation in the gap between the wall and timber. Worked a treat. No more warm air hitting a very cold spot and condensing.