Damp?

[Tristy]

In our bedroom at a top corner we have damp. The wall is a mix of outside wall one side and adjoining property the other. The ceiling seems dry.

There was dark mould appearing which we thought was ventilation problem as the pvc window doesnt have a vent sash. We get dark mould around the window in the bedroom and living room too, we put this down to the windows, we’ve cleaned this up and seems ok. The rear of the house is ok as the windows have vents.

We cleaned up the wall on Saturday, but this morning we could see a patch on the corner looking wet and it was when you touch it. It hasnt rained last night, but was -3 outside.

Would this be an outside issue like guttering, tiles or condensation? We had a quick look in the attic and couldnt see any leaks..

Many thanks

 

[Notch7]

Do you have damp around the window reveals? -there could be an issue with either thermal bridging or incorrect DPC arrangement. If the plaster touches the external brick skin anywhere, damp can work through porous bricks and into the plaster which is hygroscopic.

If you have severe condensation on the glass, then maybe there is too much moisture in the air in the room.

 

[^woody^]

Black mould is condensation. Yellow or brown stains with a defined edge and no mould is penetrating damp.

 

[Tristy]

Thanks for your replies both.

Notch7, the damp is around the window reveal (if I got the term reveal correct). Its not serious, wipe down with dry cloth and it all comes off. And probably takes a good year for it to come back, but it is very light. I have noticed the sealant outside the window is starting to deteriorate in some areas. I will get ladder for the weekend and re seal around all windows. We assumed this is damp from condensation on the walls as the glass is wet if its cold outside and warm inside. I have found this morning that I can slightly latch the top window opening slightly to allow some air through, this might help?

Woody, this morning on that top corner there is a clear yellowing to the wall with an edge to it, shining a light into the edge of the wall/ceiling (theres no coving) I can see water droplets shimmering.

 

[^woody^]

Water droplets is going to be condensation.

This in itself will cause some very slight staining, but this is different to water penetration staining. The key is that there will be a defined edge with water penetration, and mould will not be growing on it.

 

[Tristy]

Thanks Woody

It hasnt rained the last two days, so I am thinking too its condensation.

Will set up the oil heater by the wall again to dry it and then keep window open and see if it shows again.

 

[Tristy]

Heres a pic of the offending corner:

 

[Doggit]

Oddly enough, that could be water penetration as well as condensation. But it's on the slope of the roof, and you won't have any insulation under there, so cold and condensation is more than likely. Clean it off with a mild bleach solution, and pick a cheap damp meter off of eBay.

 

[^woody^]

pick a cheap damp meter

That's the worst thing to do. Everything will be damp according to the meter. Everything.

Even an expensive meter will show dampness. A meter is useless if the user does not know how to interpret the readings.

 

[Doggit]

Yellow or brown stains with a defined edge and no mould is penetrating damp

No yellow or brown stains on the outer wall, but there does appear to be a defined edge towards the left. If the damp meter doesn't find a defined edge, then that proves condensation, which is what I suspect it is as well.

 

[Tristy]

Thanks both. That defined edge on the outer wall could be staining from the black mould. It was going that far down, and ive wiped it all off.

The patch on the wall at the top near the slope which has black/dark areas which was wet this morning. Its darker as the paint has crackled and the mould is in the paint cracks.

The wall is dry this evening, so will leave window slightly adjar and see in the morning. The outside temp is exactly like last night, so same conditions...