Help with damp in lean-to

[jondas]

Hello all – I hope you can help, and sorry for the essay!

I have some damp issues in a half-brick thick lean-to. I think it is a combination of condensation and some penetrative damp and would like your opinions on what I think are possible solutions – I’m no expert by the way.

Firstly, the condensation. Within a month of moving into my new house I noticed black mould growth in the corners of the lean-to. To tackle this I turned up the heating in the room slightly and locked the windows in a slightly open position to improve temperature and airflow. So far, this has appeared to mitigate things somewhat – but does anyone think perhaps installing some airbricks, maybe high up, would be a better long term solution than having the windows permanently open?

Secondly, possible penetrative damp. On the wall of the lean-to that faces the garden, paint and plaster has blistered and fallen off along the length of the wall at around 50cm high – almost like a tide-mark (with some mould growth as well). I do not believe that this has been caused by condensation alone. This is because the garden patio, which runs right up to the lean-to wall, is a higher level than the floor in the lean-to (which also has some damp patches near the wall). I think that this is the primary source of the damp issues on this wall. Rather than some sort of DPC, I thought that digging a French drain around the external walls of the lean-to, thus preventing water lapping up against this wall, would reduce most of the damp in this wall – does anyone agree/disagree?

I can upload photos if anyone feels this is necessary

Huge thanks to anyone’s input – as I said above I am no expert but I have done some research.

John

 

[^woody^]

If you have penetrating damp, which on a 1/2 brick wall is likely, then this will either be contributing to, or causing condensation dampness too.

So you need to sort out any penetrating damp first - or rising damp if that is occuring too

There are lots of threads on here about how to go about it. But essentially you need to keep any ground well away from the wall, and prevent water splashing up the wall externally to stop penetrating damp. Dry-lining/insulating internally will cure condensation and hide penetrating/rising damp

 

[jondas]

If you have penetrating damp, which on a 1/2 brick wall is likely, then this will either be contributing to, or causing condensation dampness too.

So you need to sort out any penetrating damp first - or rising damp if that is occuring too

There are lots of threads on here about how to go about it. But essentially you need to keep any ground well away from the wall, and prevent water splashing up the wall externally to stop penetrating damp. Dry-lining/insulating internally will cure condensation and hide penetrating/rising damp

Thanks for your quick reply.