Moisture running down inside walls

[gemshan1]

Hi, 60s bungalow has damp moisture running down one of the bedroom walls, I’ve checked the roof and all sound, just wondering if soffit vents would cure the problem? Any ideas..

 

[Wayners]

Water getting under tiles and running down felt. Then falls short of gutter and runs down wall. Lift bottom 2 rows of tiles had have a look.
It's common thing on my estate with 1960s bungalows.

Felt fitted under existing felt with felt supports added to gutter.
Also fix where water is getting under tiles

 

[gemshan1]

As I said I’ve checked the roof (ex roofer), this is not actually running water as in a leak, it’s more like damp streaks in the emulsion on the top part of wall.

 

[JohnD]

Is this the (only) external wall?

 

[gemshan1]

Is this the (only) external wall?

No, there are other external walls but no problems with them.

 

[Mr Chibs]

Condensation from felt in roof... possibly?

 

[gemshan1]

That’s what I thought, think I’ll give the soffit vents a try.

 

[Mr Chibs]

Have you got any ridge ventilation?

 

[mansea]

I had this same issue in my old bungalow, dripping down the internal walls and sporadic patches and staining on the ceilings. I've never experienced it before and was very worried that it would be expensive and put a downer on moving to my new place! As has been said it will mostly likely be condensation on the underside of the roof felt tracking and trickling down at various points. I fixed my problem very cheaply about £30 by adding a load of lap vents to the felt membrane, resulting in more movement of air up there and it's been condensation free for about a year now...

If you wanted to throw money at the problem you can do loads from soffit vents, ridge vents, fitting new breathable membrane, fitting mechanical vents etc, but I tried the cheapest and easiest DIY option first and it was almost immediately resolved with visible reduction of moisture within a few days, no dripping within a week and completely touch dry within a few weeks to a month...

 

[^woody^]

Photos would help. Water runs down walls differently depending on the cause.