Is this a roof leaking, guttering or condensation?

plodder73

Hi hope one of the regular builder types can advise. I have lived in my stone cottage for about 6 years, it has walls about 2ft thick and a stone slate roof. About three weeks ago I had a a lot of rain at the back of the house and my house deveoped a leak above the rear window. I had a steady drip of rain from the wood panel at the top of the window. I thought that might be something to do with the roof and guttering so I had a local builder round who after inspection that it all seemed ok and that I might not get the same problem for another 6 years. He said that these things happen in old houses.

I left it and now today its chucked down again, no rain upstairs but a massive damp patch has appeared downstairs about 6ft from the floor in a couple of places. This seemed to appear very quickly and coincided with me putting the heating on. Does this sound to you like condensation? How do I stop it? It has never appeared before so guessing something has happened. Should I call a roofer, builder, damp specialist? Thanks in advance

iamcornholio

Damp soon after rain, and damp in a defined patch, is not going to be condensation, and will be penetrating dampness

Damp patches near the roof will more likely be a roof or gutter issue. damp patches in walls downstairs will generally be a wall issue.

Roofers (who are experienced) can normally find roof leaks no problem. Builders however, may be less adept at finding leaks, unless they are very experienced in this area and more importantly can be bothered to investigate.

There is no harm in getting people around for an initial view and quote to see if there is anything obvious. But for causes less likely, a professional opinion from a person who wont be involved in any remedial work would be better

plodder73

Thanks very much for that reply I have just investigated the damp downstairs. The wall outside is painted with masonary paint and I started to chip away at it and found that sections of it had come away from the wall and when I scraped it off a thin layer of stone wall came off with it. It revealed that the wall is soaking wet and the paint is obviously not doing any good, in fact i think it may be hindering the wall drying out once wet. So i think I shall knock off all the loose paint and stone and either repaint or get it all sand blasted and repointed.

BlueC

plodder73 wrote: »

Thanks very much for that reply I have just investigated the damp downstairs. The wall outside is painted with masonary paint and I started to chip away at it and found that sections of it had come away from the wall and when I scraped it off a thin layer of stone wall came off with it. It revealed that the wall is soaking wet and the paint is obviously not doing any good, in fact i think it may be hindering the wall drying out once wet. So i think I shall knock off all the loose paint and stone and either repaint or get it all sand blasted and repointed.

I'd be suspicious that the wall may have been painted over to disguise a known damp problem, rather than resolve it.

Is it possible to determine why the wall is so wet on the outside? Typically walls don't attract too much rain unless they are facing the prevailing wind or at a funny angle... is there any leaking guttering or anything that is dripping down the exterior of the wall and making it so wet?

Depends what the type of bricks are, but if the faces of the bricks are shot then water will penetrate more easily, which may be the reason why it was painted over. I'd still look carefully for the source of the water though... or it could just be rain. If you take the paint off and the wall is coming with it then the wall will need re-sealing (cheap), or the bricks replacing (expensive).

(PS isn't it depressing having the heating on in June!)

plodder73

Thanks Blue C its not actually brick but 2 ft thick stone, I have considered sandblasting repointing and siliconing(thompsons water seal or similar) but have heard that silicone isnt ideal because it doesnt let the wall breathe. And yes it is depressing putting the heating on.

iamcornholio

plodder73 wrote: »

have heard that silicone isnt ideal because it doesnt let the wall breathe.

You heard wrong. Wall water repellent treatments do let the wall breath.

Thomsons works well but is quickly broken down, and so only lasts a few years before needing recoating

There are longer lasting silane and siloxane based products which work and last well.

But before any recoating, you need to be sure that porous stone or joints is the actual problem, and not some other defect letting water in