water from stone!!!!

[Rolyan]

We have an old stone built house, circa1900. The gable end appears to be letting the rain through, and the room inside is showing damp. We've had the coping stones repointed on the roof, to stop leaking down, but no joy. Any hints on how to stop it. Could the stones be porous, ad can they be treated to stop it.

 

[AnonymousImport]

whats the condition of the mortar joints like on the gable end do they need re-pointing..

 

[Rolyan]

thanks for your response. Nope - no real problem with the pointing. The top of the gable does get damp, 'cos its very exposed, but still surprised its going through. If its not the pointing, what else could it be (and where do I go from here).

 

[AnonymousImport]

could try some waterseal for brickwork & stonework, has the house had a new roof on just wondered if there is overhang on the tiles over the gable should be about 40-50mm

 

[DAZB]

If it is near the top then it may be the point where the Copings meet the Ridge that needs looking at. If it is at the foot of the copings near the Gutter then it may even be the Guttering or your eaves slates that are the cause. Anywhere in between the two and it may be either that your copings may need treating with a water seal (Thompson's) because Coping stones are usually made from Sandstone and over the years they will perish and admit water or that they need taking off and rebedding so you can make sure the mortar joint between roof and coping is a good one. Common practice nowadays is to have a run of Lead under the Copings starting at the bottom in approx 4 foot lengths running up to the top with a lap on each of at least 6 inches.The lead needs to be about as wide as your Copings and will stop any water that ever did find a way in.The latter is a lot of work and will involve a scaffold of some kind so try it as a last resort.

 

[Rolyan]

Thanks for both the comments above. I've had another look at the gable, and there is a little bit of pointing missing, approximately one stone wide. Could this little bit of missing pointing allow a lot of damp in? On the inside, the damp extends away from the corner (roughly where the pointing is missing), getting less and less, and stops after about 4 feet along the wall.
When its been repointed, is it worth putting Thompsons waterseal on anyway?
Thanks again for the help - much appreciated.

 

[AnonymousImport]

the gable itself may take alot of driving rain thus allowing water to penetrate through so it is worth trying a water seal,however the bit you said will need re-pointing,is the other joints alright or is the mortar starting to crumble & go soft,can you rake it out with a screwdriver if so it will let the damp travel through to inside,also there is a bit of confusion about the copings,i thought being a novice you were reffering to the ridge tiles, dazb seemed to think you had copers running up the verge, which is right does the tiles hang over the gable or is there coping stones up to the ridge...

 

[Rolyan]

We have coping stones running up the edge of the roof, up to the ridge tiles. I've had aother look, and these do overlap by a couple of inches. They have been repointed inbetween each stone, and also along the inside edge running up to the the top.
The pointing doesn't appear too bad, other than the missing bit. The main problem is that the missing pointing is right above a small extension, so theres no way I can get a ladder to it. I may have to get a professional in!!! I want to make sure I know what he needs to be doing, so all the comments above have been most appreciated. You're right, I'm only a novice, but this is a really useful site. Thanks again. When we get a bit of dry weather, I'm going to get the pointing done, and waterseal it as well.

 

[Rolyan]

Having looked even closer, Ive fially noticed (!!!) that one of the coping stones has a piece broken off, where it overhangs. This is about 4-5" wide, and is broken off by the amount overhaging. The gable end is damp directly underneath this, so i guess I've finally found it.
QUESTION - can we just get this bit built up (mortar or whatever) to save time, money and stress! I'm a bit loath to start taking the coping off and replacing it, as i dont want to start creating more problems