Help with roofing coping stones gable end

[pghstochaj]

Dear All

I have a gable end which has coping stones and slates. The house is a timber framed house with stone outer leaf. It wasn't built very well so am always fixing the original poor construction issues.

I am getting a leak underneath the coping stones and have a roofer to come and look at this week. He has previously repointed the joint with the slates and coping stones, and the gaps between the coping stones a while back. Water is still getting in. The water drips onto some of the timber frame so I urgently need to sort it, but luckily I can access the area from some eaves to monitor. I am hoping to get some advice on what I should be wanting him to do to improve the design and not just bodge it up hoping that pointing mortar will fix it.

A while back, one of the coping stones got knocked down during tree work so I have a photograph showing the make up under the coping stones. There is a stone wall outer leaf, the slates abut the wall (you can just about make out the line of slates in the photograph I think) and I think the roofing felt is then run up to the outer leaf. This is then covered by a bed of mortar which the coping stones should have sat on.

I suspect that water is getting under the coping stones and then getting through the mortar under the coping stones where it sits on the felt (which has a small hole in it) and then it drips onto the inner wall.

What would people advise to sort this out properly please? I am not a roofer but the things I have read up/thought about include:

- Soakers versus pointing (the pointing never sticks well to the coping stones). Is there anyway to put some soakers in.
- Capping over the coping stones with lead (but noting the lack of a soaker, would this even work.
- Just remove the mortar bed, refit the coping stones on a fresh bed (after repairing the felt) and point the gap between the coping stones (or will this always just fail with time anyway).
- Any product better than mortar for filling the coping stones gap such as a resin (the mortar does not really adhere with the coping stones).
- I have a small scaffold that means I can easily access the first two stones, going beyond those I would need a built scaffolding.

Thanks very much, I very much appreciate any help that somebody can provide.

 

[datarebal]

What your guy has done would Likley divert water where you don't need it.
I can see a soaker with small upstand .
I'd be inclined to take those soakers out make some wider ones that extend over the masonry. And then re bed the copings .

Easy enough .

 

[pghstochaj]

Hi, thanks for the reply. Maybe it’s a terminology issue but where do you see a soaker? I can only see the bed of mortar that the coping stones originally sat on. Thanks

 

[datarebal]

Right here

 

[datarebal]

Imo if you simply cap the copings in lead you could still get an issue . The existing soakers have a very short upstand . (they are there)

 

[pghstochaj]

Thanks both, I can see those in the picture now. What product do you think I should be asking for and should they go all the way to the outer leaf? Should I get the roofer to strip back the mortar, install new soakers and then just re-bed the coping stones? Does anybody have a better solution for filling in the gaps between the coping stones please, I keep finding that the mortar doesn't stick so it quickly allows water in.

Thanks again.

 

[datarebal]

There's no other permanent solution

 

[pghstochaj]

Thanks, but I have not properly understood, what would you suggest is the correct detail for this please?

 

[datarebal]

Remove existing lead soaker . It's upstand is to small .
Replace with a lead soaker wide enough to go under the slate and extend across the parapet .
Do this from top to bottom . Then replace copings .any ties can come from between soakers which will secure the copings.

 

[pghstochaj]

Thanks for your response. Should the lead extend to the outer edge of the coping stone or stop short once it is onto the outer leaf? Do the copings still sit on mortar on top of the lead (I read mortar and lead do not work well together due to lack of adhesion).

Thanks for your help - it will help me with the roofer when he comes tomorrow.

 

[datarebal]

To the outer edge yes for maximum protection .
The lead to mortar will be fine . But use ties as I've suggested .
You will also read about applying bitumen paint .. won't be required here