Parapet wall capping stones? Advice Please!

[northcave]

Hello all.

Ok firstly here are some photos of a parapet wall on a coach house I recently bought and some questions. All advice taken seriously as I am about to have internal wall insulation installed and so need to fix asap.

The facts:

1. Water ingress as salts seen in corner below the end of the parapet
2. I lifted a slab and no DPC.
3. Lead only on inner side of wall and undercuts only about an inch.
4. I previous put weather seal paint on top just as an easy fix last November. That's the white stuff. I appreciate i might not do much.
5. It is solid brick as you can see.

The Questions:

1. Is the water really soaking through these stones or is likely to be running off and then through the brickwork?
2. If through the stones then should it remove them all and put a dpc down or lead cap the lot? Ideally I don't want to have to remove them all and pay to have scfolding put up etc. This one stone took enough work to clean the old mortar.
3. Would that Acrypol Paint be a good 'medium term' solution to created a barrier.

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[ree]

Is moisture entering the building? Can you see any disfigurement on the plaster walls or ceiling?

Pics of the very end of the coping run and just below where the staining is occurring (to the left in pic 4) would help.

The lead looks to be fairly recent code 5, which is good. The problem with fixing a full lead DPC directly under the copings is that it would make them unstable

The overhang and throating appear to be adequate. You could run a masonry disc up the outside throating of the last two copings.

You could lightly spray or water test starting at the bottom and slowly working up a few feet. Do it slowly and carefully observe.

Given the age of the building its doubtful that the copings have been sliding down the gable pike but if such movement is suspected then some kind of hip iron can be used.

 

[cannonfoder]

what aout a dry verge system????

 

[northcave]

Is moisture entering the building? Can you see any disfigurement on the plaster walls or ceiling?

Sorry yes I forgot to include this one:

 

[catlad]

Try putting the copping stone back on with lead seal that should seal better than cement, and have you checked the lead soakers.

 

[ree]

Given the amount of cracking at the corner position shown in the pic, then its possible that structural movement has taken place ( or is taking place), and the movement might be the cause of the leaking.
Thermal movement might be the most obvious culprit.

Are any cracks or slight bulges present on the external brickwork?
Are any signs of cracking noticeable in the ground floor rooms?

FWIW: your gutter is holding much debris.

 

[northcave]

Given the amount of cracking at the corner position shown in the pic, then its possible that structural movement has taken place ( or is taking place), and the movement might be the cause of the leaking.
Thermal movement might be the most obvious culprit.

Are any cracks or slight bulges present on the external brickwork?
Are any signs of cracking noticeable in the ground floor rooms?

FWIW: your gutter is holding much debris.

Not really any cracking lower down but there is a slight indication of plaster cracks in the room below where these are. Assume the water is just soaking down.

Considering the last copy stone is flat on the parapet wall, would water sit on it and soak through or is that unlikely to cause this sort of problem?