Capping parapet wall coping stones

[PostHeads123]

Been getting damp on the wall below this, so had new flat roof and existing coping stones rebedded, there is dpc under the coping stones, pic below is work complete. I'm still getting damp though after long / heavy persistent rain, broke through ceiling below looks to come from the parapet wall. Roofer has suggested capping the coping stones in lead, for capping is that the only option or are there other products, may be upvc fake look, or would I just be better off with new / better coping stones ? Im not too bothered what it looks like as the coping stones not too visable from ground level. We are not 100% sure this is the cause of leak so wary of throwing more money at it unless I'm sure that's the issue?



Thanks

Edited by PostHeads123 on Sunday 5th January 01:38

[Aluminati]

Are you 100% those stones were removed and re bedded ?

[PostHeads123]

Aluminati said:

Are you 100% those stones were removed and re bedded ?

I cant be 100% sure they did all of them but they sent me pictures of rebedding some, job was to rebedded them all. Will question them on this.

[Aluminati]

Sorry, that is chronically st.

The dpc should overhang the wall at least 25mm either side, the old bed/joint should be cleaned off, and while I’m typing, his lead work is st as well. And that’s not a bed.

https://www.labcwarranty.co.uk/technical-blog/guid...

Edited by Aluminati on Saturday 4th January 19:26

[CoolHands]

Apart from that, it’s perfect

[PostHeads123]

Aluminati said:

Sorry, that is chronically st.

The dpc should overhang the wall at least 25mm either side, the old bed/joint should be cleaned off, and while I’m typing, his lead work is st as well. And that’s not a bed.

https://www.labcwarranty.co.uk/technical-blog/guid...

Edited by Aluminati on Saturday 4th January 19:26

Thanks for the info and the links. I've had them out a few times to look but they never send the guy who did the work but they have the pics. I guess I'm going have to find another roofer or could a general builder cover this kind of work? The firm who did it were recommended, good reviews but I'm quite far out from there usual patch so probably subbed it out.

[Grobag]

My guess would be it’s rain hitting the brickwork between the top of the flashing and the coping, soaking around the back of the flashing and into the room below. When the copings were done, did you by any chance look down the cavity and see whether there was a cavity tray? There needs to be a DPC across the inner leaf in the same bed joint that the flashing tucks into to prevent it from happening. Might be wrong but the flashing looks like flashband rather than lead?

[Aluminati]

Get a decent builder for the copings. The brickwork underneath looks a bit fragile, so it could escalate.

Alternatively, you could coat the copings in a liquid to give you a cheaper solution.

[PostHeads123]

Aluminati said:

Get a decent builder for the copings. The brickwork underneath looks a bit fragile, so it could escalate.

Alternatively, you could coat the copings in a liquid to give you a cheaper solution.

Thanks, plan is within next 5 years to do full refurb of house and roof but I've been saying that for last 10 years lol. Coating might be option to buy some time. I really went to a big effort to get a recommended roofer, didn't go for cheapest etc thought I found one, but starting to think not. It's stuff like this that puts me off doing a big refurb and may be just moving. Thanks for the help. appreciated.

[PostHeads123]

Grobag said:

My guess would be it’s rain hitting the brickwork between the top of the flashing and the coping, soaking around the back of the flashing and into the room below. When the copings were done, did you by any chance look down the cavity and see whether there was a cavity tray? There needs to be a DPC across the inner leaf in the same bed joint that the flashing tucks into to prevent it from happening. Might be wrong but the flashing looks like flashband rather than lead?

Thanks, no cavity. I broke through ceiling underneath ands it's just two brick deep. Yeah there is a dpc where the lead goes in, it was already there might be clearer in this pick though I can't tell if the lead over it or under it.



This was the roof originally dpc more visible



One of the firms I did have out to quote thought same, rain soaking around back of where flat roof enters the parapet, but originally it didn't even having flashing.

I'm not sure if they used lead or lead flashband, the quote said 'lead flashing'.

Thanks

Edited by PostHeads123 on Saturday 4th January 20:20

[Douglas Quaid]

It looks like lead. Flash and is basically tape so you can tell the difference quote easily. The roofers have guaranteed the job so can’t you call them and get them to come back and sort it?

[wolfracesonic]

A couple of thoughts from afar, the dpc they used should be bedded on mortar, it’s not immediately apparent it is in the pic; is there a drip groove on the underside of the copings where they overhang, ideally there should be to let the water landing on the copings to drip clear of the brickwork rather than tracking back under and soak into the bricks. If you think it’s a solid 9’’ wall the bricks may getting sodden and the water sinks down and it appears internally below, think the opposite of rising damp. Painting the copings and bricks with something like Stormdry masonry cream may help and is not a big job.

[PostHeads123]

Douglas Quaid said:

It looks like lead. Flash and is basically tape so you can tell the difference quote easily. The roofers have guaranteed the job so can’t you call them and get them to come back and sort it?

Yeah guaranteed so will give them a bell, they been out twice since job done, but it's never the guy who did the work. I just wanted to get some other opinions before I talk to them again and then I'm better placed to say what I want doing. Last time they came out they said next thing would to try would be to cap the copping stones, so assuming that is the issue would probably resolve it. I'm not good with heights or I would get up there myself and try a few things.

The lead flash tape they have appeared to have used is that wrong then?

Thanks

Edited by PostHeads123 on Saturday 4th January 21:51

Edited by PostHeads123 on Saturday 4th January 22:55

[PostHeads123]

wolfracesonic said:

A couple of thoughts from afar, the dpc they used should be bedded on mortar, it’s not immediately apparent it is in the pic; is there a drip groove on the underside of the copings where they overhang, ideally there should be to let the water landing on the copings to drip clear of the brickwork rather than tracking back under and soak into the bricks. If you think it’s a solid 9’’ wall the bricks may getting sodden and the water sinks down and it appears internally below, think the opposite of rising damp. Painting the copings and bricks with something like Stormdry masonry cream may help and is not a big job.

No drip grove I could see, I was thinking the bricks getting sodden, they seem quite porous, it only happens after long heavy downpours, a few hours / a night of rain fine, if its a heavy rain for couple of days it appears. I did think of water proofing the brick work, was going to try a few brands on diff part of the house as I read they can change the brickwork color slightly so wanted to find least noticeable brand. I can see the previous owner also might have tried to fix it as the top few rows of bricks on the parapet are slightly different to the rest so looks like they replaced at some point.

Thanks

Edited by PostHeads123 on Saturday 4th January 21:56

[PhilboSE]

I’ve had a couple of parapet walls built in a similar way. First one was exactly like your first picture except it was on a cavity wall and it did at least have a full bed. However it’s crap detail, the coping stones move with the seasons and open up hairline cracks. Then water gets in, it freezes, expands and the mortar blows apart. Then you’ve got a load of water getting past the coping stones and it will find its way wherever it wants to go.

I fixed my issues by lifting the coping stones and laying some lead across the full width with about a 100mm dressing down both sides. Then reset the coping stones on a fresh bed.

That solved the water ingress but I’ve yet to hack off the sand and cement render on the outside face that the water got behind and f*cked.

All because the builder wanted to save £250 on some lead.

[PostHeads123]

PhilboSE said:

I’ve had a couple of parapet walls built in a similar way. First one was exactly like your first picture except it was on a cavity wall and it did at least have a full bed. However it’s crap detail, the coping stones move with the seasons and open up hairline cracks. Then water gets in, it freezes, expands and the mortar blows apart. Then you’ve got a load of water getting past the coping stones and it will find its way wherever it wants to go.

I fixed my issues by lifting the coping stones and laying some lead across the full width with about a 100mm dressing down both sides. Then reset the coping stones on a fresh bed.

That solved the water ingress but I’ve yet to hack off the sand and cement render on the outside face that the water got behind and f*cked.

All because the builder wanted to save £250 on some lead.

Thanks, with the snow and rain last night today it was dripping in. Ive asked the roofer to come over this week, hopefully figure it out.

Does home insurance cover this kind of thing, in terms getting someone out who is expert and can diagnose the issue ?

Edited by PostHeads123 on Sunday 5th January 15:41

[wolfracesonic]

If it’s dripping that doesn’t sound like saturated brickwork tbh, that usually manifests itself as a tide mark on your walls, that gradually spreads.

[wolfracesonic]

If it’s dripping that doesn’t sound like saturated brickwork tbh, that usually manifests itself as a tide mark on your walls, that gradually spreads.

[PostHeads123]

wolfracesonic said:

If it’s dripping that doesn’t sound like saturated brickwork tbh, that usually manifests itself as a tide mark on your walls, that gradually spreads.

When I have cut through the ceiling and stuck a camera in there I noticed under the internal facing bricks of the parapet there is a wooden beam, this appears to be sodden and it possibly rising up the brick from that. The beam seems to run the full length of parapet under the bricks, and bridges across to the ceiling so as wood got wet makes ceiling damp. I think it might have always been doing this even before roof replaced, but I had section of ceiling re done and the plaster board there showing it where as the old ceiling hiding it.



Drips where I cut through,this is internal side



The white stuff up.there is residue from me putting expanding foam up there as crude fix, didn't work so removed it.

To be honest it looks well messed up in there, whatever is happening must of been going on years. Starting to fear I may need to have the parapet wall, taken down and rebuilt



Thanks

Edited by PostHeads123 on Sunday 5th January 16:12

[Douglas Quaid]

PostHeads123 said:

Yeah guaranteed so will give them a bell, they been out twice since job done, but it's never the guy who did the work. I just wanted to get some other opinions before I talk to them again and then I'm better placed to say what I want doing. Last time they came out they said next thing would to try would be to cap the copping stones, so assuming that is the issue would probably resolve it. I'm not good with heights or I would get up there myself and try a few things.

The lead flash tape they have appeared to have used is that wrong then?

Thanks

Edited by PostHeads123 on Saturday 4th January 21:51

Edited by PostHeads123 on Saturday 4th January 22:55

Sorry my phone autocorrected. Flashband is tape. Lead is quite clearly metal, the two look very different so you can tell quite easily. Flashband is not what you want but from your photos they have used lead, maybe not the neatest job but it is the right stuff for the job.