Coping Stones on Parapet

Bigwelsh · 16 May 2013

I have recently had some work done on my roof (Victorian mid terrace property) and the roofer advised that work is required on the copping stones as they are very porous and may result in leaks in the future. They advise that the coping stones (on the parapet walls) are treated with G4 sealer and then coated with GRP. The cost I have been quoted is £400. First of all – is this reasonable? and secondly – does anyone have any experience of using G4 sealer and GRP? Is this a good solution to the problem?

I would be grateful for any feedback on this.

Thanks

Xenon · 16 May 2013

The only work required on copings should be pointing to the joints. There should also be a DPC under them.

smashngrab · 17 May 2013

It seems all i have been doing for weeks is re-bedding copings using a sbr mix. One thing you dont do is put a dpc under coping stones. If any water ever gets through a coping join or on the edge, it runs down the plastic and tracks underneth the dpc then its in.It also sweats causing dampness on the bottom side.
I know this for a fact as i'm removing them (dpc's) all the time.

New 14" copings is the way to go.

dilly · 17 May 2013

Yes coping stones are porous and this gets worse with age.The soloution offered to you will keep the water from getting in via copings,the g4 is a primer used in fibreglass when fibreglass is applied to concrete.As for costs
On your roof it's impossible to give a idea on

Xenon · 18 May 2013

smashngrab said:
It seems all i have been doing for weeks is re-bedding copings using a sbr mix. One thing you dont do is put a dpc under coping stones. If any water ever gets through a coping join or on the edge, it runs down the plastic and tracks underneth the dpc then its in.It also sweats causing dampness on the bottom side.
I know this for a fact as i'm removing them (dpc's) all the time.

New 14" copings is the way to go.

Cobblers

https://environment7.uwe.ac.uk/resources/constructionsample/Conweb/walls/cavity/section11.htm

smashngrab · 18 May 2013

I'm not talking about modern buildings with cavity's Xenon nor is the original post. "I have recently had some work done on my roof (Victorian mid terrace property." Around here thats mostly 9" solid walls, thats where I'm finding the probs with it.

Pol_Briz · 19 May 2020

smashngrab said:
I'm not talking about modern buildings with cavity's Xenon nor is the original post. "I have recently had some work done on my roof (Victorian mid terrace property." Around here thats mostly 9" solid walls, thats where I'm finding the probs with it.

Hi Smashngrab, I really hope you're still on here! I have a Victorian terrace in Bristol and have my roofer recommending I have a DPC in my parapet wall and new coping stones and I've been reading about how these old houses need to breathe so am thinking if anything I want the existing concrete render removed from the parapet. Do you still recommend refusing a DPC? And what's an sbr mix? Thanks

datarebal · 19 May 2020

D P C = damp proof course, Slate, Lead, Bitumen, plastic

There is more than one choice

Pol_Briz · 19 May 2020

Thanks but that's not what I asked. I'm familiar with DPC and from what I've read it's inappropriate for older properties which should be allowed to breathe through the bricks to let moisture out naturally, yet people keep pushing them and they end up causing more problems.

datarebal · 19 May 2020

if you are familiar then you will know in this situation it will stop the moisture entering the brickwork , solid or cavity
using a plastic course is not a great deal of use. As you are familiar with dpc you know why its of little use.

read more

Pol_Briz · 20 May 2020

I have read around the subject but there is obviously conflicting advice since some people want to sell their products. I'm just a worried homeowner hoping to speak to the person who posted from Bristol saying they had been removing DPCs from parapets in the area.

datarebal · 20 May 2020

Probably a plastic dpc, these have uses but not in a parapet with copings.
The coping is a dpc its self to a point. But not long term reliable .
I would side here with Xenon

^woody^ · 20 May 2020

Deleted.

God damn reviving a seven year old post.

diynot

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Coping Stones on Parapet

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