Damp Patch on Parapet Wall

[CHarr]

We recently had an extension built that includes this newly built parapet wall which supports a lean-to conservatory roof.

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• CHarr
• 22 Jan 2014
• 1

There is a large damp patch on the internal face of the wall, so I have so far deferred plastering while I investigate the cause and get it fixed.

Untitled

• CHarr
• 22 Jan 2014
• 1

I originally assumed that the conservatory roof was imperfectly sealed and/or the flashing was suspect, but the glazing company (who have a very high reputation in the area) are adamant that there is nothing wrong there. Instead, they said that water is probably getting into the cavity from the joints in the coping stones, and after soaking the insulation material, the moisture is penetrating the brickwork. They said that the copings should have been bedded on DPC, and that the joints will never be reliable/weatherproof.

Does this sound like the most likely explanation?

 

[kbdiy]

Who contracted the building of the wall? You or the conservatory company? If you, then the conservatory company can blame you/ the builder for the lack of DPC and damp penetration. If it was the conservatory company then they are wholly responsible for the entire structure, even if they subbed out the brickwork.

 

[CHarr]

Who contracted the building of the wall? You or the conservatory company?

Me: so obviously I can't 'just' say "It leaks, fix it!". Would it be normal to put DPC under coping stones on a parapet wall?

 

[skhudy]

looks like it!

 

[stuart45]

They need a tray as well.

 

[kbdiy]

... and a hip iron to stop the whole lot sliding off.

 

[Deluks]

Someone's getting a call back!

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

 

[trowlerman]

its looks like there is no dpc below copeing stones , and why have they built the brickwork that height ?

you cant put a tray in stepped brickwork

 

[NS215]

yes you can, you can put a cascading tray in

 

[NS215]

it looks like something is out of square as the lead is not running parallel to the roof !!!!!!!

 

[stuart45]

you cant put a tray in stepped brickwork

http://www.manthorpe.co.uk/Building/Products/Cavity-Trays/Stepped-Tray-System/Brickwork.html

 

[trowlerman]

ah yes forgot about them plastic jobs, however is their enough brickwork their to put them in ?

whats the reason for putting a stepped flashing in couldn't the brickwork be lower so the lead upstand went straight under the coping ??

 

[s60tsy]

should the lead not be fitted under the copings, if the top brickworkgets wet it could travel to the bricks below surely?

 

[NS215]

Not if a cavity tray is fitted
If that was the case then chimney stacks would be all covered in lead!!

 

[s60tsy]

does the parapet need flashing to the house? and is it?