Cavity Tray advice

[BIGbadmarky]

Afternoon All,

I'm not sure if this is the correct place for this question but I'll plough on and hope for the best.

I'm currently drawing up some plans for a rear extension to my property with a single pitch / lean-to roof. My question is; how do I stop up the cavity in the existing wall? The pitch of the roof will meet the external wall above the line of the existing lintel (we're using the existing window opening so we don't to stick a great big steel in there).

I asked our architect but he wasn't sure of the practicalities of it.

Any advice would be appreciated.
Many thanks,
BBM

 

[Swwils]

I could be wrong if it applies but the NHBC standards has a diagram for this on https://nhbc-standards.co.uk/7-roofs/7-2-pitched-roofs/7-2-20-weathering-details/

 

[Notch7]

I asked our architect but he wasn't sure of the practicalities of it

Really?

You chop a row of bricks out and put a cavity tray in.