cavity trays

[renner68]

got to the end of my 6mx3m exstension,looks gr8. had the flat warm roof felted and put the lead flashing on myself,expecting the b.c 2moro to sign off but looked at my plans before and didnt realise i need cavity trays putting in. s***. was realy pleased with myself till then. will b.c insist on them. school boy error.

 

[freddiemercurystwin]

Usually, especially if brickwork. You'll have to see what he says.

That said, it begs the question what is the condition of the existing wall? brirck or render, good nik or crappy? Even ignoring the BCO demands (or maybe not) it is often foolhardy to avoid fitting them. The costs and PITA factor to rectify leaks that occur later can often outweigh the PITA factor and costs of fitting in the first place in retrospect.