Fix for low cavity trays

[csanders]

Hello,

On one side of our extension roof our builders put the cavity trays in too low and tried to dress the lead down on to the tiles. The cavity trays are above the roof line but the flashing is a mess and there are patches with just scratch coat of render. I posted about this in another thread. I think the BCO has suggested the builders could remove the current render bell, cut the lead off the trays, insert new flashing higher up the wall to get the 150mm upstand specified, and then put the render back on.

Does this sound like a reasonable fix, or should the cavity trays just be removed and put in at the correct level?

 

[noseall]

Hello,

On one side of our extension roof our builders put the cavity trays in too low and tried to dress the lead down on to the tiles. The cavity trays are above the roof line but the flashing is a mess and there are patches with just scratch coat of render. I posted about this in another thread. I think the BCO has suggested the builders could remove the current render bell, cut the lead off the trays, insert new flashing higher up the wall to get the 150mm upstand specified, and then put the render back on.

Does this sound like a reasonable fix, or should the cavity trays just be removed and put in at the correct level?

Give the render a coat of weather seal and forget.

 

[ree]

Poster #2,
That is wrong advice that could make things worse - technically & expensively worse for the OP.

 

[ree]

OP,
Its difficult to see your cavity trays clearly - however, they look very untidy - always a bad sign - & the large piece of whatever at the bottom just appears to be flapping about?
Type X Remedial cavity trays should have been used - maybe they were but its difficult to say?
The cav trays in the pic appear to have been improperly installed - they dont seem to overlap correctly?

What you say a BCO advised is difficult to understand. Neither is splashing so called "weather seal" about.

Do you have damp problems in the extension below?

 

[csanders]

Thanks for the replies. I think the cavity trays will probably be doing their job where they are but I wasn't happy about the exposed render, the lack of lead upstand (which is about 40 or 50mm in places) and the gaps between the flashing. This is a new extension and there are no damp issues at the moment. The other side of the roof is a lot better with 150mm upstand and the trays look more or less the right height. The BCO has suggested cutting a chase above the cavity trays and then inserting lead to get a continuous flashing that will be dressed down over the trays and meet the lead soakers. I guess the upstand would then need to be more like 180mm so the cavity trays aren't damaged by any cutting. The builder has offered to either replace them or cover them as BCO has suggested, but obviously one is much less work.