DPC and Cavity Trays - Retrofitting Trays Information, help and advice on many architecture, self build and design problems and issues

[plows]

My new build is coming on and I have used catnic lintels above doors and windows. We have also installed two 5 mtr RSJs .Building control is happy with the work but I got a letter from my insurance company saying can I give them a report confirming that we have fitted cavity trays to all lintels and joists.They are not in the drawings and sections and B/c have never mentioned these only asking if we have ,membranes fitted around windows etc
The RSJ s are suspended across the house sitting on cap stones. they are the lead for the 2nd floor walls neither has a cavity wall under them.They will be boxed in.with plasterboard.My friend who has 20 years experience say he has never fitted one in any project he has worked on and internet sites say they are only required in severe weather areas where brick work could take through rain water.
Will I have to retrofit trays and if so on which sections?
Dave ....................................riding the learning curve

[welsh brickie]

the building control has passed the work, and cavity trays are not stated or needed, then no other work is warranted, the insurance company surveyors are not qualified or experienced to override the building control officers.

[plows]

Hi thanks Ive checked the architects drawings which the insurance company are now asking for and actually the drawings state cavity trays over the lintels. and RSJs . My builder missed them Hes says hes never had to fit them on catnics and joists just adds weep holes. As I said B/C have inspected my nearly finished house and informed me they where happy that no remedial work was needed and that all was good to go onto completion.
I think the insurance company will refuse insurance against damp.and water ingress.
I have one cavity wall 6 mtrs long without trays and one 4 mtrs long also without. Both easy access straight runs.Do you know how much is a fair price if I do need to retro fit.I can negotiate with the builder or hold back a sum to fit them.
This is my first build and its been tough but Im getting there.
Dave E9 london

[welsh brickie]

are they catnic boot lintols? or catnic box lintols, boot lintols are shaped in a way where damp trays are not required,

[plows]

Its probably a box lintel.which means I might have to fit trays above them? did you think about the question of costs to give me an idea how much I need to rectify these defects

[welsh brickie]

I don't know probably £200 to £300