cavity wall finishing at ridge

[diydad888]

Sorry, this question maybe roofing as much as wall. building a couple of lean to single storey extensions. I need some help on how to finish a traditional constructed cavity wall (100mm cavity) at the top,
should the cavity wall be sealed with slates or such?
on another point..
my builder has left the sarking on the roof 300mm short of the verges each side, is that normal practise ?
He said it is to prevent the sarking board getting damp in future and he proposes th bridge the gap of 300mm with slate or tiles.
My cavity wall is 300mm, so the sarking finishes just at the inside of the inner wall.
I thought the sarking and roof membrane etc should go over the complete roof area..
Any help will be appreciated,,they begin work again tomorrow,

 

[Alastairreid]

closing the cavities comes under part b fire regs http://www.planningportal.gov.uk/buildingregulations/approveddocuments/partb/

Not a good idea to bridge the cavity with masonry/slate as this can cause cold bridging.

 

[diydad888]

Thanks Alistair,

I meant to say VERGE not ridge...the builders have stopped the sarking 300mm short of each verge, they propose to fill the gap with slate bedded on mortar then extend the battens over this area...is this mental or normal.
the builders are foreign, thanks to a close friend who recomended. so I am not always sure they know the scottish/UK standard methods.

Thanks

 

[noseall]

Gables are usually left open with the insulation brought right to the top.
In fact at the eaves detail it is encouraged to allow the cavity batts to continue to meet the loft insulation forming a seamless barrier.

Internal door and window jambs are usually stopped with cav' closers.

Roofing battens as with the felt are extended all the way to the cloak, being kept short of the edge by only 20-30mm.

However if you are using the dry verge system the battens are kept flush with the edge of the cloak.

 

[Alastairreid]

I meant to say VERGE not ridge...the builders have stopped the sarking 300mm short of each verge.

This is quite normal and good practice.
as stated full fill cavity and felt to edge of verge battens to suit verge detail.