Cut Rafter tail length or cut hole in cavity closer block?

[kpwwire]

Hi,

Have a block cavity wall extension waiting for roof to go on. Just wondering what the best option is for rafter tails. (sketch attached)

The roof angle means the tails of the rafters will cut through the cavity wall closing block.

Looking at it seems to make sense to me to cut the rafter tail and a little out of the block leaving the cavity closer block acting as a fire break and still enough rafter tail to support the facia and soffit boards.

What do you think the best option is?
Just cut the tail and not the cavity closer block?
Cut both block and tail?
Something else I could do?

 

[^woody^]

You should not close a cavity like that. That's a thermal bridge. Wall insulation should meet the roof insulation. Then the rafter trails don't need cutting

 

[kpwwire]

Thanks woody for your reply. I was aware of thermal bridge, the engineer advised to close the cavity with a block as a fire barrier, so just looking for the best option with the thermal bridge.

 

[^woody^]

Your engineer seems to be behind the times

 

[datarebal]

he is behind the times. a simple birds mouth over the plate insulate up, plumb cut to rafter ends, soffit and fascia on job done . standard stuff

closing the cavity like that will cause issues at sometime.