dg wrote:

A 250mm deep joist 25mm up off the wallplate is [potentially] going to
need a significant chamfer at the ends to stop them protruding throught
the roof. The BCO may well not approve this unless the joist is
strengthend at the bearing or calculated to prove it is OK.

I had 200mm deep joists, and as you suggest needed to chamfer them at
the front of the house where the original pitched roof was to remain.
The BCO seemed ok with that though.

One downside of chamfering though is if you want to add a full depth
dormer later - you will no longer have an easy way to fix the rear wall
of it to the ends of the floor joists without having to fix little
extensions onto each of the joists


--
Cheers,

John.

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