On Oct 24, 7:49*pm, "Toffee Monday" wrote:
"David Nebenzahl" wrote in message

s.com...

On 10/24/2008 3:40 PM Aaron Fude spake thus:

My carpenter just told me that if I am having a skylight put in
between two rafters, I should double up each rafter because the hole
in the wall weekens the roof. Do you agree with that?

Yes.

Wrong information, for the question asked.


Normally, the rafters are not doubled up. A typical skylight
requires one rafter to be cut to make a large enough opening, and that
is what is done. Then the opening is boxed in to the right size using
a doubled cross piece the same dimension as the rafter at the top of
the opening and at the bottom that is tied in to the rafters on either
side. That provides sufficient structural integrity. In essence the
cut rafter is still there and carrying load, it's just tied in now
with the skylight framing.