I realize that 30 is pushing it even with 1" roof
decking. 24" is more common in these parts
(Vermont). I am using 3x6 rafters which are
beefier than normal and putting in some 30"
wide skylights. That's why I wanted to go with
the rafters on 30" to keep the spacing even
because it will be visible from inside. But I
guess I should go with 24-26" rafter spacing
and just frame in around the wide skylights
with extra rafters to the headers as is
usually done. I am not using plywood
anywhere. Thanks,


If you're using real 3xN rafters, you shouldn't
need to double up on the rafters flanking the
skylights. The problem isn't the ability of the
rafters to hold up the weight of the roof, it's
the ability of the roof-decking to span 30"
with the weight of one man plus tools without
flexing so much that it damages things.