I'm having a roofer redo my metal roof with standing seam.
It is 3 in 12 pitch and located in northeast with lots of snow.
I recently refinished the attic into heated living space.
Rafters are 2x8 on 16" between which I put styrofoam
ridge vents and then 6" fiberglass, then drywall. Probably
not enough but I didn't want to lose any headroom. There
is of course some heat loss and occasional problem with
I'm going to ask the roofer to restrap the roof to leave
3/4" or 1.5" of air space between the plywood and the
metal. Probably this could be vertical strapping of
1x4 open at the lower edge and with a ridge vent at
the top. From the inside out, it will be 1/2" drywall,
6" fiberglass, styro vents, 1/2" plywood, 30 tar paper,
3/4" air space, metal. I'm told it will keep roof colder
and help prevent ice dams. However I don't want the metal
roof to bend under weight or if I stand on it. I would also
like to add more foam insulation on top of the plywood under
the metal roof but since I already put venting underneath,
I think it would be counter productive.
The other question I have is regarding the width of the
drip edge. I would like to extend the overhang a bit without
adding to rafters because rain blows onto the siding a lot.
This could be done simply by changing the fascia to be
3" wide (instead of 1.5" as it is now) and extending the
drip edge out 3". Is 3" too wide for a metal drip edge?
I want to make sure it is rigid enough so that it won't
be bent by ice or by leaning a ladder against it.