Travis Jordan wrote:
wrote:
A lot of folks who should know don't think the
roofing felt adds much to the water resistance of the roof system.
(Ref Joe Barta & Building Science Corporation)
Unless of course the roof covering is tile, in which case the
underlayment IS the primary water barrier.
And, I should add -- one very good reason for having a semi-permeable or
impermeable moisture barrier between the roof covering (ie: shingles)
and the sheathing is to prevent any condensation that forms on the back
of the shingles from dripping onto the sheathing. And I think all
current shingle manufacturers require an underlayment layer, as do many
state and local codes.