I have an odd repair I need to make, and wish to put some membrane
in-between the lower- and upper-sheets of metal roofing at a lap joint.
Ideally I'd get some more of the same type metal roofing, cut it into
3' sections, and slide it up under the upper piece, and over the lower
piece. I'm deeming this too expensive and labor intensive (a lot of
cutting), and don't like my chances of finding exactly the same
brand/type/shape of metal roof panel.
The dorks that built the roof on my garage didn't lap the panels very
much (I think) and didn't use butyl tape on the lap joint, so all
across the roof there is a 65' long leaky joint. In some places the
plywood sheathing is rotted a bit and won't hold a screw, so I can't
just pull the screws, add the tape, and install new screws.
I'm not going to strip the roof to replace a tiny amount of rot, and
need a way to essentially seal the joint, and to seal all the screw
holes all the way across. I'd just leave the screws that won't hold out
(and fill the holes with roofing spooge, and put screws nearby where
they would hold) if I thought I could really plug the holes, but I
think that would leak given the shearing motion of the panels as they
I'm also tempted to just run the butyl tape above the screw holes, and
at the screw holes, and run new screws above and below the holes that
won't hold a screw. Just leave the holes that won't hold a screw empty,
and let the tape fill 'em.
I think that sliding new metal sheets in is the best fix, and slipping
some membrane in is the 2nd best.