OK, I'll stick my neck out. We've done very few flashings on comp for
the last 18 years or so, using (first) the highest quality polyurethane
caulk we could find. However, for the last 10 years we've been using
Geocell 4500 which states on the tube that it is compatible with
asphalt/comp shingles. For a variety of reasons not related to leaks,
we've had to pull some of these L-feet to which we saw there was a
bond/seal to the shingle like it had been welded to it. The Geocell was
still extremely flexible.
Whenever (infrequently) there's a chance we look for stains
on roof decking and rafters if we're in the attic of an old install. Of
course there is the need to think about what you're doing when your
applying the bead with regard to location and quantity of caulking and
be conscious of torque applied to the lag bolt, being sure you get some
caulking squeezed out the side of the L-foot, covering the head of the
lag bolt with caulk also. Its a bit of an art we take seriously. So far
as we know, no leaks with thousands of L-feet.
Oh, and flashings are good too, but are not perfect.
Bill
Feather River Solar Electric
Bill Battagin, Owner
4291 Nelson St.
Taylorsville, CA 95983
530.284.7849
CA Lic 874049
www.frenergy.net
On 4/21/2021 7:40 AM, Jeremy Coxon wrote:
I’m interested in what the group has to say about the trend, by the
racking manufacturers, away from the use of flashings for asphalt/comp
roofs? We have long used SnapNRack flashings with much success. I
especially like the fact that the penetrations are fully flashed and
do not rely on sealant. I am NOT a fan of their new raised cone/epdm
gasket flashing. There are a number of these raised cone flashings in
the marketplace and it’s my experience that they don’t hold up to the
test of time and I wonder what the roofing manufacturers have to say
about this.
I see that Unirac, SnapNRack and others are now offering basically a
sealed L-Foot which is essentially where we were 15-16yrs ago and met
with a lot of opposition from the roofing industry. Just interested
to hear what you guys are using these days on asphalt shingle roofs
for reliably dry attachments?
Best Regards,
Jeremy Coxon NABCEP # 091308-21
MWBE Certified
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