[RE-wrenches] Flashing vs Sealant... again (is sealant code defensible?)

[August Goers]

Hi Troy,



There has been an ongoing debate on the RE-Wrenches list on this issue for
years now. I've personally serviced many old L-feet systems that are fine
and some that are leaking. The leaks normally occur in the missed holes
adjacent to the L-foot. Also, many installers were using Sikaflex which
over time loses its adhesion to comp shingles. Sloppy work is the worst
culprit.



We've used all sorts of flashings over the years and primarily stick with
Quickmount E-series these days. All holes, both hits and misses, are
squirted with M-1 sealant (from Chemlink) and we slide aluminum flashing
(standard rolls of aluminum cut to size in the field) under the shingles
for the missed holes.



We've never had a leak with a properly flashed system and I am a strong
proponent for using flashing products for all mounting points.



Best,



August



Luminalt



*From:* re-wrenches-bounces at lists.re-wrenches.org [mailto:
re-wrenches-bounces at lists.re-wrenches.org] *On Behalf Of *Troy Harvey
*Sent:* Friday, April 11, 2014 12:20 PM
*To:* RE-wrenches
*Subject:* [RE-wrenches] Flashing vs Sealant... again (is sealant code
defensible?)



1. I'm interest in a poll of installers who are using flashings vs sealant.
Now that the flashing market has evolved, what are you using today? When
did you switch to flashings (if you did). And why not, if you still prefer
sealant.



2. Is there a any code defense for sealant systems ? (L-foot sealed down to
shingles). Does anyone know of a scientific shootout between sealants and
flashings?



Here is my view: The construction industry is slow to evolve. Sealants,
clauks & adhesives are not trusted in general, due to the legacy of code,
and we have a mechanical vs. chemical industry bias.



There is something about seeing a flashing that says, that is a
"professional job", it must comply with code. And yet, my experience says
I'd trust a 50-year silicone over a flashing that depends on gravity.
Gravity should be dependable right? But anyone in snow country can tell you
in spring, water can go uphill after ice dams form. There are high-rise
buildings that use "structural glazing" which is just glass and silicone.
These systems are now getting to be 50 years old without issue.



The cost of flashings have come down in the last few years, but so has the
cost per watt of installs. With 50 feet in a typical install around here
that is $150 in feet, lags & silicone. Or $1500 in flashings, and extra
labor. That can be a large part of a bid, and make you more expensive in a
competitive landscape. That is fine, if it adds value... but I personally
don't see the *proven* value, other than the "appearance" of code
defensibility. Anybody have proof?



thanks,

Troy Harvey
---------------------
Principal Engineer
Heliocentric
801-453-9434
taharvey at heliocentric.org
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