It definitely depends on the flashing. The Oatey type with the rubber
gasket die after several years, and leak.
For our installations, it really depends on the roof. In some cases
with metal roofs, a flashing can't really have the overlap needed, and
so it just becomes a big gooed on L foot really.
Also, I look at L feet as a small 2" x 2" flashing. Relative to the
hole size this is often a reasonable amount of sealing surface. Compare
this to your average 4" plumbing penetration vs the size of the
flashing. Look at how bulk head fittings on water tanks work. They're
under several feet of water, and depend on a rubber gasket, not a flashing.
I also consider what's under the roof too. A leak on an open carport is
not as much liability as a leak over the vintage Steinway grand piano.
Finally, if the roof is already having problems, (I love when they say:
"it only leaks when it rains"......) you need to look at re roofing,
and have the roofer seal around your mounts.
R.Ray Walters
CTO, Solarray, Inc
Nabcep Certified PV Installer,
Licensed Master Electrician
Solar Design Engineer
303 505-8760
On 4/11/2014 1:52 PM, Will White wrote:
I've had a similar experience as August.
We're using Ecofasten Green Flashing plus all holes get a dab of
Geocel Proflex. We've also never had a problem with a properly
flashed penetration.
Thanks,
Will
*From:*[email protected]
[mailto:[email protected]] *On Behalf Of
*August Goers
*Sent:* Friday, April 11, 2014 3:44 PM
*To:* RE-wrenches
*Subject:* Re: [RE-wrenches] Flashing vs Sealant... again (is sealant
code defensible?)
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:*[email protected]
<mailto:[email protected]>
[mailto:[email protected]
<mailto:[email protected]>] *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
[email protected] <mailto:[email protected]>
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