[RE-wrenches] to flash or not to flash

Jason Szumlanski jason at floridasolardesigngroup.com
Fri Aug 7 14:50:13 PDT 2015


http://www.oatey.com/brands/oatey/regions/canada/products/flashings/roof-flashings/retro-master-flash-roof-flashings

Well, the manufacturer calls it a flashing, but I agree that were talking
semantics here. Flashing, in the code sense, is applied liberally in
practice. The washers on the thousands of screws on a 5V metal roof must be
flashings, otherwise these roofs do not meet IBC, right? Same goes for
vents with boots... Unless you don't call fasteners penetrations, in which
case you can't hold solar attachment fasteners to a different standard. I
realize that logic escapes code writers and interpreters sometimes, but I
think rational people can see it both ways. There are plenty of metal roof
products that are sealed (flashed?) with EPDM gaskets or butyl tape
(Sunmodo, Eco-Fasten, S-5, etc.), that are successfully implemented in real
world scenarios.

There are really two issues here: clarifying what is acceptable from a code
perspective, and industry best practices. Both issues have interpretations
and preferences, most with merit and based on lots of experience.

Martini shaken or stirred? We're probably not going to agree on a single
solution as an industry.

I have metal flashings on my shingle roof at home - it's my preference, but
I don't think it is a requirement, nor do I think "unflashed" fasteners are
unacceptable.


Jason


On Fri, Aug 7, 2015 at 5:11 PM, Kurt Johnsen <kjenergysystems at gmail.com>
wrote:

> Not that the names of things matter that much but imho "flashing" does
> require an overlapping of some kind. An Oatey boot for a metal roof is more
> of a bedded fitting than a flashing. It relies entirely on fasteners and a
> sealing membrane whereas flashings rely mostly on natural forces like
> gravity. Perhaps an experienced roofer weigh in on this.
>
> Kurt Johnsen
>
> On Fri, Aug 7, 2015 at 3:21 PM, Jason Szumlanski <
> jason at floridasolardesigngroup.com> wrote:
>
>> "If you place a flat object on top of roofing without an uphill material
>> lapping over the downhill object, you are not flashing. "
>>
>> By that logic, an Oatey boot is not a flashing for a plumbing vent on a
>> metal roof.
>>
>> Just sayin'...
>>
>>
>> Jason Szumlanski
>>
>>
>> On Fri, Aug 7, 2015 at 2:19 PM, William Miller <
>> william.miller at millersolar.com> wrote:
>>
>>> Ray:
>>>
>>>
>>>
>>> I have to respectfully disagree with your semantics.  A flashing is an
>>> overlapping of roofing materials such that gravity will direct rain and
>>> melt water off of the roof.  This is a universally accepted waterproofing
>>> method that does not depend on any sealant material.  The concept is as
>>> ancient as the first, crude, thatched roof.
>>>
>>>
>>>
>>> If you place a flat object on top of roofing without an uphill material
>>> lapping over the downhill object, you are not flashing.
>>>
>>>
>>>
>>> What you have described is sealant-dependent weatherproofing.
>>> Regardless of the quality of the sealant, or lack thereof, I don’t think
>>> you can call it a flashed attachment.
>>>
>>>
>>>
>>> (The overarching point is a flashed attachment does not depend on a
>>> sealant.  Any sealant has a finite lifespan.  Removing the sealant variable
>>> from the equation results in more lasting installation.)
>>>
>>> Sincerely,
>>>
>>>
>>>
>>> William Miller
>>>
>>>
>>>
>>>
>>>
>>> [image: Gradient Cap_mini]
>>> Lic 773985
>>> millersolar.com <http://www.millersolar.com/>
>>> 805-438-5600
>>>
>>>
>>>
>>> *From:* RE-wrenches [mailto:re-wrenches-bounces at lists.re-wrenches.org] *On
>>> Behalf Of *Ray Walters
>>> *Sent:* Friday, August 07, 2015 10:34 AM
>>> *To:* RE-wrenches
>>> *Subject:* Re: [RE-wrenches] to flash or not to flash
>>>
>>>
>>>
>>> My opinion is that if the L foot has enough surface area it constitutes
>>> a flashing, and that large flashings can actually cause more damage to the
>>> roof than they prevent.
>>> I also agree that an attachement doesn't constitute a penetration.  I
>>> just finished an install on a metal roof with hundreds of screw holes.  We
>>> added a few more screw holes, and ours have 20 times the sealant surface
>>> area.  We did run a 1" conduit through the roof, and since it was an actual
>>> penetration, we used a very expensive flexible boot flashing.
>>> Personally, I think we need about a 3"x3" or 4" x 4" L foot with a
>>> double stick butyl tape on the bottom, and all will be well.
>>> I realize that the OP was referring to asphalt, but I will flash other
>>> roof types that don't do well with L feet ( like shake).
>>>
>>>
>>>
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>>
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