[RE-wrenches] to flash or not to flash

Mon Aug 31 06:36:32 PDT 2015

We see a lot of similar issues with old systems “flashed” with sealant alone.  On the surface things look ok, but hardware is loose, rafters are rotted, and it’s not uncommon to find water stained rafters in the attic.  See photos attached of a recent inspection I did.  Connections were made using large 3”x3” U-brackets and lag bolts sealed to the roof with goop.  Many connections had developed leaks, rafters rotted, and one had cracked.  Customer had no idea that there was an issue.

I’ve read some persuasive arguments against flashings on this thread, but in the end my experience is that there are far fewer issues with a quality, manufactured flashing on a comp shingle roof as opposed to sealant alone.  

In my opinion installer error is not a good reason to stop using flashings.

Garrison

Garrison Riegel

PV Operations Manager |  <http://www.solarserviceinc.com/> Solar Service Inc

[p] 847-677-0950 |  <mailto:garrison at solarserviceinc.com> garrison at solarserviceinc.com

NABCEP Certified PV Installation Professional™

From: RE-wrenches [mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of Jerry Shafer
Sent: Saturday, August 29, 2015 5:13 PM
To: RE-wrenches <re-wrenches at lists.re-wrenches.org>
Subject: Re: [RE-wrenches] to flash or not to flash

I have been in attics and had to chase down water leaks, I have moved the hardware from older (15 + years) and there are a lot over leaks from the "before flashing days" and what I have seen is that once you remove the hardware, the bracket comes loose very easy as all or near all of the comp has cracked away from the surrounding material and there is a clear shot to the wood. Flashing is a must in my book
Jerry

On Aug 25, 2015 3:41 PM, "frenergy" <frenergy at psln.com <mailto:frenergy at psln.com> > wrote:

I've dancing around the perimeter of this discussion but now wish to make that one more not to flash.  There are many ways to do any job. I have been attaching things to roofs and cutting holes in roofs for a couple trades for 38 years and have yet to discover (or have a customer discover and contact me) any damage from water.  When attaching feet to a roof for a PV rail system,  I do not flash...I have but can't justify the time and cost for my perceived lack of benefit. When I cut a hole in a roof, I flash.

        I think its all about the correct caulking for the particular kind of roofing material (one type does not fit all), proper preparation of the attachment location, insuring there is plenty of wood for the fastener, laying a liberal bead and proper torque of the fastener.  $.02

Thanks,

Bill

Feather River Solar Electric
4291 Nelson St.
Taylorsville, CA  95983
530.284.7849 <tel:530.284.7849>  / 6544 fax

solar powered since 1982

From: Daniel Young <mailto:dyoung at dovetailsolar.com>  

To: 'RE-wrenches' <mailto:re-wrenches at lists.re-wrenches.org>  

Sent: Tuesday, August 25, 2015 2:19 PM

Subject: Re: [RE-wrenches] to flash or not to flash

Figured I would dig through the responses to this list topic since I posted it as a poll, of sorts.

My final count was: 10 votes to flash, 4 votes not to flash.

Those who read all the responses probably know there are a few on either side that would be OK with the other option.

I’m still on the flashing side of things, though I might consider letting the client have a choice. If I explain the differences, and show them the $ difference, they can help make the decision (read that as? “take some liability off of me :)”). We do that now with US vs non-us made solar modules. It’s not the same type of comparison here, but at least if the client really wants a lower cost, they know how they’re getting it, and future calls from the client should get tempered by the knowledge that they chose the attachment method.

Some really good points were raised on this topic, thanks to everyone who participated.

With Regards,

Daniel Young, 

NABCEP Certified PV Installation ProfessionalTM: Cert #031508-90

From: RE-wrenches [mailto:re-wrenches-bounces at lists.re-wrenches.org <mailto:re-wrenches-bounces at lists.re-wrenches.org> ] On Behalf Of Jason Szumlanski
Sent: Monday, August 10, 2015 5:42 AM
To: RE-wrenches
Subject: Re: [RE-wrenches] to flash or not to flash

Although my mind is kinda' made up, this thread has really got me thinking and researching. I scoured the NRCA manual, which does not really define "penetration," but it does say in the shingle manual:

"Penetration Flashings: There are many small penetrations that need to be flashed into asphalt shingle roof

systems, such as vent pipes, exhaust vents, exhaust fans, furnace or water heater flue pipes, electrical standpipes and others."

There is also a graphical figure showing these various penetrations. The one thing these all have in common is that there is a substantial air gap cut fully through the roof plane.

It occurred to me that ridge caps and vents on shingle roofs use exposed fasteners to nail or screw them to the decking. The NRCA manual says about this:

"Exposed fasteners should be sealed with elastomeric sealant or asphalt roof cement on the last ridge piece of a run, at the intersection of hips to a ridge and at the intersection of a ridge to another plane."

Also read the Snow Guard section for metal roofs, which allows attachments sealed to the flat part of the roof pan with sealants.

Until the manual specifically addressed the solar "attachments" and "fasteners" we are debating about, it's open to interpretation.

On Fri, Aug 7, 2015 at 5:50 PM, Jason Szumlanski <jason at floridasolardesigngroup.com <mailto:jason at floridasolardesigngroup.com> > wrote:

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, and would be prohibited, right? Same goes for vents with screwed and sealed boots... Unless you don't call fasteners penetrations, in which case you can't hold solar attachment fasteners to a different standard. 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. 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 completely unacceptable.

Jason

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

Lic 773985
millersolar.com <http://www.millersolar.com/> 
805-438-5600 <tel:805-438-5600> 

From: RE-wrenches [mailto:re-wrenches-bounces at lists.re-wrenches.org <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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