[RE-wrenches] Metal roof support flashing

[Laura Uhler]

Hi,

I agree that sealant should be placed in the pre-drilled holes.  In my 
notes, I wrote to use a butyl sealant as it does not degrade.  However, 
I'm not a chemical engineer or roofer, and definitely I don't claim to 
understand why.  In talking with the roofer, I asked how I could achieve 
a 40+ year solution, and that was the advise I was given.  I also agree 
that penetrating any roof is a huge potential liability and should not 
be done lightly.

Almost all of the double layer of EternaBond stays under the L-foot - 
only about a 1/4 inch bulges out the sides and into the center hole. 

Hope that helps,

Laura

-- 
Laura Uhler
Electrical Engineer
NABCEP Certified PV Installer
Solar Ki, LLC
Corvallis, Oregon
(541) 602-6909
laura.uhler at solarki.com
www.solarki.com



Kelly Keilwitz, Whidbey Sun & Wind wrote:
> Laura,
> I attended that seminar, too....the statistics on the overwhelming 
> high percentage of liability cases being due to water incursion into 
> the building made me sit up and pay attention.
>
> Do you know if the "EternaBond" sealant is compatible with 
> polyurethane sealant? I would prefer to fill our pre-drilled holes 
> with sealant before applying the lag bolt. Does enough of the 
> tape/sealant remain under the stanchion base to maintain separation 
> between the metals?
>
> Thanks,
> -Kelly
>
> Kelly Keilwitz, P.E.
> Whidbey Sun & Wind, LLC
> Renewable Energy Systems
> NABCEP Certified PV Installer
> 987 Wanamaker Rd,
> Coupeville, WA 98239
> PH & FAX 360-678-7131
> sunwind at whidbeysunwind.com
>
>
> On 6/18/09 5:36 PM, "Laura Uhler" <laura.uhler at solarki.com> wrote:
>
>     Hi,
>
>     I talked with the roofer who gave the "Best Roofing Practices for
>     PV" course at the NW Solar Expo, and at the Oregon Dept of Energy.
>      I then took his recommendation and ran it by two local roofing
>     professionals, who similarly approved.  They recommended using the
>     EternaBond "Tape" product.  It looks like a 1/4" thick pre-rolled
>     roof caulking.  I get it in 2" wide rolls, or, you may be able to
>     purchase it pre-cut.  (It's not cheap.)  You peel off the plastic
>     outer layer and put it on the back of the L-feet.  I put on a
>     double layer.  It becomes activated by pressure, so, when you
>     screw your stainless steel lag bolts (with washers) into the
>     underlaying rafters, the EternaBond will ooze up in to fill the
>     cavity between the washer and oval L-foot hole.
>
>     I'd recommend that you allow yourself several hours to cut the
>     EternaBond and pre-apply it to the L-feet before bringing the
>     hardware on the roof.  That way, only the final layer of plastic
>     needs be removed before screwing the L-foot onto the roof.  But,
>     be warned, even with a top plastic layer on the "tape", the
>     EternaBond will stick to everything!   There is no doubt that this
>     is a much more solid, waterproof connection than the dollops on
>     caulking around the six screws that must hold down every boot.
>
>     Good Luck!
>
>     Laura
>
>
>
>
>
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-- 
Laura Uhler, Owner
Solar Ki, LLC
(541) 602-6909
laura.uhler at solarki.com
www.solarki.com


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