[RE-wrenches] Roof flashings on L-feet in high snow load conditions

William Miller william at millersolar.com
Tue Nov 13 16:51:16 PST 2012


Troy:

I do not know what a gravity flashing is.  Can you elucidate?

If you have adequate upload mounting strength and need more download 
support, you can consider using additional L-fee that simply rest on the 
shingles without penetrating the roof.  We do that sometimes to take the 
sag out of some DPW racking products if the span is long.  This should be 
an easy way to provide more snow load support.  The caveat is that, on 
pitched roofs, the resting feet do not provide any support down pitch.

William Miller

At 08:04 AM 11/13/2012, you wrote:
>Hi all,
>
>We have been doing PV installs for years with L-feet and silicone without 
>problems ever. Even still, gravity flashings seem attractive in shingle 
>roofs, to provide a second level of security, and a more professional 
>install (at least in perception). But the cost of these systems in 
>significant in high snow load areas where we often have L-feet every 2 
>feet on center, to evenly load the structure below. In todays costs, the 
>feet could cost as much as 33% of the panel value.
>
>I'm wondering what other people are doing in high snow load areas?
>
>Also. I have noticed that there is a flip side to the risks. We have found 
>that unless you have good quality shingles, on a preexisting roof, that 
>sometimes the adhesive sticking the shingles together is stronger than the 
>low quality shingles themselves - adding risk of trying to shoe horn 
>flashing in after the fact. Your experience?
>
>thanks,
>
>Troy Harvey




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