Need a book? Engineering books recommendations...

Return to index: [Subject] [Thread] [Date] [Author]

Re: Photovoltaic panel weights

[Subject Prev][Subject Next][Thread Prev][Thread Next]

     Solar panels tend to shed snow (slippery surface). Depending on your 
roof material and slope (e.g. asphalt shingles), you might realize a snow 
load reduction in the area of the panels compared to the bare roof if the 
snow is free to slide off and go elsewhere (panels close to eaves perhaps) 
any snow shed from the panels has to go somewhere however, so you could have 
 a drift wherever any such snow might end up (lower roof, break in slope 
etc). Then again snow downslope on a non-slippery roof might hold it all on 
the panels if the snow is deep enough and panels close enough to the roof. 
Conversely you could have your panels effectively acting as snow bars and 
holding snow upslope on an otherwise slippery roof (eg standing seam). These 
 types of things come up from time to time on existing roofs that were not 
designed for solar panels. Panel installation has the potential to effect 
the snow loads and their distribution to the underlying roof structure.

- Mike

Drew Morris <dmorris(--nospam--at)> wrote:

> The panels are supposed to be flush to the roof so won't add snow drifting. 
> On 3/17/2014 1:41 PM, Paul Blomberg wrote:
>> We just went through this and I just received actual loads in a
>> submittal. We average out at 3.5 psf for the PV's, frames, roof mounts
>> and misc.
>> conduits.
>> I used to have 12 psf for the photovoltaics but that is very
>> conservative.
>> If you are in snow country, have fun calculating the roof snow
>> contribution.
>> Paul.
>> Phoenix, AZ
>> On Mon, Mar 17, 2014 at 12:34 PM, Drew Morris <dmorris(--nospam--at)> wrote:
>>> I have a project were the client is interested in putting on a roof
>>> mounted flush photovoltaic array on a new building.  The client is
>>> researching through the vendors but i need to get an approximate dead

Truncated 307 characters in the previous message to save energy.

Post your message to the list by sending it to: 

The email messages sent to the list will be saved in an archive on the World Wide Web.
These archives are located at:

To contact the list owner, send your message to:

Sponsored By: Pacific Structural & Forensic Engineers Group, Inc. (PSFEG)

To unsubscribe, switch to/from digest, get on/off vacation, or change your email address, click here.