Roof install -- Why mount on rails? Why not mount on lumber?

[thomBangor]

On my roof install I am planning to use unistrut/easystrut/superstrut to attach my solar panels. I was looking at the mount-bolt hole pattern in the panel spec and it occurred to me that it would be very very easy to attach pressure-treated 2x4 to my roof, and then screw thru the mount-bolt hole patterns into the 2x4.

Any thoughts on metal vs wood?

I've ready some loosely-related stuff about not using wood for fire reasons... any merit to that?

Or perhaps metal rails are desirable so that the individual panels become one collective ground?

Thanks

 

[BackyardBandit]

Short answer: your roof will leak. Maybe not immediately but eventually. There are other reasons not to do this as well.

Long answer: rail systems have flashed feet installed to mount the rails to. There are new "flashless" rail mounting products available to accomplish the same end while maintaining the integrity of your roof, but properly flashed feet have been around a long time and are proven.

 

[ThaiTaffy]

On my roof install I am planning to use unistrut/easystrut/superstrut to attach my solar panels. I was looking at the mount-bolt hole pattern in the panel spec and it occurred to me that it would be very very easy to attach pressure-treated 2x4 to my roof, and then screw thru the mount-bolt hole patterns into the 2x4.

Any thoughts on metal vs wood?

I've ready some loosely-related stuff about not using wood for fire reasons... any merit to that?

Or perhaps metal rails are desirable so that the individual panels become one collective ground?

Thanks

Ask @timselectric I think he mounted his work of art to treated timber.

 

[mciholas]

How do you plan to ground your panels?

The typical solar panel racking system carries grounding to the panels.

For roof installs to meet code, they usually need to be grounded properly, and to have proper structural certifications.

Ground mounts are far less encumbered.

Mike C.

 

[dopeassjackson]

S5 brackets are what you should be useing.

PT can corrode any metal that it touches that's not hot dipped galvanized..even your roof. Dont do this for many reasons.

 

[timselectric]

Absolutely do not put PTL in direct contact with solar panel frames.
You have to put a barrier between them.