Solar Heating on Roof

Any facts about needing an engineers report for the added weight of a Solar Water Heating System on the roof?

Does this help?

Yes, thanks…was looking for something that suggested making sure the truss system was adequate and even though you are in FL, it should be sufficient. Thanks again.

Not you but the article…Sorry

With the additional use and types of solar heating we’ll be seeing… this and the installation on concrete tile roofs should be interesting.

I drove by the other day and could see them “chipping” some holes in the tiles to install the mounts for the solar collectors… ooops.

Good topic Paul. Thanks


I wish whoever installed my neighbors panels had done that. During Wilma, his solar panels and the tiles they were mounted to, ended up tearing off one of the side awnings to my house and then, the tiles crashed through my hurricane rated door window, which landed in the living room!:shock::shock:

The added weight of the panels and water wasn’t that much, but they do need to be secured to the roof framing, so they don’t end up down the street…

Secured yes… an un-sealed/flashed hole through the tiles for the mounts?.. the installer can do better.

Does anyone know what kind of weight these panels typically are?

Guess that does add a bunch of weight if you have quite a few of them. Thanks Jeff

Notice it listed “dry” weight, but not “wet” weight. My guess would be closer to 100 lbs (panel alone) when filled. Depending on the system I would assume 4 panels minimum.

Adds up quick.

Went to a course on this issue. Was taught by a structural engineer. Going Green. Course was at WE Energy our local power company.

There are calculations the structural engineers use. The fasteners and locations are critical. The weight and location of the panels are critical. In this part of country snow load has too be calculated. The proper amount of trusses and support needs to be adequate for all this weight. There was discussion as far as new construction where most new trusses are 24" on center, versus old home construction that are 16" on center. 2 x 4 versus 2 x8, or 2 x 10.

Flashing and proper installation critical. Generally installations are 3 trade project. Example, carpenter, glazier, HVAC trades.

As Home Inspector’s something to learn about for inspection purposes.

It’s a science in itself. Permit required in our area. Prints need to be by architect, PE, or licensed design professional.

In Boulder County, a P.E. must sign/stamp off on solar panel supports, even if they are not on the roof (ground mounted), because of the danger of them blowing away.

I agree, the danger is uplift and positive wind load more than additional weight. The weight is spread over the roof, so the point loads are not great, but if the home is located in a high wind area, these things can take off.
Newer systems are evacuated tube (first photo) instead of flat plate collector, making them lighter and more wind resistant.

collector 2.jpg

Collector 1.jpg