ᐅ Solar panels on the garage roof

Good morning everyone,

The year before last, I built a wooden garage.
I designed everything myself, and a structural engineer calculated all the details. The base dimensions are 9 m (30 ft) wide by 7 m (23 ft) long, with a central support post located at 6 m / 3 m along the length.
There are three purlins, each measuring 12 cm by 24 cm (5 inches by 9.5 inches), and rafters of 8 cm by 12 cm (3 inches by 5 inches) spaced 0.75 m (30 inches) apart, with a roof pitch of 7°.

Now I am wondering if this structure can support a photovoltaic solar system and possibly a solar thermal system.

Can anyone tell me where in the structural calculations I can check or how to calculate this?
Should I simply calculate with an increased snow load?

Thanks and best regards

The garage already has a roof.
The snow load does not change.
Photovoltaic panels weigh hardly anything.
Solar thermal system: about 45 kg (including approximately 2 liters) on about 2.3 m² (25 square feet)
A roofer on the roof has more mass per area.

OK, sometimes things are taken very precisely, especially when it comes to structural engineering. By higher snow load, I meant accounting for an increased snow load instead of just the weight of the solar system.

Let's take it slow. Even though a photovoltaic system itself doesn’t weigh much, here we are dealing with a mounting structure. That brings up the issue of wind load, which can be addressed, for example, by adding extra ballast.

Aside from that, I can’t help but say that mounted photovoltaic or solar thermal systems on garages are an aesthetic eyesore. Think about that carefully.