Hello,
I am considering installing a photovoltaic system on the roof. Is the roof load capacity generally sufficient nowadays? Specifically, can the existing roof load support a photovoltaic system on one side of the roof, or is it necessary to have the roof load capacity increased? Where exactly can I find information in the structural engineering documents about the current roof load? The roof is a pitched roof with a 45-degree angle.
A solar installer I contacted said there is no problem, and that he has never encountered issues with the systems he has installed so far. Another aspect is that when someone installs a photovoltaic system after several years, it is usually done "simply" or straightforwardly.
Does anyone have any thoughts or even personal experience on this?
Thank you!
I am considering installing a photovoltaic system on the roof. Is the roof load capacity generally sufficient nowadays? Specifically, can the existing roof load support a photovoltaic system on one side of the roof, or is it necessary to have the roof load capacity increased? Where exactly can I find information in the structural engineering documents about the current roof load? The roof is a pitched roof with a 45-degree angle.
A solar installer I contacted said there is no problem, and that he has never encountered issues with the systems he has installed so far. Another aspect is that when someone installs a photovoltaic system after several years, it is usually done "simply" or straightforwardly.
Does anyone have any thoughts or even personal experience on this?
Thank you!
H
hampshire22 Jun 2019 07:54Don’t just consider the roof load but also the wind load.
Additionally, check the fire protection requirements and the fire load registration.
“I’ve always done it like this” from the solar installer (rarely a roofing specialist, usually an electrician) would not be sufficient for me.
Additionally, check the fire protection requirements and the fire load registration.
“I’ve always done it like this” from the solar installer (rarely a roofing specialist, usually an electrician) would not be sufficient for me.
And also regarding the snow load
No, I don’t think there should be any problems. For example, our roof is not even allowed to have roof tiles, but photovoltaic panels are always allowed. The modules are so extremely light that they do not cause any issues. In our case, the structural engineering was definitely reviewed. That means I dug up the documents and copied them to the solar installer.
No, I don’t think there should be any problems. For example, our roof is not even allowed to have roof tiles, but photovoltaic panels are always allowed. The modules are so extremely light that they do not cause any issues. In our case, the structural engineering was definitely reviewed. That means I dug up the documents and copied them to the solar installer.
H
hampshire22 Jun 2019 11:03Pressure and suction are two different directions of force impact. Depending on how the house is positioned and how the system is installed, you effectively create a few square meters of "sail area" on it. Combined with unfavorable attachment points, a strong storm can damage houses built in Germany to the point of structural failure risk.
There are a number of standards and surprising gaps in their application. For example, it is sufficient if the solar installer provides a description of the substructure. This is inexpensive and considered compliant. Therefore, solar installers usually keep it simple—they are electricians, not structural engineers, and everything that complicates the sale is left out as much as possible. In the event of damage, however, the insurer will want to see an expert report that verifies wind and snow loads.
Of course, it is up to the original poster how they approach this issue. In my opinion, ignoring wind load is somewhat comparable to driving a car without a seatbelt. Many do it and can report that nothing happened.
There are a number of standards and surprising gaps in their application. For example, it is sufficient if the solar installer provides a description of the substructure. This is inexpensive and considered compliant. Therefore, solar installers usually keep it simple—they are electricians, not structural engineers, and everything that complicates the sale is left out as much as possible. In the event of damage, however, the insurer will want to see an expert report that verifies wind and snow loads.
Of course, it is up to the original poster how they approach this issue. In my opinion, ignoring wind load is somewhat comparable to driving a car without a seatbelt. Many do it and can report that nothing happened.
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