Hoping some experts can chime in with their opinions here. I am looking to have a solar pergola built and the size will be 20’ 8” x 17’ 5”. It will fit roughly 15 panels on it. At 50lbs a panel, that will put the weight on it at 750lbs. Just for the panels. Looking to use either 6” or 8” cedar or redwood wood posts. Can anyone recommend which would be best and how many posts I need to get this to pass Fort Worth city review? Would appreciate any and all help here! Thanks.
Solar Pergola Project - what size posts and how many?
- Thread starter capvent
- Start date
I can't chime in on the structural aspect, but I can say I like the idea of a pergola. Particularly if the panels are bifacial. I just finished installing six large bifacials as a roof system on a little pole barn. The diminished blue light coming through actually looks almost decorative. If finishing underneath could look less "industrial", it would be rather pleasant. Stylish, even.
what panels did you guys use? Any help on brand and model so I can review would be appreciated - thanks.
Mine are 400 w Trina biface. They actually look nice from underneath when the sun is on them.
Thanks - got any pics you can share? Thanks.
dougbert
Solar Wizard
GXMnow
Solar Wizard
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My pergola (mentioned above) might not meet code in some areas.
I have a total of 10 Hyundai 400 watt bifacial panels on it. That is about 500 pounds with the rails. I have it all on just 4 posts that are pressure treated 4x4's. The posts are 10 feet apart by 8 feet apart. Each post can support up to about 600 pounds of vertical load, so that is not the problem. But that is a rating for a deck which is fairly low to the ground. With my pergola being 8 feet up on one end and over 11 feet on the other end, it is handling side load from wind that I was concerned about. The current structure meets code here as a "sun shade", but the added weight of the solar panels probably takes it out of compliance. I could shake it around a little before the panels went up, but with the added weight, the natural frequency is much lower and it certainly looks like it moves more with the slower movement. In the worst winds we have had, it has barely moved though. Even with gusts hitting 90 MPH.
Here, we also have earthquakes from time to time. I have the corners well braced, but it will still sway a little. But if I give it a good shove, it can move a bit more than I was expecting, so I am thinking of adding an "X" brace on each end and maybe laminating an extra 2x4 onto the side of each post to add a little rigidity. That would make each one a 4x6. We had a 4.0 quake a while back, and that will certainly rock it quite a bit. Would hate to have a post crack and have it fall against the back of my house.
I have a total of 10 Hyundai 400 watt bifacial panels on it. That is about 500 pounds with the rails. I have it all on just 4 posts that are pressure treated 4x4's. The posts are 10 feet apart by 8 feet apart. Each post can support up to about 600 pounds of vertical load, so that is not the problem. But that is a rating for a deck which is fairly low to the ground. With my pergola being 8 feet up on one end and over 11 feet on the other end, it is handling side load from wind that I was concerned about. The current structure meets code here as a "sun shade", but the added weight of the solar panels probably takes it out of compliance. I could shake it around a little before the panels went up, but with the added weight, the natural frequency is much lower and it certainly looks like it moves more with the slower movement. In the worst winds we have had, it has barely moved though. Even with gusts hitting 90 MPH.
Here, we also have earthquakes from time to time. I have the corners well braced, but it will still sway a little. But if I give it a good shove, it can move a bit more than I was expecting, so I am thinking of adding an "X" brace on each end and maybe laminating an extra 2x4 onto the side of each post to add a little rigidity. That would make each one a 4x6. We had a 4.0 quake a while back, and that will certainly rock it quite a bit. Would hate to have a post crack and have it fall against the back of my house.
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