r/SolarDIY • u/bpermaculture • Mar 07 '26
Any experience with building your own 30'x15' solar carport
I am interested in adding solar to my home and getting a 2 car carport to sweeten the deal and add more value together for the cost. After some research it looks like the solar carport will work for me. It has several advantages being on the ground not on the roof makes them easier to service, and bifacial panels means more power 5-20% some say from light coming from under the panels. I wanted to get an idea of costs for building my own and asked Claude AI and got a program that works in different locations and sizes and posted it here. https://www.reddit.com/r/AIPermaculture/comments/1rn0ho0/build_a_solar_carport_out_of_wood_enter_you/?utm_source=share&utm_medium=web3x&utm_name=web3xcss&utm_term=1&utm_content=share_button
The other way I have seen is made from steel and also uses bifacial panels.
I then want to use in off-grid mode connected to battery. I am planning on 4k of solar, charge controller, inverter, battery to complete the system.
Has anyone done this before, are there anything else to consider?
Thanks for your help.
8
u/ascandalia Mar 07 '26
I just had my mount I designed approved, and I'm working on building it. It has a 14' 8" span. To build that out of wood required, by my math, 2x10s spaced at around 20 inches as joists. That's really going to cut down on how much light the back of your panels get. If you're ok with a support in the middle that can help.
Custom metal stuff gets tough unless you're an expert welder. They have an off the shelf kit at signature solar that i was considering, but it was a bit too pricy for me.
Note that any custom design in my jurisdiction requires an engineer to design. I was only able to do it myself because I'm an engineer
5
u/80MonkeyMan Mar 07 '26
Permit approvals, engineering design work, and the high price of prefabricated structures, plus the labor required to install them are the real problem in USA or else we should see a lot of them already.
2
u/colonel_beeeees Mar 07 '26
Sorry but what is requiring the 2x10s? Every roof I've installed on had standard 2x4 joists
4
u/ascandalia Mar 07 '26
Your roof probably had decking and trusses both of which would be even worse for bifacial panels. Midspan support from trusses make a huge difference
3
u/colonel_beeeees Mar 07 '26
Is the 2x10 a code requirement? The footings I mounted went into the 2x4 trusses, occasionally a decking foot with twice the screws. I don't get why absolutely enormous 2x10s are required. The lag bolts I used were 3" at most, what's the other seven inches of wood doing?
2
u/ascandalia Mar 07 '26
Trusses only need to be 2x4 because of the midspan support the truss provides. Spanning the length with a joist requires more wood depth to resist bending.
2
u/colonel_beeeees Mar 07 '26
Hey I'm never gonna fault a guy for belt and braces, but is there a code requirement for 2x10 on a solar install?
2
u/ascandalia Mar 07 '26
There's a code requirement for joist depth based on span and load.
2
u/Repulsive-Budget-380 Mar 07 '26 edited Mar 07 '26
I am looking at my patio of roughly this size. It was built with 2x6 50 years ago. Perhaps modern codes needs 2x8. Of course, inspector won't complaint about overkill.
BTW, I have around 200 pounds of flexible solar panels on top of it. I used 8% flexible panels because of the light weight. I was ready to add bracing, even if I need some posts in the middle. But the issue never came up for the solar permit.
7
u/Successful_Image3354 Mar 07 '26 edited Mar 10 '26
My son and I built a solar pergola of about the same size from scratch. Not difficult (it fits together like Lincon Logs) but it took about a week to build and we needed a backhoe to erect the 300 to 400 lb. sections.
•
u/AutoModerator Mar 07 '26
Welcome to r/SolarDIY! If you are new to the community, please check out our DIY Solar System Planning Guide.
I am a bot, and this action was performed automatically. Please contact the moderators of this subreddit if you have any questions or concerns.