Solar Power: Day 9

As mentioned in my previous post the finish line for Phase 1 was right around the corner so the pergola crew only spent a few hours finishing up and then packed everything away and took their covered trailer that had resided in our driveway for the last week and a half.

The last of the corner braces was cut flush with the beams and the few problematic 2x6’s were given some final TLC. Finally the double stacked 2x12’s were notched at the ends and lifted into place. The reason for the notching was so we could use beam hangers (also from OZCO like the post plates) and forego having to notch the 2x12’s on top to fit into the 2x6’s.

The framework is complete!

And just like that the pergola is ready for a roof.

For the solar side of things the surveyors completed their work at sometime early in the morning because I had no idea they were even here until I saw the flag. Yep, just one flag. The only utilities (other than power) that come close to my power meter are phone and cable internet, and based on the orange markings I’m guessing they either share a conduit underground (we have underground utilities on my street) or were otherwise run together. But with the survey complete the trenching can now begin, which I hope happens tomorrow.

The trench will run from the Enphase interconnect box to the northwest corner of the pergola where a conduit will go straight to the roof and connect all of the panels that are to be mounted. I did ask a few months ago during the planning phase of this massive project if it were possible to tap into the line from the panels to the interconnect to provide power to the pergola and outdoor kitchen, but was firmly told no which I fully expected. The panels don’t have a disconnect switch at the pergola since there is one right next to the interconnect box, so even with circuit breakers in a sub-panel I would still need a disconnect switch at the pergola to shut the power down if I ever needed to work on something. That and it would be a code violation.

But speaking of the solar panels, there is an update on that. My solar engineer went over the structural numbers again for the pergola roof and he determined that ultimately putting twenty eight panels on top was going to be too much. The deciding factor was how far the roof would overhang the 4x12 beams and even with how well built everything is there wouldn’t be enough support for the very edges. Aesthetically this would lead to a droop over time. Structurally speaking it would be extra leverage in favor of high winds during a wind storm.

Not even 1” thick plywood would stop this roof from sagging, and it would cost a fortune anyway

In light of this the panel count is being dropped to twenty four, which is what I had originally planned for on my own. With nineteen panels already mounted on the house, this leaves the remaining five panels being mounted on the south roof. This I am perfectly fine with because at present only half of my house roof is covered, and these would, to channel Jeff Bridges, really tie the roof together.

Now the overhang will never sag

The order now calls for 1x12 boards that will essentially be assembled like a deck with staggered seams. They’ll be rabbeted to create a shiplap pattern, which should look very nice from down below. On top of the boards will go a layer of either 3/8” or 1/2” pressure treated plywood (the thickness is down to availability). The final layer consists of roofing felt (or something similar) and a layer of flat shingling. We originally looked into getting Thermoplastic Polyolefin (TPO) since it’s white and would potentially create a little more power generation since my solar panels are bi-facial, however only two suppliers within 100 miles had this material and it cost a fortune. Oh well. Add facia boards and drip edge around the perimeter and the roof is completed. If any of this is confusing I’ll go into more detail about this when roof construction actually starts since I was only told these details over the phone and I don’t have a completely visualized concept of this yet.

With that I’m relieved and pleased to say that Phase 1 is complete. Phase 2 will be the roof construction and solar panel mounting, along with the conduit trenching and (hopefully) final electrical connections for the panels and my interconnect. Phase 3 will be the expansion of the concrete pad around my pool to include the pergola footprint as well as the adjacent area next to the house where my outdoor kitchen will go. Phase 4 will be the construction of the wooden privacy fence along two walls of the pergola. And finally Phase 5 will be the construction of the outdoor kitchen.

Onwards and upwards? Shouldn’t that be reversed since the roof is going up and THEN onto the supporting structure? Weird saying.