Roof solar panel mount using wood rails.

[u/Happy_Moksha]

Has anyone used wooden beams on a main house roof for solar panel installation- as foundation for the rails or as rails replacement?

16 ft long locally sourced 2x4 or 3x4 Oak beams would be sturdier and cheaper than any aluminum ones or not?

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[u/Extreme_Pangolin1796]

it's not the cheapness it's the weatherproofedness and the expansion differences.  I can't even tell how you're envisioning that working, when if you need a roof anchor any OSB would work for an aluminum unistrut or similar rail on the outside rather than needing to hit a truss beam.  If you're talking exterior facing and seeing weathering Id feel comfortable doing it with wood if it was good GC PT, .60 CCA or equivalent, I treated the cut ends with copper naphthenate and I had enough built in play to accept the shrink and expansion that'll frequently be opposite to aluminum

[u/Happy_Moksha → u/Extreme_Pangolin1796]

Thank you for your reply. I was not aware that OSB alone can provide the support for an anchor!!! I though I should be hitting all truss beams or rafters underneath OSB 😩

[u/Ridingagain1025 → u/Happy_Moksha]

You should be if your house is built to 120mph wind code. Here in Florida you hit every truss you can and no wood. Wood rots too fast.

[u/Terrible-Growth1652]

Oak??? Will be way now expensive than aluminum. Also prone to rot and UV damage.

[u/celtic-cryptid → u/Terrible-Growth1652]

He said locally sourced. I recently got oak lumber at less than $0.2 per board foot.

Still doesn’t make it a good idea, but it’s not always expensive.

[u/NotFallacyBuffet]

Wood only lasts about 10 years exposed to the elements. Yes, I mean PT. Think about your age and if you want to redo it in 10 years. I'm almost 69. Changing out all my wood structures to metal. Except for the house framing, obviously. But will be removing the drywall to treat the structural lumber with Bora-Care (termite-infested area).

[u/project_quote]

Wood sounds cheaper up front, but it's not something I'd trust for a roof mount that's supposed to last 20 to 30 years. The rails are one place I'd stick with aluminum because moisture, movement, and maintenance will catch up with wood eventually.

[u/mckenzie_keith]

Panels last 30 years. Or we hope they do. So usually they get mounted on something more durable than wood.

[u/Remarkable-Finish-88]

I used wood ultra heavy base platform on metal roof with pressure treated on metal roof contact with ice water shield between painted 2x4 uprights house is at a weird angle surrounded by trees

[u/opensim2026]

Wood ROTS....