Porch pagoda build

Finally making some progress on my porch roof. This is going to be 24 panels, and will be a 2 part.

Materials is 2" square tube with 1/4" sidewall. I just got the base structure up, no bracing or webbing yet. It was the hard part, the rest is easy.

Got the legs stabalized with some wood posts. Then lifted the top piece in place, marked it, took it all down, cut it, put it back up, welded it for the 2 sides. Then when everything was sitting, I put the 24' long cross members up and welded them. This is the part I needed help with, I had a second guy lifting, as it was a bit dangerous to do myself.

Next step is the webbing that will brace the legs and support the long spans. It's a lot of pieces and a lot of cuts. I didn't buy enough, I only got 40'.

When I say webbing, this is what I'm referring to. Each piece will transfer the down force on the top to the leg to prevent sagging.

Can I mount the panels to steel angle iron? Or do I really need aluminum angle?

I'm making my own mounts that will run up and down, with the panels mounted sideways. The gap is 7 foot between the center and outer ones, with a 3' overhang, so the panels will "balance".

In the image below, the black lines are the steel cross you see in the above image. The orange lines are what I'm going to mount on those to attach the panels to, which don't exist yet. And the purple is the panels.



And here are some solar panels.

And a daylight photo of the structure so far.

What are the "panel supports"?

I would be concerned with those panels that are fully cantilevered from the "Big heavy steel" members with high bending stress in the "Panel supports" where circled.

sunshine_eggo said:

View attachment 231466

What are the "panel supports"?

I would be concerned with those panels that are fully cantilevered from the "Big heavy steel" members with high bending stress in the "Panel supports" where circled.

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I was going to do 2” angle aluminum but I am thinking I can do steel. I’m welding ears on the steel tube. Going up so I can bolt the angle aluminum to it.

I was also going to do ears on the bottom and a support brace going out to the end of the panel support to provide additional strength.

Angle has a torsional response to bending that compromises stiffness and stability. You can compensate by opposing the angle facings for each panel rail, i.e., they face each other or away from each other. Alternatively, C channel would be preferred and have notably higher strength and stiffness if you can make it work.

sunshine_eggo said:

Angle has a torsional response to bending that compromises stiffness and stability. You can compensate by opposing the angle facings for each panel rail, i.e., they face each other or away from each other. Alternatively, C channel would be preferred and have notably higher strength and stiffness if you can make it work.

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Since I'm ordering such a small amount, i'm at the mercy of what my distributor has on hand, no special orders. But I get commerial/bulk pricing, so that's pretty sweet. There's no aluminum C channel, but I can get the aluminum lengths in 20' lengths of angle and flat stock.

fatjay said:

Since I'm ordering such a small amount, i'm at the mercy of what my distributor has on hand, no special orders. But I get commerial/bulk pricing, so that's pretty sweet. There's no aluminum C channel, but I can get the aluminum lengths in 20' lengths of angle and flat stock.

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I meant to indicate prior that I would prefer steel as well as it's 3x stiffer and typically notably stronger unless you're buying premium structural aluminum like 7075.



If you have to use angle, on each run of panel supports, I'd orient them either as per red or black. They will want to twist in opposite directions and counter each other.

sunshine_eggo said:

I meant to indicate prior that I would prefer steel as well as it's 3x stiffer and typically notably stronger unless you're buying premium structural aluminum like 7075.

View attachment 231553

If you have to use angle, on each run of panel supports, I'd orient them either as per red or black. They will want to twist in opposite directions and counter each other.

Click to expand...

I’d like steel but I am concerned about galvinasation and the thin aluminum frame rotting away over the course of 20 years.

fatjay said:

Can I mount the panels to steel angle iron? Or do I really need aluminum angle?

Click to expand...

Our first lot of panels are directly on painted steel box section, no signs of corrosion after 5 years in a damp tropical climate.

Later sets are on aluminium extrusions now prices have become rather more competitive.




Panels are fixed using plates and long screws into the rails.
The plates are actually furniture joining plates with a hole drilled in the centre, primed and painted.