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diy solar

Solar shed roof?

cdevidal

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Sep 12, 2021
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Anyone have plans for installing a shed but with panels for the roof? Saw this design on Watts247.com but the owner of the site didn't answer my question of the details about how he did it. Looks like it might be 6" pressure-treated posts, doubled-up 2x6 beams, 2x4 joists on joist hangers, then some 1x2 purlins. But I'm not sure my estimate is correct. If I tried to do that and it was wrong, having it collapse would be bad news.

My upcoming design is tentatively 2000W.

208WRoof.jpg
 
Anyone have plans for installing a shed but with panels for the roof? Saw this design on Watts247.com but the owner of the site didn't answer my question of the details about how he did it. Looks like it might be 6" pressure-treated posts, doubled-up 2x6 beams, 2x4 joists on joist hangers, then some 1x2 purlins. But I'm not sure my estimate is correct. If I tried to do that and it was wrong, having it collapse would be bad news.

My upcoming design is tentatively 2000W.

208WRoof.jpg
I have not done it but I see the pic differently. I see 4" round Steel post, Doubled 2x6 Beams (Except at posts), 2x6 joists and 2x4 Purlins....
 
I just made something practically the same.

Here is my "sort of build":

 
Anyone have plans for installing a shed but with panels for the roof? Saw this design on Watts247.com but the owner of the site didn't answer my question of the details about how he did it. Looks like it might be 6" pressure-treated posts, doubled-up 2x6 beams, 2x4 joists on joist hangers, then some 1x2 purlins. But I'm not sure my estimate is correct. If I tried to do that and it was wrong, having it collapse would be bad news.

My upcoming design is tentatively 2000W.

208WRoof.jpg

That appears to be traditional framed panels, butted together.
How would you make the roof water tight?

The wood should be strong enough, barring snow loads.
But I don't love using nails to support the weight. Or do those sheet metal joist hangers wrap over the top edge?

iu
vs.
iu
 
Definitely 2x8 or 10 and 2x4. Steel posts. When it comes to roofing I have always said “ sealant should not be the primary defense but secondary” I might store hay or something but not the rest of the solar build.
 
I have always said “ sealant should not be the primary defense but secondary”
How about a tarp between purlins and panels? I'm storing things that are outdoors-tolerant such as camping gear, sealed buckets, things like that. Stuff I don't want constant rain on but which can tolerate some dampness.
 
First, pressure treated (unless it’s cca) is not aluminum friendly at all. ACQ is corrosive.

Second, silicone is an acceptable filler in some applications but is definitely a poor idea for sealing a roof. Butyl rubber or polyurethane might do it- I’ve used polyurethane or its advanced cousin 5300 below the waterline for years.

Third, sealing under a roofing component is not preferable; top sealing with the advanced ‘tape’ used on aluminum utility trailers might do it.

Fourth: why would you EVER use silicone for anything?! It’s acidic at application, water creeps under leading to corrosion, it doesn’t even stick to itself and other stuff won’t stick to it making repairs iffy, it might ‘last’ fifty years but adhesion fails early, and it degrades in uv. It’s only advantages are that it’s inexpensive, readily available, and functions ok for glass, plastic, or metal components assembled against fiberglass.
 
Even if aluminum frames are sealed together with silicone or other material, joint between glass laminate and frames isn't necessarily waterproof. Aluminum frame is slipped over edge of glass and has silicone, but for some large panels with small frames, it will spring away if you lift by one edge.

The roof is almost flat, so water will pool and drip through if it can.

Ideally, the panels would be laid as tiles on top of each other so water spills. Frames 1" to 2" tall aren't ideal for that. A different design frame could overlap lower panels. For adjacent panels, something like a gutter between and underneath could carry the water down to spill on lower panels.

Or frameless glass laminates could be placed on a roof framing structure designed to match their dimensions, overlapping the one below and relying on caulk between adjacent ones.

I once saw pictures of such tiles GE made using the panels of AstropPower, which they acquired. Can't find pictures now.

 
That appears to be traditional framed panels, butted together.
How would you make the roof water tight?

The wood should be strong enough, barring snow loads.
But I don't love using nails to support the weight. Or do those sheet metal joist hangers wrap over the top edge?

iu
vs.
iu
joist hanger nails are appropriate for this load. Bending over the top is fine but overkill in most applications. (But I do it sometimes)
 
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First off I was a House Framer for 35 yrs --- I can never understand the logic of putting the beams on the side of the post --it's much better to have your beans sitting on top of a saddle welded to the post --then there's the Almighty joist hanger --- If you want real strength put your joist on top of your beams with a Band joist on the end --with joist hangers you're depending on the nails to hold your load
As far as the roof -- I would put a plywood roof with at least a type of roll roofing product under my panels --butting together without a flashing will leak like a sift -- JMTS
 
First off I was a House Framer for 35 yrs --- I can never understand the logic of putting the beams on the side of the post --it's much better to have your beans sitting on top of a saddle welded to the post --then there's the Almighty joist hanger --- If you want real strength put your joist on top of your beams with a Band joist on the end --with joist hangers you're depending on the nails to hold your load
As far as the roof -- I would put a plywood roof with at least a type of roll roofing product under my panels --butting together without a flashing will leak like a sift -- JMTS
How would you do the beams, two side-by-side like he did or a 4" wide or something else?
 
Bending over the top is fine but overkill in most applications. (But I do it sometimes)
…actually he was referring to top-mount joist hangers I think.
Not sure but he may have also been referring to joist hangers in tension? Which is part of the reason full-shank hanger nails are made, and why they’re galvanized for more than rust protection. Roofing nails, box nails, and “sinkers” don’t qualify.

FWIW “bending over the top” is neither fine nor overkill. I guess one could use a 2x8/10 hanger for a 2x6 and “create” a top mount, but that probably won’t increase their rating due to not being the same gage as a lot of top mounts.
Top-mount hangers are made to provide a higher load rating and are specified in some commercial applications for common lumber but usually for engineered beams or I-joists- often because engineered wood is designed to a higher load L/ and often much lower intended deflection characteristic per psf and length, plus top mounts afford a degree of tension resistance due to the double shear design that factors into some specified installations.
 
I’m in the process of putting up a similar structure for a carport. Here in Australia, PV panels are much cheaper than traditional roof cladding. I am planning to glue the panels together with sikaflex.
 
How would you do the beams, two side-by-side like he did or a 4" wide or something else?
If you look at the picture the inside beams butt the post and the outer one runs through out and is bolted to the post -- therefore you really only have a single beam at the stress points and all your load is on your bolts -- I would at least notch the post for the inside beam and run the outer beam through in one piece --- since this is a building with metal on the walls wood post would be fine and much easier to work with -- now if you went back and welded some angle iron under the stress points of the beam that would work to
 
I’m in the process of putting up a similar structure for a carport. Here in Australia, PV panels are much cheaper than traditional roof cladding. I am planning to glue the panels together with sikaflex.
Aluminium tee strips over and between the joints may be of interest-
thickly applied sikaflex as the expansion joint

 
can never understand the logic of putting the beams on the side of the post --it's much better to have your beans sitting on top of a saddle welded to the post
You make good points but the structure is weaker than even this.
If the carrying member hardware shear strength exceeds the sum psf of the dead and live load that’s perhaps acceptable. Maybe not best practice but at the same time there’s pole barns around here with nailed top beams on the sides of posts… been up 50 or 100 years lol. Also, a given nail has a shear and tension rating (16d I think is like 320#?)
The wood should be strong enough, barring snow loads.
But I don't love using nails to support the weight.

Looking at the pic what bothers me is there is essentially no provision for uplift resistance; worse, what is the torsional rigidity of 29- or 31-gage panels on a sidewall with no purlins or bracing?

No wind resistance and maybe only structurally sound in the vertical dimension only. Put 24” of snow overnight and a gusty 35mph wind- then what happens?! It becomes a flat ground mount
 
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