Panels as Sheathing?

I've been doing some research into my ADD/ADHD, and the term "hyper focus" has come up a few times. This next idea, is most definitely that.

It's quite, quite, outside the box, but i've had a pallet of Silfab B-Grade panels sitting around for about 6 months outside. I sold 4, so I have 17 remaining, between 265 and 300 watt. I'm doing a Grid-Tie on my home, and it's looking like these panels are just going to complicate the install where they're B-Grade, and i'm best to just leave them Off-Grid. I've also been wanting a storage area, and don't want to spend a ton on supplies, and mounting equipment for the panels. The building doesn't even have to be overly water tight to be honest, just something to put the 4-wheeler and Sea-doo under cover somewhat. Potentially throw a Gro-watt AIO that can take a large series string, then try and power a Mini split from it with assistance from the grid when my 5 kw lifepo4 monstrosity of a battery depletes.

That being said.......What if........hear me out............the panels acted as the sheathing on the front and roof on a small barn? If the frame was standard 2x4 construction, some extra diagonal bracing on the inside of the structure to take the side to side stress, and have the panels themselves as the exterior layer? They're taking the brunt of the UV damage regardless, and if the interior bracing is doing it's job, I can't see them adding much stress to the panel frames.

I'm thinking around 12' wide, then I could have 2 horizontal panels, a large door then 2 more horizontal panels across the front. Shed roof for the top, maybe put a dozen up there as well. Sheath the other sides in with boards, in my area I'm able to do a 600 sq ft building without an inspection. Still have to get a permit, but no one to poke around and see what's going on after that point.

I'm already past the point of realizing I'm crazy, but I might just try it anyways. And I know i'm only out the sheathing costs for one south facing wall and roof, but I figure it's still more sturdy than a tarp shed or those terrible metal sheds from Home Depot. They shouldn't even be allowed to sell them in our climate zone, they crumple after the first snow or any substantial wind.

Welcome to any criticism at this point, gotta feeling i'll be getting some flack on this one. lol. :D

It may simplify things if I consider this a Solar Pergola, with the potential to "close it in" during winter. Go with more of a post and Beam design, focus the panels moreso on the roof itself.

jgriffin:

This idea is nothing new, and I'd never label it " quite, quite outside the box". Glass, in many forms has been used to semi-enclose space, serve as a barrier, or even a piece of art. It was even used in that same basic form to create carports. But back then, it was not a solar panel due to that industry being in its infancy. There are bus stops that are made of solar panels to protect riders while they wait, and at the same time generate power. That being said, why not do this? Panels are cheap, they are pretty sturdy, and they might serve an additional purpose by generating some power. I have some friends who use solar panels in their business as tables, cubicle dividers, hallway screens, etc. Personally, I wouldn't go to the trouble to build something, and cut corners by not making it water-tight. With the price and scarcity of materials today, that wouldn't make sense in my way of thinking.

If you take some time, and shop around for some aluminum extrusions, you could fairly easily fab up a system to slide the panels into a rail, and seal them up so very little water gets in there. You might also consider making a entire wall of aluminum/glass. People who build aluminum or steel storefronts, windows, doorways, etc have tons of scrap aluminum, and you might score some when a remodel is being done. Like the kind they fix big thermo-panes into for glass fronts. Take some time, and make yourself a proper wall. Then make some power, and kick back and admire your work.

Have at it.

Good Points, SolarPrep!

I do have a heated garage space, as well as a baby barn already. The roof space over the garage is south facing, and initially was going to be where the panels would be mounted. However, my grid-tie system will be going there instead. Baby barn roof is behind the house, and is blocked by it a good part of the day. So I don't totally need the storage, but also, why not?

I've never used Uni-Strut before, but have seen others use it, kinda peaks my interest. Standard 2x4 Construction, with Uni-Strut run across so panels can slide in. Maybe some rubber T-Strip could be pressed down between them, and overlap the frames on both panels. Like you say, not much more effort to close it up properly.

Probably not a heck of a lot more effort than constructing a ground mount on the cheap honestly. I can see less posts in the ground being an immediate advantage where i'm into some pretty good ledge about 2' down in most places.

I honestly should give it a try. Thanks for your input!

Panels mounted to 3/16" by 1-1/2" steel angle with self drilling bolts. Glass sealed to frames, frames sealed together. No leaks. Cheaper than plywood!

jgriffin said:

It may simplify things if I consider this a Solar Pergola, with the potential to "close it in" during winter. Go with more of a post and Beam design, focus the panels moreso on the roof itself.

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do it, solar panels are getting cheaper and long lived then most other roofing material per sqft / square meter. Even when they stop producing - you still got a roof.

I'm currently planning a Solar Carport - with the recent rise in building materials - it makes using solar panels as primary roofing material.

You have to think about expansion and contraction of the Solar panels. One of the reasons, mounting racks are made out of aluminum - is because the panels are made out aluminum frames. So there need to be gaps between the panels which you have to fill in with something - to get a weathertight - flexible seal, which can take the movement of the panels without interfering or loosing up.
I haven't found a material for this detail yet.

Mixing dissimilar metals aluminum and steel creates electrolysis which causes the corrosion of the aluminum frames on the solar panels which is sped up by moisture. If you are going to do this use aluminum for framing with stainless steel hardware or find a way to isolate the two metals from touching each other which can happen even through the fasteners. Another thing is pressure treated wood has copper in it and that also will cause electrolysis.

Weldman said:

if you are going to do this use aluminum for framing with stainless steel hardware or find a way to isolate the two metals from touching each other which can happen even through the fasteners.

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While Galvanic corrosion is a thing (which can be minimized with Teflon washers) between stainless and aluminum. Both a fairly close together on the chemical ladder. So it's a fairly slow process when you don't get close to saltwater (coast) or salt on roads

There is stainless steel hardware which is developed for mounting solar arrays - it's probably a mix or coating on that to prevent corrosion (or at least slow it down that the 25 year design span is not impacted.
Every metal corrodes, just a matter how fast.

If you want to seal the panels you wouldn't want to put sealant on the flat side of the perimeter as you'd never get a single panel out. Cutting strips of Eternabond would waterproof the joint but allow you to cut it with a knife and lift a panel out if you needed to replace one

shadowsteve said:

If you want to seal the panels you wouldn't want to put sealant on the flat side of the perimeter as you'd never get a single panel out. Cutting strips of Eternabond would waterproof the joint but allow you to cut it with a knife and lift a panel out if you needed to replace one

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that's a great idea - I used Eternabond on my RV multiple times and it's awesome stuff. That would also permit a gap between the panels, and is flexible.

Downside is that eternabond oozes glue out to the sides. Not much, but over the years there is some significant dirt build up.

Once, I was thinking about aluminum HVAC tape, I've used it successful in metal roofing repair - but I fear that it's ripped apart when wind is going through the gaps between the panels.

Being surrounded by the ocean, we tend to change out our crimped Copper to Aluminum connections within a 5-7 year period on Home services. To the point we really only crimp aluminum to aluminum connections now. Anything mixed gets a Bolt On Connector. Galvanic corrosion is very much a thing here. Good points everyone!

eXodus said:

that's a great idea - I used Eternabond on my RV multiple times and it's awesome stuff. That would also permit a gap between the panels, and is flexible.

Downside is that eternabond oozes glue out to the sides. Not much, but over the years there is some significant dirt build up.

Once, I was thinking about aluminum HVAC tape, I've used it successful in metal roofing repair - but I fear that it's ripped apart when wind is going through the gaps between the panels.

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Aluminum tape will tear and split with any slight movement of the panels. The edge of Eternabond does have a bit of adhesive that bleeds out but I wouldn't think you'd get that much dirt attached to it unless you live in a dust bowl. Maybe prestick some nice white sand to it

shadowsteve said:

dirt attached to it unless you live in a dust bowl.

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I live in Florida, quarter of the year are hurricane style monsoon rainfalls and the other half year is dusty as heck. Really makes never sense cleaning my car it's either muddy or dusty.

The nice thing is - it rains so hard here over the summer that the solar panels on the roof are always very clean. It slowly dusts up over the dry seasons and then the summer rains wash everything away.

For additional strength I edge-bolted the HQST panels together on my bouncy golf cart. Applying gasketing and/or calking with the bolts should do a decent job of water sealing.

Also 3M VHB tape is really strong as it was designed for bonding aircraft skin. You will never get the panels apart. Grainger.

2.4 kw solar canopy, panels bolted to 2"x4" 6061 aluminum extruded box tube, and that's bolted to a 304 SS frame. 10 years and still good...SS bolts, no insulators.

eXodus said:

While Galvanic corrosion is a thing (which can be minimized with Teflon washers) between stainless and aluminum. Both a fairly close together on the chemical ladder. So it's a fairly slow process when you don't get close to saltwater (coast) or salt on roads

There is stainless steel hardware which is developed for mounting solar arrays - it's probably a mix or coating on that to prevent corrosion (or at least slow it down that the 25 year design span is not impacted.
Every metal corrodes, just a matter how fast.

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Stainless and aluminum are actually almost polar opposites on the galvanic chart my friend.

They're among the worst two materials to put together, as far as commonly used ones go.

Note the location of 300 series that most people use, but even still the 400 series is pretty far away.

Crisp said:

2.4 kw solar canopy, panels bolted to 2"x4" 6061 aluminum extruded box tube, and that's bolted to a 304 SS frame. 10 years and still good...SS bolts, no insulators.

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Good galvanic bonding can help greatly with the situation, which I believe is standard practice with marine environments and I assume you've done.

Weldman said:

" ... pressure treated wood has copper in it and that also will cause electrolysis. ... "

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This is a big issue when someone uses treated lumber for the trailer bunks on their aluminum boat. The new compounds used to treat wood will eventually eat right through the bottom of the boat. " ... When using the new Pressure-treated wood – ACQ and CA, keep in mind that they do have a higher concentration of copper, which results in a chemical reaction that discolours and corrodes aluminum and some metal fasteners. ... "

Steel and aluminum do not mix all that well. On my Honda crf450r, I use anitsieze on all the steel bolts that thread into the aluminum frame in order to halt corrosion, and eventual seizing of bolts.

This is from the signaturesolar website solar shed . They recommend calk between the panels to create a watertight roof. The article also mentions screwing the aluminum frames directly to the treated lumber. I would do something to keep the two apart.

Kornbread said:

When using the new Pressure-treated wood – ACQ and CA, keep in mind that they do have a higher concentration of copper, which results in a chemical reaction that discolours and corrodes aluminum and some metal fasteners

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It’s the acidic action of the treatment agents that is the major problem with pressure treated wood, not the copper.

CCA plywood in aluminum boats, for example, never caused short-term issues, nor did it create failures of fasteners with high rise building balconies or the semi truck aluminum trailers that delivered from the plants to the yards of retailers and distributors.

Aluminum and stainless DOES make for bad juju, but for whatever reason it seems to go years without issue in boats, especially when painted. I don’t know why because on paper: it shouldn’t.

I am thinking the same thing when putting up the next building for my lifestock. I will need power for them - might as well put panels up as the roof.

12VoltInstalls said:

It’s the acidic action of the treatment agents that is the major problem with pressure treated wood, not the copper.

CCA plywood in aluminum boats, for example, never caused short-term issues, nor did it create failures of fasteners with high rise building balconies or the semi truck aluminum trailers that delivered from the plants to the yards of retailers and distributors.

Aluminum and stainless DOES make for bad juju, but for whatever reason it seems to go years without issue in boats, especially when painted. I don’t know why because on paper: it shouldn’t.

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I should have included the link in the quote concerning cca/ca and copper being the culprit as I do not know if this is the reason, or the sole reason for the increased reactivity vs older treated lumber. A quick search says " ... chemicals used to treat this wood were revised in 2003 to remove some of the potentially harmful elements in the treatment. The change in chemical formulations increased the corrosivity of the wood when in contact with metal parts. The two most popular chemicals for wood pressure treatment are alkaline copper quaternary (ACQ) and copper azole (CA), which are both active corrosion materials. ... " American Galvinizers Association I do use special fasteners when building decks with treated lumber.

Thinking out loud ...
I have only used marine grade plywood in boats. The main difference between marine grade and 'reg' grade is in the glue. AFAIK, it is not treated, although, if using treated wood, it would stand to reason that a nonporous painted surface between the differing materials, might, mitigate a reaction. Curious, do you know which wood treatment method was used in the applications you mention?

... and with a bit more research, it appears not all treated lumber is cca/ca and may actually be aluminum friendly.

Back to the OP and mounting panel sheathing directly to what is basically a pole barn. The OP may be able to source the aluminum friendly lumber, or possibly a simple barrier of paint between the panel's frame and lumber might suffice. It would be interesting to know the long term outcome.

This thread is very interesting as I do plane on a shop building. In my case, panels would not be ideal for the main roof, but a 'lean-to' to shelter the cars, tractor, boat, etc., would be a most excellent idea.

Kornbread said:

The main difference between marine grade and 'reg' grade is in the glue. AFAIK, it is not treated,

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No.

ACX is indicative of exterior glue in the laminations with the X. Marine plywood = same glue.

The main difference between marine and ACX fir plywood is that the marine plywood laminations contain no voids, and surface ‘footballs’ are not allowed due to the fact that marine plywood cannot have stress risers where it could fail as it is molded or formed to the continuously varying shape of a boat hull.

Marine plywood is for boat hulls.

12VoltInstalls said:

Aluminum and stainless DOES make for bad juju,

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Short_Shot said:

Stainless and aluminum are actually almost polar opposites on the galvanic chart my friend.

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neither aluminum nor stainless are used pure in modern products. Usually they are alloys mixed with something else.

That's why in practical applications it is very common to have stainless steel fasteners in Aluminum. Usually those bolts and nuts are a special kind of stainless which is more compatible with the aluminum used in solar applications. BUT! there are usually not bolts threaded directly into Alu

You got a stainless nut and bolt clamping an aluminum member.

eXodus said:

neither aluminum nor stainless are used pure in modern products. Usually they are alloys mixed with something else.

That's why in practical applications it is very common to have stainless steel fasteners in Aluminum. Usually those bolts and nuts are a special kind of stainless which is more compatible with the aluminum used in solar applications. BUT! there are usually not bolts threaded directly into Alu

You got a stainless nut and bolt clamping an aluminum member.

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Well that's not really true. The chart clearly shows alloys of both and where they typically lie. There's no such thing as "pure stainless steel" either. All SS is an alloy, and the pointed out spot on the chart IS "aluminum alloys". Facts is facts.

HOW its fastened plays a part in reducing it, but it doesn't change the matter. The reason most people get away with it is that the aluminum oxide has a different value from the aluminum itself... which gets to your point about threading vs nuts/bolts. You are right that threading right into the aluminum is worse though for sure. That's where most of the corrosion I find at work starts, until the whole aluminum part is rotted away.

I still use stainless and aluminum myself, but only when its not going to be exposed to saltwater from roads and such. I have had many examples of aluminum stuff and stainless fasteners rotting out at work where we use bromine salt at a really low dilution rate (much lower than rain/road salt) after only a few years of use.