Mobile frames for Roof. I probably need some hints.

[WoodsieLord]

Hello everyone,

After almost a year working with my electrical installation, UPS, battery bank, and DIY battery monitor and such, I'm close to the last phase of the project: Putting the panels in place.

I have a few constraints that I want to state before going into further detail:
- The roof is flat, with membrane. It's actually the 10th story of a building.
- There are no fall protections. Borders are 20~25cm (8~10 inches) tall just to guide rainwater to drains. I climb there pretty often and I'm used to the lack of walls: I play safe, I stay far from the dangerous edges.
- I don't want to bolt structures to the roof. I'm planning to use dead weight to help against winds.
- I'm willing to add one or two "guy wires" (funniest name. ever.) that I could bolt up to two walls, whose edges are safe to approach.


Well, that being said, the vanilla constraints are as follows:
- 4 Panels, 2m x 1m (~40 by 80 inches) each.
- I want to be able to tilt them up to ~50 degrees.


My current "most appealing idea" is making a cubic (parallelepiped? I think) iron frame that would sit on the roof surface stuffed with water filled soda bottles as dead weight. On top of the structure, I would fix a flat frame that would hold tight a single panel while pivoting (using hinges) in a single axis to achieve the desired angle (upt to 54º would be ideal).
+Benefits: Such structures would be fairly easy to transport/move to another location. I don't need to build them on the roof itself! I could work in a safer environment then move them to their position, and finally add the dead weight.
-Downsides: I need to build four of them for my current test setup. I would need to build two more (when AND if I get to buy two additional pylons--Sorry!, panels). Fixing many structures in place with "guy wires" is way harder than fixing only one.


What do you think? Do you have a better idea to improvise panel mounts without bolting or damaging the flat surface?
Thanks a lot for reading! I know I have a tendency to write a lot and my english is not pretty.

PD: I posted int his subforum, because I think my project is absolutely unconventional, fairly unsafe, has a "long term test" nature that does not comply with common standards. Sorry if this is not uncommon or vanilla...!

 

[ghostwriter66]

Can only answer one of your questions -- BUT Water bottles will freeze and crack in the winter ... and the remainder of the year will be hit with constant UV and will start to crack and leak so not a good idea ... I recommend cinder or cement blocks or heavier "pavement" tiles ...

 

[JoeHam]

I would suggest looking at the mounts for RV's all over youtube. These people mount on membrane roofs and then drive 75mph with them!

Look for RV solar and VHB tape on youtube to get some ideas. Then analyze the good/bad/ugly of those ideas here before you implement them.

 

[WoodsieLord]

Can only answer one of your questions -- BUT Water bottles will freeze and crack in the winter ... and the remainder of the year will be hit with constant UV and will start to crack and leak so not a good idea ... I recommend cinder or cement blocks or heavier "pavement" tiles ...

I thought of UV, I was thinking of shielding the lower section from the sun. Thankfully, weather here is usually between 5ºC and 35ºC, no freezing temps.
I live in Buenos Aires, Argentina

 

[WoodsieLord]

I would suggest looking at the mounts for RV's all over youtube. These people mount on membrane roofs and then drive 75mph with them!

Look for RV solar and VHB tape on youtube to get some ideas. Then analyze the good/bad/ugly of those ideas here before you implement them.

Thanks!, I will check those. I'm trying to avoid fixing anything to the roof, so once I decide to remove the panels in a future the roof would remain untouched without any disturbances. I will have to get creative to avoid this issue...!

 

[ghostwriter66]

Thanks!, I will check those. I'm trying to avoid fixing anything to the roof, so once I decide to remove the panels in a future the roof would remain untouched without any disturbances. I will have to get creative to avoid this issue...!

VHB tape will definitely leave a residue ... I would just make me 2 rectangle frames out of PVC pipe and connect them together with about 2 inches of pipe in between them for circulation and mount the antenna to the top and lay the bricks or blocks or even sandbags on the bottom pipes ... (does that make sense??)

 

[Keith C]

Think UV in all regards. PVC will fail in the sun in about 2 years. Unless, you block the UV by painting it.

 

[EllaBella]

If you can get away with drilling a few sneaky holes you can put some expansion bolts with eyelet to anchor from, it would be far more secure. Solar panels definitely catch the wind like a sail and if not secured properly will fly off.

I don't use them to anchor my solar they're bolted to the roof, mine are for accessing the roof, but it would work to anchor panels with steel cables.

I have drilled several 10mm holes in the bricks of our house so I can attach a safety line to multiple anchor bolts while I'm up on the roof. I just pop my climbing harness on, clip carabiners and slings to the anchors and then clip the slings to a single carabiner to put my rope through. It's saved me a few times as ladder access isn't an option for most parts of our roof. (I don't recommend this, the anchors are not load rated and it is a risk, but better than nothing)

Another option could be climbing ballast/weight bags, the have rated load attachment points on them to secure safely too, we use them as ground anchor points when there's a weight difference between the climber and the belayer. You just fill them up with sand or gravel, then clip a carabiner through the loops.



They're safer as you can tie to the loops, so if the panels move in wind the weight move with it, if you use cement blocks just laid on top of the frame there's still a chance the panels could come loose, unless you put anchor bolts into the concrete blocks.


In regards to building a frame, you could use t-slot aluminum extrusion, would be a easy and light weight way to build a frame for solar.

 

[WoodsieLord]

Update:
I made an iron frame with bolts and nuts that weights ~45kg (~100lb). Each panel is ~20Kg, so the whole thing is around 125Kg (~275).
I made three anchor points to the tiny walls and for now I will leave the panels absolutely horizontal (they should be 54º in winter, so this is going to hurt efficiency badly).
Past Monday we had a storm that had wind gusts of 70km/h (~43 mph). The structure held quite well. Yet I wouldn't risk rising them to angle without bolting the structure waaay further.

Thanks everyone!