Interesting Metal Building Roof Idea? asking for input

[Ryan29]

So, I think I have an interesting idea on how to turn down the heat in my metal building 30'x24' shop.

First, it is constructed in, i don't know the style, not hipped but with smooth rounded corners at the top and where it turns down to the vertical wall. Hope that makes sense.


I live in Tulsa, OK, and heat has been a big problem now that I do more things in the shop.

No insulation, no trees to provide shade cover. Thought about growing something like A. Gigantea on trellis on the sides, but still doesn't help with the worst part, being the roof. Plus, don't want to deal with the hassle of maintaining the vines.

Heard about "Glass" paint, but still a couple years from commercialization. So I had an idea, why not just mount some metal panels on top of the building (leaving a 2 inch gap)? It'd cost me about $700 in materials, screws, boards etc to get it all set up. Think solar panels providing shade, but they're not solar panels But if it works as well as I think it will, it'd probably be worth it.

I cannot find a single example of this being put into practice, but sure seems like the best and "most instant" way to reduce heat in the summer, albeit a difficult endeavor.

yea or nay? reasons?

also, condensation, but that's another problem for another thread

 

[jkeyser14]

My two concerns would be snow loading bending the panels since they would be unsupported and wind getting under the panels and wanting to tear them off. Being in Tulsa you don't have snow, but you definitely have wind.

 

[GoodStuff]

Spray Foam... anything else is just a trial and error approach and will end up costing you the same

 

[Musicinabottle]

Insulation is made for that.........

 

[matt_i]

Directionally I think its correct, make another radiant-to-radiant transfer with a convection gap in between. If I ever worked out of a sea container I'd want a standalone metal over-roof for same reasons.

I think it will be difficult to get standoffs that don't leak and don't banana the upper panels if a strong wind is near and the full panel is engaged in pressure from uplift. (For example how to screw into the center of the panel in many places you may not be able to see) You may also find a rare bird you've never seen before make this 2" gap a perfect nesting area and attract a whole flock.

I would try something else first. When i was going to build a metal bldg I had ideas of making a roof misting system. (You can use PVC for this ) Basically the idea is to heavily mist the roof panels which leads to evaporative cooling that removes heat. Typically water used like this is pretty cheap as compared to electricity to drive the classic phase-change refrigeration loop. There is some reading on the above subject that I found (haven't checked in about 7 years now) but you could easily try some experiments with a garden hose or pressure washer fanning out the mist and do some trial and error about how often it needs to be refreshed and if it actually makes a difference in the shop temp before committing to the idea.

 

[MushCreek]

I once re-roofed our old house, building an entire roof structure over the existing one, which didn't have enough pitch. The effect on temperature was amazing (we were in FL). I can still remember cutting the ridge vents, and the sawdust was like a fountain, riding the rising hot air in between the two roofs. It dropped the attic temperature some 40 degrees on a hot day.