Goal Temps in Non-Conditioned Buildings
The main problem with heat gain in a metal building is that it will absorb so much radiant heat that the inside temperatures will far exceed the outside temperatures. The simple solution to this is a radiant barrier; it will essentially act like shade. Reflecting 97% of that radiant heat out of the structure is the key to a comfortable space, even without conditioning it.
We have many customers who have used radiant barrier on garages, barns, carports, airplane hangars, work sheds, warehouses etc. with great results in comfort. It's important to remind yourself that structures under this category are just that: structures. This means they will not feel or operate like conditioned or living structures; they will be hotter/cooler than a home/office space and they'll also likely be wetter, and that's ok. That being said, the goal for these types of buildings is to take the edge off the continual heat gain in the hot months and to help temper the chill in the colder months.
No Need for Traditional Insulation
On a non-conditioned building, there really is nothing better than a radiant barrier to control the heat gain. Structures like sheds, carports and barns can all benefit greatly by adding a layer of radiant barrier near the roof line and any sun-catching walls to keep the heat out. On a non-conditioned building, traditional r-value insulation is not necessary since you're goal is NOT to keep conditioned air (cold or hot) inside of it, but rather just trying to keep it comfortable when in use. Therefore, the most realistic expectations you can have for a building that you are not heating or cooling, is to get it at (or close to), outside air temperature (also known as ambient air temperature). Getting the air temperature lowered is largely relative to the amount of ventilation you have going through the structure. However, keeping the inside of a metal structure at or near ambient temperature is practically impossible if you do not have a radiant barrier. The radiant barrier will work to reduce the surface temperatures, and the ventilation to help bring the air temperatures down.
How to Install
Like most installs of this nature, getting the BlueTex™ closest to the exterior of the building will bring about the best overall results, specifically for hot climates.
If you're doing new construction, you can wrap the outside of the frame with BlueTex™ too, just make sure the FOIL SIDE of the product has at least ¼" to ½" of an air space between it and the exterior/interior sheathing. You can see more info on how to install here: Install BlueTex™ in Your Metal Building
What About Moisture?
Interior moisture (condensation) is created when relatively warm-moist air hits a cold surface (usually the metal of the building). One of the biggest issues we hear of with metal buildings are customers trying to find a solution to "sweating buildings" and we get it! We've written an extensive guide to teach you (1) what causes moisture in your metal building and (2) how to stop it.
Did you know? The problem itself may be what you're using the building for! Livestock, agriculture products, grain etc. are all commonly stored inside barns and sheds. These items will produce high levels of moisture & sometimes there's not much you can do about that. The best way to protect yourself against moisture forming inside a structure like that is to have plenty of ventilation to keep moisture from sticking, and pair it with a radiant barrier to stop the huge swings in temperature inside the building.