Metal Building Insulation - How To Insulate a Barn, Shed, or Garage
No Need for "Traditional" Insulation
On a non-conditioned building (like most sheds, barns, and garages), there really is nothing better than a radiant barrier to control the heat gain. Structures like that don't reply on continuous cooling or heating 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 insulation is not necessary because this building isn't trying to keep a constant temp. The goal is NOT to make the structure airtight in order to keep cold (or hot) air inside of it; the building is vented, so it can’t be airtight. 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). The goal is to get the building as close to ambient as possible. 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.
The main problem with heat gain in a metal building is that the exterior metal 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; foil insulation 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.
What Product Should You Use?
For a basic install, you just need radiant barrier alone.
However, if your building has issues with condensation, you should consider upgrading to one of our BlueTex foil + foam products. Learn more about how to control/eliminate moisture in your metal building here: BlueTex Insulation Moisture Guide
How to Install
Ceiling/Roof: 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 of the continual heat gain in the hot months, and to help temper the chill in the colder months.
*62" BlueTex™ Pro shown above*
Like most installs of this nature, getting the BlueTex™ closest to the roof line will bring about the best overall results, specifically for hot climates. If you’re doing new construction, the video above will give you some good ideas of how to approach that. If you are retrofitting an existing structure, then you have a couple of options, depending on what the structure is made of.
Simply put – get your layer of foil somewhere below the roof line but above the work space. The foil will will work so that most of the heat that would normally come off the building into the space below the roof line will instead be reflected back out because of the BlueTex™. Remember to leave some gaps or breaks in the install so that airflow can still move around the area as if the foil wasn’t there. More info on proper ventilation here: The Basics of Ventilation in Non-Conditioned Buildings.
Walls: If you install the foil on walls catching direct sunlight, it is best to have the foil closest to the outside layer as possible, while still maintaining an air space on one side of the foil. This way it will block the heat at the entry point, rather than letting it travel through all the siding materials. Unfortunately, there are so many different type of construction methods, we cannot cover every type of building type, so you might have to get creative on how to install the BlueTex™. We're here to help if you need some ideas!
How to Install in a Conditioned Barn or Shed
The main thing is to get a piece of BlueTex™ between the walls, ceilings and YOU! We help customers everyday with their particular buildings and applications. Remember, as long as you can achieve the air gap on at least one side of the foil, it WILL work.
Goal: Get the foil on the outside of the thermal envelope (the area being conditioned). It really belongs outside the thermal envelope; if your space will be heated and cooled, the layer of radiant barrier closest to the outside will block the bulk of that heat from getting into the wall cavities and roofline. Then you can proceed with installing traditional insulation and then drywall/sheet rock to finish it out. Simply put, your layers will look similar to this:
- Roof deck/Exterior Sheathing
- Air gap (created by foam strips or purlins)
- Radiant Barrier Foil layer
- Batt Insulation/foam board/spray foam/some other r-value
OR if you are mainly looking to get better heat retention (i.e. in a cold climate), then layer your cavities like this:
- Roof Deck/Exterior sheathing
- Insulation/foam board/spray foam/some other r-value
- Radiant Barrier Foil layer
- Furring Strips (horizontally across studs) for the air gap
Whichever your situation may be, a conditioned or non-conditioned metal structure, the bottom line is this: adding a radiant barrier is the biggest improvement you can make, for the smallest initial investment. A single layer, installed closest to the outside, is going to result in a more comfortable structure and a more efficient building.