How to Insulate Your Shipping Container Home with Spray Foam Insulation
For much of the world, the weather is turning colder by the day. If you’re considering building a shipping container home or are in the process of designing one, you may have considered whether or not you want to insulate your home. Let me save you the mental energy—you do! Even if you live in a moderate climate, insulation is just as important for a shipping container house as it is for any other home. It’s not just about keeping hot or cold weather out; it’s also about keeping heat and cool in and saving on your energy costs and preventing corrosion and mold. It may seem like an unnecessary expense up front, but it will be more cost-effective in the long run.
So please, please insulate your shipping container home. As we discussed in the post How to Keep Your Shipping Container Home Warm In the Winter, there are a number of ways of doing so. We go through many of those methods in aforementioned post but, for now, we’d like to focus on our preferred method of insulation: spray foam.
Why We Prefer Spray Foam Insulation
Spray foam insulation is the quickest means of insulating your home. Even better, it gives your house the highest R rating (the R Rating relates to how well the insulation blocks heat flow; higher numbers mean greater resistance). It provides your cargo container house a seamless, tight layer of insulation and provides a great defense against condensation, corrosion, and mold. It’s very flexible and can conform to any size or shape space. You don’t have to worry about gaps or leaks or uneven coverage. You can apply it as thickly or thickly as you like, and it adheres very well. You can spray it on the external walls of your shipping container home, on the interior walls, and even underneath.
There are two types of spray-on foam: “open-cell” and “closed-cell.” The difference between the two types is the R-factor, the density, the strength, the waterproofing, and the price. Closed cell foam is more dense, more rigid, and resists air and water better.
That’s not to say that spray foam insulation is perfect. It tends to be more expensive than other methods of insulation. It can also be very messy to apply. We’ve ruined countless pieces of clothing and shoes during application. If you’re not familiar with spray foam, we’d recommend hiring a pro.
How to Apply
You can apply spray foam insulation with framing or not. If you’re framing interior walls anyway, you might as well put insulation inside the frames while you’re at it. You can then trim off any excess and cover the walls with your choice of materials. You can also insulate your floor by framing the floor with wood, spraying the foam, trimming the excess, and covering with plywood and/or your chosen flooring material.
In terms of technique, there’s not one right way to apply spray foam. Check out this video and this video to get an idea. Stand about 30 inches away from the wall you’re spraying. We prefer applying by spraying in horizontal lines, as this seems to produce fewer pass lines. We overlap our passes a good deal (3/4 overlap) and try to get everything as flat as possible. If things start to look bumpy or uneven, trying speeding up your hand movements.
It’s easiest to do this when it’s not cold out. Cold metal can be difficult to spray directly on to. If you must apply directly to the metal when it’s cold, try to do so when the sun is out and has warmed the metal as much as possible.
As noted above, you can also apply spray foam to the outside of your shipping container house. Read this article for the how and why of this method.
Which spray foam should you use? We recommend Foam it 602 Class 1 Spray Foam Insulation Kit. Whichever spray foam solution you choose, though, make sure it’s closed cell polyurethane foam.
How do you plan to insulate your shipping container home? Or, if it’s already insulated, what method did you use? Comment below!