Exterior Insulation Options

There are so many exterior insulation options that it can be quite difficult to decide which one is the best for your own unique circumstances. We’ve given a lot of thought to what insulation we are going to use on the exterior of our shipping container house. In the process, we’ve had a good think about the pros and cons of each product.

Some of the most common exterior insulation options available in South Africa, that you may wish to use on your own project are as follows:

• Aerolite; also known as “Think Pink”
• Isotherm; an awesome recycled product
• Isoboard; a very impressive and useful product with a few uses
• Foil insulation; such as Sisalation
• Alububble; you may be surprised to learn you’ve probably seen a product similar to Alububble.

Aerolite / Think Pink

Aerolite, or Think Pink, needs no introduction to South Africans. Everyone knows about this product and many people have it installed in their ceiling cavities. Aerolite is a glass wool product and one of the oldest insulation products on the market (if not the oldest product).

Pros: Easy to obtain. Most people have worked with it before so know what to expect. It is very effective at not only keeping temperatures regulated but also for sound dampening. One of the biggest selling points of Aerolite is that it is non-combustible.

Cons: This glass wool product can make you itch if you don’t take the necessary precautions when installing it. If you want to use Think Pink for your exterior insulation option, battens would need to be installed on the outside of the house so that the product would have something to rest on and your covering boards have something firm to attach to.

Isotherm

Isotherm is similar to Aerolite, but is made from recycled PET bottles. It’s a good eco-friendly option as it uses something that would otherwise fill up our landfills.

Pros: Generally a little cheaper than Aerolite. Also a good sound dampening product. Won’t make you itch!

Cons: This product soaks up water like a sponge, so care would need to be taken to ensure that cavity is water tight. The weight of the water would pull down the Isotherm, thereby creating gaps in the insulation; something you don’t want! As with the Aerolite, battens would need to be installed for the outer panels.

Isoboard

We had the opportunity to see the Isoboard products up close at an expo a while ago. In a perfect world, this would be Kevin’s insulation choice. It is however, quite expensive.

Pros: This product is sold in boards, making it easy to cut and install. It doesn’t soak up water. It is mold resistant and lightweight. For internal applications it also comes moulded for ceiling boards.

Cons: Not the cheapest product out there. (We can’t think of any other cons. Kevin likes this product very much!)

Foil Insulation

It is strange to think that something that looks like a giant roll of tin foil can work as an effective insulation. In South Africa, there are a few brands of this product available, such as Sisalation and Envirotuff 202FR (FR stands for “fire retardant”). These products are foil, plastic and mesh sandwiches, developed as a cost effective insulation option. The reflective surface radiates heat away from the house.

Pros: Easy to install. Tape it to the side of the container and fit your cladding over it. It works as a rudimentary moisture and thermal barrier.

Cons: Does not work as a sound barrier. Not as effective as a thermal insulator as some other products, but does assist in regulating your internal temperatures. Tears easily so some care must be taken when fitting.

Alububble

Have you seen those car sun screens people use in summer – the ones that look like they are made from tin foil bubblewrap? Well, that’s essentially what Alububble is. The air pockets between the foil helps regulate the temperature a little more effectively than the foil insulation sandwich.

Pros: More effective than foil insulation. Easy to install. Doesn’t tear as easily as foil insulation.

Cons: More expensive. Still not the most effective product out there.

Of course, there are other options out there such as melthoid or spray-on insulation, but the above are the options we gave the most consideration for our project.

Our Choice in Exterior Insulation Options

Kevin informed me that in a perfect world, we would be using the Isoboard because it is easy to install, sound dampening, insulating and works as a moisture barrier. His second choice would be to use a combination of the Isotherm with a foil insulation. This would achieve the same result as the Isoboard, but with more work. Between these two options, the price would be similar. So, obviously, the best choice would be Isoboard.

However, Isoboard is above our budget, so we are going with a foil insulation, the Envirotuff 202FR to be exact, for the exterior, which will help with temperature regulation and work as a moisture barrier. The fibre cement boards that we are cladding the house with, will protect the foil insulation from sun and wind. The foil insulation turn will protect the metal containers from condensation and rain water that might be soaked up by the fibre cement boards.

As for sound dampening, we will cover that aspect when we do the interior cladding. But that’s a post for another day!

Don’t forget to leave a comment on your experiences with insulation. We would love to hear from you.