Rising energy costs are just one of the motivating factors that have builders implementing exterior insulation in the homes they’re building. Builders are always looking for ways to improve the way they insulate homes. Exterior insulation helps to control moisture on the outside and brings homes’ insulation performance well beyond current building codes. This brings a lot of value to the house when compared to only cavity-based insulation. In many climate zones, it has even become code to add exterior insulation to new builds.
The use of rigid foam insulation boards for exterior insulation has been the pick for many years. But another product has been on the rise, proving to be even more efficient, with even more benefits – Rockwool, or mineral wool.
With many exterior insulation options, how do you decide what’s right for a project?
Let’s compare traditional rigid foam insulation to another, less-mentioned product, mineral wool.
Rigid Foam Insulation
Rigid foam insulation has become quite popular among builders who choose to utilize exterior insulation. It cuts easily and is attached over the weather resistant barrier to the sheathing. Its air barrier, R-value, and size varieties have contributed to its rise in popularity. Polyiso has been said to possess one of the highest R-values of any insulation, but we’ll look at this in more detail below. Finally, a number of these products include a foil radiant barrier, which is popular in the hotter climates.
Mineral Wool Insulation
Rockwool, or mineral wool, insulation is a form of insulation made of rocks. The insulation is comprised of 40% recycled materials and contains no blowing agents or CFCs (so nothing to off-gas). This very “green” product comes along with many benefits, which I’ll share below, and comes in easy-to-use batts that can be easily attached to the sheathing.
While the argument can be made for either insulation choice, I’ll give you eight reasons to opt for Rockwool instead of Polyiso for exterior insulation.
Depending on your project, insulation needs vary, but exterior insulation is becoming not just the norm but also a necessity. If you’re going to blanket a house, do it with a product made from recycled materials that will add a new level of efficiency to your home.