Don’t let yourself be fooled by the delicate feel of open-cell spray foam. Despite its more porous qualities, it actually seals very well. It does, however, let the moisture in the air come through it. That doesn’t mean it doesn’t have its useless though. Open-cell spray foam is perfect for the space inside walls and beneath the roof. It’s uses don’t end there though. Open-cell spray foam is a great alternative to closed-cell due to its very light weight. It can be used to cover much larger areas than closed-cell, and it can be used to create sound barriers. The same properties that make it so useful, however, are the same qualities that, in certain circumstances, can make it a lesser option than its competitor – the closed-cell.
The Sound Barrier
The delicate, airiness of open-cell spray foam tends to snap and split as the foam grows in size on its way to curing and hardening. In the same way that closed-cell insulation seals to create an air barrier, so does open-cell. They both may create a seal, but that seal has very different properties. Open-cell’s barrier, however, lets the water vapor in the air sneak through it. The great thing about open-cell is that, at only .4 to .5 lb. per cubic foot, the foam insulation places no burden on the loading bearing weight of the structure. In addition to its light weight, it’s also much friendlier for the environment, due to its using water to send the foam out. Open-cell insulation creates an excellent sound barrier. This can be used to your home’s benefit and seal off sounds between walls or rooms with little weight added to your home’s structure.
The Application Process
Two separate components are combined together to form open-cell spray foam. Due to its extraordinary light weight, it can be used to insulate large areas with far less foam than its closed cell cousin. In fact, it can cover almost three to four times as much space at the same weight. It is also notably less expensive. Manufacturers on both side of the fence have been pioneering new ways to make their foams more and more environment friendly. While some success has occurred, for now at least, the two foams stay roughly the same as they have been. Some foams highlight their natural ingredients, such as soy oil. These natural ingredients are, however, usually a very small part of the overall mix. The traditional components of spray foam make up a much larger part of the overall equation. Open-cell is typically considered more Earth-friendly because of its use of water to spray the foam. Water, of course, does not contribute to global warming. Closed-cell spray foam does not use water. Instead, it utilizes chemicals and toxins with a much higher global warming potential (GWP).
Pros of Open-Cell Foam
• Can insulate larger areas at lower weight.
• Price per R-value is cheaper than closed-cell foams.
• Seals an air barrier.
• Creates a sound barrier.
• Uses water as an eco-friendly alternative to chemicals.
Cons of Open-Cell Foam
• Lower R-Value makes it not a great solution for small areas.
• Contact with water could cause adverse effects.
• House may require a water vapor barrier or house wrap
• Open-Cell may go down in size over time and be less effective.