Facts and Information

About Spray Foam Insulation

Spray foam insulation is a method of insulating and air-sealing using a spray application.

The foam sprays on as a liquid and then quickly expands to fill and seal the cavity or surface. As it expands, it seeps into all the nooks and crannies to form a continuous air barrier, keeping you cooler in the summer and warmer in the winter.

The American Chemistry Council defines spray foam as a continuous insulation and air seal plastic material that is sprayed on walls, roofs, into gaps and corners, and on all contoured surfaces. Spray foam is able to seal cracks and crevices throughout a home, reducing the air exchange, or air leaks, in and out of a home. Air leaks are a leading cause of increased energy bills. HVAC systems that heat and cool buildings are continuously operating. By reducing extreme temperature variations with spray foam insulation, you will save on the overuse of mechanical systems which leads to lower energy bills.

The Benefits of Spray Foam

Why Choose Spray Foam Insulation? Here are just a few benefits.

Save Money

Spray foam insulation installed by Envelope Group is a premium product that pays for itself quickly. You may be able to reduce the size of your heating and cooling equipment, saving installation or replacements costs.

Keep a Healthy Home

By air sealing your home, you can help block pollutants that can affect your health. Dust and dirt, mold and moisture, radon, exhaust fumes, and carbon monoxide are reduced to keep your home and air clean.

Comfortable Indoors

Create a cocoon effect by air sealing your home with spray foam insulation. Seal between heated/cooled living spaces and unconditioned spaces, to maintain even temperatures throughout your home.

Protect Your Home

Spray foam insulation can help your home last a long time. Some Spray Foam options can offer extra structural stability to your walls which can’t be achieved using traditional forms of insulation.

Open-Cell Vs Closed-Cell Spray Foam

When it comes to spray foam insulation, selecting the right product for the application is important. The advantages of open-cell foam compared to those of closed-cell foam can make a difference in how your home performs throughout the year.

The Similarities
Open-Cell Spray Foam
Closed-Cell Spray Foam

Similarities of Both Spray Foam Types:

Spray in to fill all gaps and holes
Form an air barrier to stop drafts and air leakage
Don’t provide a food source for mold (check with your spray foam manufacturer)
Don’t provide a food source for pests

Open-Cell Spray Foam

“Breathes” — it is vapor permeable and this can let your home dry out.
Moderate cost $ per square foot
Reduces sound transmission so you don’t hear from one room to the next
Flexible – moves with your house to ensure there are no gaps in your insulation and no loss of air seal
Doesn’t absorb water; lets it drain down through the insulation (check with your spray foam manufacturer)
Good thermal insulation – R-3.7 per inch thickness. A 3.5 inch thickness is suggested to get an air barrier

Closed-Cell Spray Foam

Doesn’t “Breathe” – acts as a vapor retarder
Higher cost $ per square foot in most applications
Lower sound reduction
Stays rigid – helps wall strength; impact resistant.
Doesn't let water in (check with your spray foam manufacturer) – this is an advantage in flood zones. Great for flood prone areas
Great thermal insulation – R-6.0 per inch thickness

The R-Value

When measuring the effectiveness of insulation, R-value measures the ability to limit conductive heat flow (heat transferred through it). But the primary method of heat transfer is not conductive heat flow — it’s air leakage (convection). Air leakage can account for up to 40% of a building’s energy loss, and it cannot be stopped with traditional insulation.

What Does R-Value Measure?
Sealing Air In Reduces Energy Costs
Higher R-Values Are Not Always Better

What Does R-Value Measure?

R-value only measures how well insulation resists heat movement through the insulation material (called conductive heat flow). It doesn’t take into account how well the material stops heat movement from convection, carried in the air. Air leakage can cause up to half of your home’s energy loss.

Sealing Air In Reduces Energy Costs

R-value doesn’t measure air flow through a material, so without air sealing your home could lose a lot of heated or cooled air. Spray foam insulation seals your home as well as providing an effective R-value.

Higher R-Values Are Not Always Better

Did you know 93% of conductive heat flow is already stopped by R-12 insulation? Upgrading from R-12 to R-40 reduces conductive heat flow by only another 5%. If you use very high R-value fiberglass or very high R-value cellulose, you may still get high heating and cooling costs. Spray foam insulation can provide a high enough R-value plus offering air sealing to maximize comfort and minimize your energy bills.

Spray Foam & Building Codes

When using spray foam insulation, you sometimes need to include other materials to meet code. Your builder or Envelope Group technician will check with the local code official to ensure that everything will meet their requirements.

Thermal Barriers
Ignition Barriers
Cold Climates: Vapor Barriers
Hot and Humid Climates: Vapor Barriers
Hot and Dry Climates: No Vapor Barrier

Thermal Barriers

If the spray foam insulation is used in any part of your home used as a living space, it should have a thermal barrier that has been tested and approved for use with the spray foam. Thermal barriers are designed to protect against direct fire damage to spray foam adjacent to living areas for at least 15 minutes. A thermal barrier might be a material such sheet rock, plywood or particleboard, or a painted-on fire proof coating.

Ignition Barriers

If the spray foam insulation is used in any unoccupied part of your home, such as an unoccupied attic or crawl space, it should have an ignition barrier that has been tested and approved for use with the spray foam. An ignition barrier is a fire protective coating designed to inhibit or prevent the start and spread of fire from a spark or direct heat on the spray foam surface. Ignition barriers are usually spray-on or brush-on coatings.

Cold Climates: Vapor Barriers

If you’re using an open-cell spray foam insulation in a cold climate, you’re usually required to have a vapor barrier or vapor diffusion retarder on the interior (warm in the winter) side of the insulation. This blocks moisture movement from inside your house to the outside, where it may condense and freeze. Vapor barriers / vapor diffusion retarders are typically membranes (plastic sheets) or brush-on coatings.

Closed-cell spray foam insulation typically doesn’t require a vapor barrier or vapor diffusion retarder.

Hot and Humid Climates: Vapor Barriers

If you’re using an open-cell spray foam insulation in a hot and humid climate you?re usually required to have a vapor barrier or vapor diffusion retarder on the exterior side of the insulation. This blocks moisture movement from outside your house to the inside, where it can cause mold and increase the amount of energy you need to cool your home. Vapor barriers / vapor diffusion retarders are typically membranes (plastic sheets) or brush-on coatings.