An important question to ask before getting the next utility bill is where exactly your home is losing the energy you’re paying for?
The answer, for most American homes built before 2000, is: everywhere. The U.S. Department of Energy estimates that air leakage accounts for 25 to 40% of the energy used for heating and cooling in a typical home.
That statistic is alarming because all that loss is attributed not to inadequate insulation thickness or inefficient appliances, but rather air leakage. Spray foam insulation is a great solution to this problem because it does two things simultaneously. It insulates and air-seals.
What most homeowners don’t fully understand is how many places in a house benefit from this. Here are all the areas of your home that can be insulated with spray foam.
What Areas Can Be Insulated With Spray Foam?
1. The Attic
Since heat rises to the top, all the heat generated by your heating system in the winter is trying to escape through the top of the building. In summer, solar energy absorbed by the roof surface radiates downward into the attic space.
Most insulation failures occur in the attic, and spray foam helps solve this issue.
The conventional attic floor approach insulates the horizontal plane between the living space and the attic. The attic itself remains unconditioned; this works well when executed correctly, but it has a fundamental limitation, which is that it leaves all the ductwork in the attic. Even the most well-insulated ducts can lose conditioned air through conduction in an extreme temperature attic.
Another approach is to spray foam at the roofline, which involves applying closed-cell or open-cell foam to the underside of the roof deck, creating what’s called a conditioned attic.
2. Rim Joists
If spray foam installers had to identify the single location where homeowners get the best return on the smallest amount of material, most would point to rim joists without hesitation.
If you’re not already aware, rim joists are the perimeter framing members at the top of the foundation wall where the floor system meets the exterior wall. The best material used here is closed-cell spray foam. A 2-inch application of closed-cell foam is usually applied directly to the rim joist, filling the cavity between the sill plate and the bottom of the floor and insulating to approximately R-13.
3. Crawl Spaces
For decades, the standard recommendation was to vent crawl spaces to the outside. The theory behind it was that ventilation would control moisture by diluting humid crawl space air with drier outdoor air.
Outdoor air brought in to ventilate a crawl space is often more humid than the air it’s replacing. Encapsulated crawl spaces, with sealed vents and conditioned air supply, consistently outperform vented assemblies in real-world moisture measurements.
Spray foam in a crawl space can be applied in two ways, depending on the assembly strategy:
- At the crawl space walls and sill plates. This brings the crawl space within the conditioned envelope and protects the floor framing from extreme temperature swings.
- Between the floor joists above the crawl space. Closed-cell foam is your preferred choice here since it resists moisture and remains adhered to the underside of the subfloor over time.
4. Basement Walls
Spray foam is the best choice for basements since these locations have a specific thermal situation. Interior basement wall insulation with spray foam provides several benefits. It insulates and air seals the wall. It also prevents moisture from the exterior soil from migrating through the concrete and into the interior framing system.
It’s important to note here that finished basements that have finished foundation walls can still have spray foam applications within the cavities before drywall installation. In unfinished basements, however, where foundation walls are exposed, spray foam applied directly to the concrete is the most effective approach.
5. Exterior Walls
In new construction, spray foam is applied to open wall cavities before drywall installation. Open-cell foam fills the 2×4 or 2×6 cavity completely, providing both insulation and air sealing throughout the wall assembly. Closed-cell foam is used in walls where a higher R-value per inch is needed.
An advantage of spray foam in new-construction walls is that it automatically seals around every electrical box, pipe penetration, and framing irregularity. Fiberglass batts, regardless of how carefully they’re cut and fitted, leave gaps.
In retrofit wall insulation, the approach depends on the construction type. In walls with existing exterior siding being replaced, exterior continuous rigid foam insulation is often combined with spray foam at penetrations to create a comprehensive wall assembly upgrade. For walls with finished interiors that aren’t being demolished, injection foam can be applied to existing closed cavities without full demolition.
Also Read: Spray Foam Insulation vs Fiberglass: Which Is Better for Your Home?
Is Spray Foam Insulation the Right Option?
If you’re evaluating spray foam insulation for your home, Foam Insulation Solution is who to call. We assess your building and recommend the right application for each location. From rim joists to rooflines, our team specifies and installs spray foam insulation. Schedule an assessment and find out exactly where your home is losing energy and what it takes to stop it.
