Building a new home? There are so many areas to insulate now to lower your energy bills for as long as you live there. Learn all the important terminology for new construction insulation.
Check out the 25 most important terms related to insulation in a new build home.
Air-Sealing
Air-sealing describes sealing up gaps, cracks, and crevices in a build. Traditionally, homes are built to "breathe" and have many places where air leaks. As construction science advanced, having an airtight home became more important. Air-sealed homes are more efficient and affordable for heating and cooling.
Air Barrier
Air barrier is a term used interchangeably with air-sealing. When a product offers an air barrier, it can create an air-seal. Some examples include caulking, can foam, house wrap, and spray foam insulation.
Vapor Barrier
Similar to an air barrier, a vapor barrier stops vapor transfer. Vapor barriers are vapor impermeable. The barrier can also prevent vapor content from condensing by preventing it from traveling.
Warm air holds more vapor than cold air. In some areas of construction, like underground places, the exchange of warm and cool air can end with condensation.
Vapor barriers are complex, and best explained and handled by an insulation professional. Your climate zone will determine how vapor barriers should be installed in your home.
Blower Door Test
A blower door test measures the air leakage in a home. According to new building codes, newly built homes must pass a blower door test to pass inspection. It's easiest to pass a blower door test by air-sealing during construction. If air-sealing methods have been implemented, air leakage will have been reduced, and the house will pass the test.
Blown-In
Blown-in is a type of insulation often used in new construction. Blown-in can come in fiberglass or cellulose. Our team prefers cellulose because it is safer to touch or disturb than fiberglass.
Blown-in is meant for attic applications. A thick layer of insulation is installed on the attic floor, creating a thermal barrier between the living space and the attic. We recommend pairing blown-in insulation with an airtight seal to maximize the performance of the insulation. Blown-in with an air-seal prevents heat transfer in all three forms.
Open Cell Spray Foam
Open cell spray foam is one of two types of spray foam insulation. Open cell is a less dense foam that expands and fills cavities more rapidly than closed cell. In our climate zone, open cell is used for exterior walls, in-between floors, and in attics.
Open cell spray foam offers an air-seal. Spray-applied, it seamlessly insulates and air-seals wherever it is installed. While this insulation is pricier than blown-in, it offers more performance and longevity.
Closed Cell Spray Foam
Closed cell spray foam is the other of two types of spray foam insulation. Closed cell is a more dense foam. It doesn't expand as much as open cell, but this tight cellular structure allows it to offer a vapor barrier in addition to an air barrier.
Since closed cell can create a vapor barrier, it is much more versatile than open cell. Closed cell can be installed in attics, basements, crawl spaces, and exterior walls. As a type of spray foam, closed cell is spray-applied and offers seamless, long-lasting performance. However, closed cell is also one of the more expensive insulations available.
Fiberglass Batt
Fiberglass batt insulation is the most common insulation for new construction. Batt insulation has been around for decades and is among the most affordable insulations. Batt insulation is installed all throughout a home, but it doesn't perform well in all areas.
Fiberglass insulation cannot offer an air or vapor barrier, so it isn't ideal for basements or crawl spaces with moisture concerns. Fiberglass can be used alongside closed cell spray foam in a hybrid system. Hybrid systems provide the vapor barrier of closed cell with the affordability of batt.
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While fiberglass may be quite affordable up front, its performance leaves much to be desired. A home insulated with fiberglass batt will have higher energy costs over its lifespan. One of the best applications for fiberglass is interior walls. However, attics and exterior walls have better insulation options.
Dense Pack
Dense pack cellulose is an insulation option for exterior walls and cathedral ceilings. Both blown-in cellulose and dense pack cellulose start from the same material. The dense pack installation method is quite different. Installed correctly, dense pack can offer vapor and air barriers.
Dense pack cellulose is installed directly into wall cavities covered with netting to hold the insulation inside.
Cellulose Wall Spray
Cellulose wall spray is sometimes confused with dense pack. While both methods involve loose-fill cellulose and wall insulation, cellulose wall spray is a different method. With cellulose wall spray, some water or adhesive are added to help the particles adhere in place.
Wall spray is the same for interior and exterior walls. This insulation type needs only a suitable surface to spray to and studs to spray between.
R-Value
R-value, or resistance value, measures how well a material resists conductive heat transfer. All insulation materials have a good R-value. Insulation must also meet certain R-values in construction to be up-to-code.
R-value is a crucial insulation metric but not the only metric to remember. Air-sealing and vapor barriers are also vital for certain applications.
Draftstopping
Draftstopping is an important method in construction for fire prevention. Every assembly, from the walls to the ceiling, is designed to prevent fire from spreading. Draftstopping methods are laid out in building codes and vary based on home design and square footage.
Vaulted Ceiling
Many ceilings are flat, but a vaulted ceiling is not. Vaulted ceilings open up a space. These ceilings can mimic the slope of the roof or can have trusses to create unique slopes or shapes. When a ceiling is vaulted, the space around it still needs to be insulated.
Cathedral Ceiling
A cathedral ceiling is a type of vaulted ceiling. Cathedral ceilings follow the slope of the roof, coming to a point where the two slopes meet.
Kneewall
If you plan to use your attic as conditioned space, your attic will have kneewalls. Kneewalls are small walls on the edge of an attic floor. If you picture a leg kneeling on the ground, the kneewall makes up the thigh of the leg, while the attic floor is the calf. Below the attic floor, the space is conditioned. Within the attic, the air is conditioned. However, the triangle formed by the roof, attic floor, and kneewall is not conditioned.
It is important to insulate properly against these kneewalls to prevent any air leakage from the unconditioned space.
Headers
A header is an additional framing element in above doors, windows, and other sizeable openings in a wall. Headers create an opportunity for air leakage unless the cracks and crevices are sealed.
Slab-on-Grade
Slab on grade is a type of home foundation. If you plan to build on a slab, you may opt for a slab-on-grade foundation. This style of foundation has a vapor barrier installed beneath the concrete.
Crawl Space
Not every home has a crawl space. Other houses have slab foundations or basements. The crawl space is often home to plumbing or HVAC equipment. Crawl spaces need proper insulation to avoid the moisture concerns that accompany being underground.
Our team recommends a method called encapsulation to insulate a crawl space properly. Encapsulation uses insulation, air barriers, and vapor barriers to keep the area clean, dry, and accessible.
Basement
If your home doesn't have a slab or crawl space foundation, it likely has a basement. New homes have block or concrete foundation walls. Being underground, these masonry walls risk moisture transfer.
Whether or not you finish your basement, you will benefit from a vapor barrier downstairs.
Band Board
The band boards are the parameter framing where the floor system sits in the foundation wall. This piece of lumber is where the floor joists terminate into on the exterior of the home.
Band boards are an area where air can easily leak. Your band boards should be air-sealed appropriately to avoid this air leakage.
Rim Joist
Rim joist is another term that describes band boards. These terms are often used interchangeably, including in our resources at South Central Services.
Single-Story
Single-story homes have only one floor and are more straightforward to insulate. If there is a basement, it can be included in or removed from the conditioned space. Likewise, the attic can be included in the conditioned space or cut off from the HVAC system.
No matter where the thermal envelope stops in a single-story home, the envelope needs an airtight seal.
Two-Story
When insulated poorly, two-story homes risk different temperatures on every floor. The upstairs level can be significantly warmer than the downstairs in the summer. In winter, the phenomenon reverses.
Two-story homes need a defined thermal envelope with an airtight seal. With less air infiltration, the HVAC system can more efficiently distribute heating and cooling.
One-and-a-Half-Story
One-and-a-half-story homes present some interesting challenges when insulating. A Cape Cod home is the most common example of a one-and-a-half story. Insulation is meant to support the efforts of the HVAC system to condition the home. Without insulation clearly defining the thermal envelope, certain sections of the home can be less comfortable.
Performance
The performance of insulation is not always discussed. Every insulation offers a different degree of performance. Even if two insulation products have the same R-value, they can still deliver different performance.
The point of insulating a home is to achieve efficient performance. Insulation shouldn't be put into the walls just to meet building codes. Insulation is one of the most difficult elements of a home to renovate or replace. Often, we retrofit in accessible areas like the attic, basement, and crawl space. Wall insulation isn't reasonable to replace unless major renovations are taking place.
Since insulation can be difficult to upgrade in the future, it makes sense to get the best performance you can afford for your new home.
Ready To Insulate Your New Home?
Now you know all the important terms to understand when considering insulation for new construction. Many home areas need proper insulation, air-sealing, and vapor barriers.
If you're ready to talk about insulation for your new home, reach out to our team for a free quote. Or, learn more about new build insulation on our website, starting with these resources:
- Decide if investing in pricier insulation is worth it for your new home
- Discover the best way to insulate your new house
- Weigh the pros and cons of building new
Disclaimer: While we strive to publish information accurate to building science, local building codes and standards supersede our recommendations.
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