Spray Foam Insulation

What is spray foam?

What is spray foam?

Spray polyurethane foam (SPF) is a spray-applied plastic that is widely used to insulate buildings and seal cracks and gaps, making the building more energy-efficient and comfortable.

SPF insulation is known to resist heat transfer extremely well, and it offers a highly effective solution in reducing unwanted air infiltration through cracks, seams, and joints.


There are three primary types of SPF that can be used for insulation and other purposes:


Often used for interior wall cavity fill and unvented attic applications. Also known as open-cell-foam, low-density spray foam is spray applied to provide a continuous insulation and an air-sealing barrier. Low-density SPF is also called ½ pound foam, as it weighs almost 0.5 lbs. per cubic foot. The foam’s open-cell structure gives some flexibility to the hardened foam.

Low-density foam is applied as low or high-pressure, two-component polyurethane spray foam. Low-density spray foam can be applied on walls, in unvented attics, to ducts and ceilings, and in vented attics and crawl spaces. It is known as an air barrier, but permeable to vapor and moisture. It is often used to fill cavities in walls during construction.

Due to its relatively large cell structure, low-density foam stays somewhat soft and flexible after curing. Low-density spray foam provides heat insulation and seals airflow through cracks, joints and seams by filling the cavities. In addition, this foam can help absorb sound thanks to its softer texture and open-cell structure.


Often used for continuous insulation, interior wall cavity fill, and unvented attic applications.

Medium-density foam is applied as low- or high-pressure two-component spray foam. Medium-density foam offers specific benefits depending on the climate and the type of building in which it is used. Like low-density foam, medium-density SPF is often used for continuous insulation, interior wall cavity fill, and unvented attic applications. However, medium-density is a closed-cell spray foam; it is often used where there is need for the greatest R-value insulation per inch possible. Medium-density foam acts as an air, vapor, and water barrier, and can even help reduce noise.

Medium-density foam can also provide a high tensile and bond strength. It can provide low vapor permanence and is often not affected by moisture such as wind-driven rains.


Often used for exterior and roofing applications.

Services We Offer

We offer the following services for Residential, New Construction, Commercial, and Pole Barns:

  • Additions
  • Home Remodels
  • Basement Walls
  • Under Slab Insulation
  • New Construction
  • Rim Joists
Spray Foam Insulation

Spray Foam Insulation vs. Wet Blown Cellulose

As you can see, this product installation is on the messy side! That’s because about 50% of the weight of blown cellulose is water. If you’re thinking that all that moisture could potentially cause moisture issues, you would be right! This study, conducted by The Canadian Housing Information Centre on “Wet-Sprayed Cellulose Insulation in Wood-Frame Construction,” found the framing material can have the moisture content more than double and that it may take as long as five months to get the framing back to pre-installation levels.

To put this in perspective, imagine it is in the middle of a humid summer. If you spray a product that is 50% water into your new home, does this seem like a good idea? Are you willing to potentially put your project behind or on hold for several months to allow for proper drying?

You can conduct a practical test of this on your own in just a few minutes. Take some newspaper and weigh it. Then add the amount of water needed to double its weight. Once saturated, place it in your garage or basement and see just how long it takes to dry out.

Downfalls of Wet Blown Cellulose

The study also concluded wet blown cellulose is not an effective air barrier. Related to this, we have seen some cellulose contactors still using small cans of spray polyurethane insulation to air seal new homes!

With respect to wood moisture, the study reported, “Sections of the frame adjacent to the dry insulation showed normal absorption and drying rates. After the wet-sprayed cellulose was installed, the plywood’s sheathing moisture level increased to 26% after 30 days, decreased to near original levels (15%) after 160 days and dried 1% more by the end of the test (420 days).”

Moreover, it concluded the “wet-sprayed cellulose insulation nearly saturates wood framing, but within six months the framing will dry almost to the level before installation, even during winter.”

Now, keep all of this in mind, and let’s add a 3mil sheet of plastic to serve as a vapor barrier over the wet-sprayed cellulose to meet vapor barrier building code requirements. According to CertainTeed Corp., one of the largest insulation manufacturers in the country, adding vapor retarders significantly slow the drying process.


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