Why Everlast Insulation Chooses Fiberglass Products

Everlast Insulation takes our employees’ and customers’ health, comfort and safety in mind with each decision we make. That is why we install only the best fiberglass products from manufacturers like Owens Corning. To help our customers better understand why we exclusively work with fiberglass material, we’ve pulled together the following information. Specifically, we examine the pros/cons of fiberglass compared to other types of insulation, including cellulose and spray foam.


The chart below compares the qualities of blown-in fiberglass insulation versus cellulose.


Category Blown-In Fiberglass Cellulose
Gap-Free Coverage A high-pressure system means a perfect fit every time. Many cellulose contractors do not use a high-pressure system, which may lead to gaps.
Moisture Its glass make-up means zero moisture absorption. Its shredded newspaper content means the likelihood of moisture absorption. Matting, decreased performance and loss of fire protection are all concerns should the product become wet.
Chemical Content More than 99% natural ingredients Borax, boric acid, ammonium sulfate, aluminum sulfate, ammonium phosphate and zinc chloride and other chemicals are common cellulose additives.
Settling & Sagging Guaranteed not to settle in both open and closed blow applications (e.g., attics and walls) Average 20% settling rate
Combustion Naturally non-combustible material not requiring fire retardant chemical treatment Naturally combustible material requiring fire retardant chemical treatment
Weight Impact Light enough to install up to R-70 over ½” ceiling drywall with framing spaced 24” on centers without causing drywall sag Potential for ceiling drywall to sag at R-values above R-30 for regular cellulose insulation when installed over ½” ceiling drywall with framing spaced 24” on centers
Corrosion Non-corrosive with no chemicals that may corrode pipes and wires Certain chemicals (particularly sulfates) routinely applied as a fire retardant to most cellulose insulation can cause the corrosion of pipes and wires under certain conditions.
Recycled Materials Many fiberglass insulation manufacturers use up to 40% of more recycled materials in their products. The current industry average is 30% recycled content with some manufacturers using over 50% recycled content. Cellulose insulation is generally made up of about 80% recycled newspapers and 20% fire retardant chemicals. However, it takes three times more cellulose material by weight than fiberglass to insulate a typical home.
Drying Time 100% moisture free with no drying time required Wet-spray cellulose requires a minimum of 24 hours (or until maximum of 25% moisture is reached) before being covered.
Pest Infestation Fiberglass does not sustain life, so bugs, mold and mildew will not thrive. Paper, the primary ingredient in cellulose, is attractive to pests, especially termites. Although almost all present-day cellulose insulation contains an anti-termite borate treatment, we question if normal house moisture affects the borate levels enough to decrease termite control over time.
Dust Levels Fiberglass leaves very little behind in the way of dust particles. Cellulose is dusty by nature and tends to leave dust particles, especially around light and electrical fixtures.


Everlast Insulation believes fiberglass is a better cost-effective air-sealing solution, as it promotes better moisture control and thermal performance than spray foam. Additionally, the chemicals associated with spray foam give us cause for concern when it comes to its combustibility, indoor air quality and the overall safety for those who install it.

Owens Corning offers a range of educational materials discussing the differences between fiberglass and spray foam. This includes a brochure with a side-by-side comparison of fiberglass and spray foam materials. To access these materials, click here.

This video from CBC Marketplace also details the dangers of spray foam insulation when installed incorrectly.



Contact us for more information about Everlast Insulation’s products and services.

Want to learn more?