Commercial Roof Insulation: The Good, the Bad and the (Mildly) Ugly

The type of insulation a commercial roof system contains is an essential part of the system’s performance. Because roof coverings can become quite hot in summer and cold in winter, insulation is needed to help a building’s climate control system operate efficiently and prevent structural components beneath the roof surface from experiencing premature wear due to temperature fluctuation.

Several types of commercial roof insulation can be used to accomplish these goals, with each possessing benefits and drawbacks, depending on building construction and the wants and needs of the building owner. With this in mind, we take a look at the good, the bad, and the ugly of five commonly used types of commercial roofing insulation to provide information to help you determine which type of insulation to use.

1. Fiberglass

Fiberglass is a long-lasting material that is used for roof insulation in three primary forms:

• Ridged boards for flat commercial roofs
• Fiberglass batts and rolls that are manually installed
• Blow-in loose fiberglass for under the roof deck installation

Because batts and rolls are perfect for filling large cavities but not for sealing small gaps, and because blow-in fiberglass is great for sealing small gaps but isn’t so efficient for filling large cavities, both types of insulation may be used simultaneously.

On the downside, care must be taken during installation and afterward to prevent building occupants from inhaling fiberglass particulate that is released when strips of insulation are cut or when loose fiberglass is blown into the insulation space using a special machine.

2. Spray Foam

Some providers of commercial roofing services view spray foam insulation as a good alternative to fiberglass insulation. There are a few reasons why. First, the foam has been shown to reduce energy operating costs by up to 50%. Second, because the foam is formulated to expand and fill insulation cavities, it can be applied with the assurance that small gaps are filled. Third, the insulation can be applied under the roof or on top of it as a protective sheath.

Depending on your wants and needs, spray foam commercial roofing insulation can also have some downsides, particularly the fact that it often costs more than conventional insulation materials (e.g., fiberglass and cellulose) and involves a messier installation process, which can extend project completion time by way of extending cleanup time.

3. Foam Board

Foam board insulation is commonly applied in four major types: expanded polystyrene beadboard, extruded polystyrene, poly isocyanurate, and composite foam. All four types excel at thwarting thermal conductivity from the roof surface, can feature rigid durability, and are available in large panels (e.g., 4 x 8 feet) that help decrease turnaround time for insulating large roofs.

Foam board insulation can have some disadvantages, too. Unless sections of the board are perfectly cut to fill insulation cavities and seams between board sections are sealed with special tape, the insulation can allow air that’s above it to infiltrate building areas below.

4. Mineral Wool

Mineral wool insulation has several excellent qualities: It is highly sound resistant (sometimes, it is used for sound dampening alone), exceptionally fire resistant, and provides an insulation barrier that’s quite effective for supporting climate control in a building’s occupied areas.

When building owners decide not to use mineral wool for commercial roofing insulation, it’s often because the material produces slivers that are easy to inhale and cause respiratory distress, and is reputed to cause cancer via DNA slicing and cell mutation. However, these threats can generally be overcome through proper installation and sealing procedures.

5. Cellulose

Cellulose commercial roofing insulation is made from various types of paper. Some of its primary advantages are affordability (up to 25% more affordable than fiberglass insulation), few health risks compared to other types of insulation, and excellent mold deterrence, fire resistance, and insect deterrence when it is pretreated with boric acid.

Some major disadvantages of cellulose installation are that it often requires a vapor barrier to be installed, creates a large amount of dust during the installation process, and can require a higher installation cost than fiberglass insulation, thus partially negating its benefit of being more affordable to purchase than fiberglass insulators.

Recycle What You Remove

Depending on the size of a commercial roof, re-insulating it can produce lots of spent insulation that has one of two destinations: a landfill or an insulation recycler. Recycling is the better choice by far:

• Fiber glass can be recycled into new fiberglass products
• Foam can be recycled into packing and cushioning
• Mineral wool can be recycled into filler for plastic and wood composite products
• Cellulose can be recycled to create thousands of products that feature full or partial paper composition

The easiest way to recycle commercial roofing insulation is to work with a roofing contractor that understands recycling and sustainable roofing system design, and will forward used materials to the proper recyclers. In addition to helping the environment by keeping waste out of landfills, recycling your roofing insulation will reduce your waste disposal costs.
Sentry Roof uses all types of commercial roofing insulation. If you have any questions about the insulation used in your current roofing system or which one might be best for your next roofing system, feel free to give us a call.