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Commercial Roof Insulation: What You Need to Know


Posted by Emmit | October 18, 2022 | Reading Time:

The roof and roof membrane of any commercial building are integral parts of protecting the structure and the people inside it. But commercial roof insulation is another aspect of the roofing system that plays a major role in how a building withstands regional climates.

Roof insulation helps regulate internal building temperatures and can significantly impact heating and cooling costs. Let’s discuss what types of commercial roofing insulation are widely available and what factors should be considered when installing or replacing insulation on a flat roof.

We’ll also discuss what happens when roof insulation is past its prime and why your roofing contractor may recommend replacing older insulation materials.

Why Roofing Insulation Is Important

Commercial roof insulation is typically installed underneath the protective membrane on a flat-roofed building. Insulation has several vital roles in maintaining the safety and comfort of your commercial space.

Providing Thermal Resistance

Perhaps the most apparent benefit of roof insulation is that it can save you money on your energy bills. In the winter, roofing insulation keeps the heat inside your building; in the summer, it keeps hot air outside.

Regions that experience very hot and cold temperatures (see: Virginia) especially benefit from roof insulation with a high R-value. R-value is a measure of how well a given insulation material works. The higher the R-value, the better the insulation is at resisting heat flow.

Each insulation material has a specific R-value and performs differently in regulating heat flow in and out of your commercial building.

Soundproofing & Acoustics

Another benefit of roofing insulation for commercial structures is that it can help improve the acoustics inside your building. Roofing insulation can reduce noise from outside sources, such as traffic, construction noise, and inclement weather.

This can be a great way to improve the working environment for your employees, making it easier to concentrate and collaborate. Sound ambience may be an important part of your atmosphere if your commercial space welcomes customers or visitors.

Additional Impact Resistance

Many exterior building materials can help defend your structure against harsh weather, and roofing insulation is no exception. Your commercial roof membrane or coating acts as the waterproof layer against rain and snow. But some types of roofing insulation can improve impact resistance to hail and other debris falling on your commercial roof.

Fire Mitigation

Fires can spread quickly in commercial buildings that contain flammable materials. Fire-resistant roofing insulation can slow the spread of fire from one building area to another.

If you require fire-resistant roofing, look for UL Class A rating or FM Class 1 rating materials. A Tidewater Roofing specialist can help you select materials that qualify for commercial fire-resistant roofing.

Types of Commercial Roof Insulation

There are many roof insulation options available for commercial application. Choosing the best insulation material for your commercial building is always made easier with the help of a roofing professional.

But here are some of the more common types of commercial roof insulation and what to expect from their performance.

Polyisocyanurate (Polyiso or ISO)

Polyiso is a type of roofing insulation that is made from polyurethane foam. It’s a popular type of insulation for commercial buildings because it has a high R-value, which means it is very effective at keeping heat inside the building.

Polyiso is also very fire resistant and does not emit any toxic fumes when burning. The manufacturing process for ISO implements eco-friendly practices to produce insulation boards.

High-Density Extruded Polystyrene (XPS)

Extruded polystyrene (XPS) is another type of roofing insulation made from polystyrene foam. It has a slightly lower R-value than polyiso but is still an effective roofing insulation for commercial buildings. XPS is also very fire resistant and considered a middle-of-the-road option for cost vs. R-value benefit.

Expanded Polystyrene (EPS)

EPS also uses polystyrene foam in manufacturing but has a lower R-value compared to Polyiso and XPS.

This roof insulation is more affordable to purchase and install but lacks the same fire resistance as other commercial insulation. EPS can shrink and warp under high temperatures and is not as durable as other polystyrene (a type of plastic) insulation products.

Mineral Wool

Mineral wool is a type of roofing insulation made from natural minerals such as glass and ceramic spun into sheets or rolls. It’s a popular type of roofing insulation for commercial buildings because of its high R-value, good fire resistance, installation flexibility, and resistance to mold.

This insulation is also referred to as mineral or glass fiber batts.

Spray Polyurethane Foam (SPF)

Polyurethane sprayed-on foam insulation, or simply “spray foam,” is high R-value insulation applied to commercial roofs and buildings. It is applied directly to roofing substrates with a spray gun and conforms to the shapes and surfaces of the roofing materials.

After curing, this insulation has superior performance and moisture resistance. Because of this, spray foam is often used in commercial buildings with freezers and coolers. 

Spray foam does require certain application conditions (temperature and humidity) but has high fire resistance and long-term stability as an insulation material.

Perlite Board

Perlite board combines recycled paper products and other substances in the manufacturing process to produce an economical and eco-friendly roofing insulation material. This product is considered a low thermal insulator and is more moisture sensitive than other insulation types.

Due to its maintenance requirements and low R-value, perlite board is not considered an ideal roof insulator for most commercial buildings.

Why Commercial Insulation Needs to Be Replaced

In a perfect world, your commercial roof insulation should last as long as your other roofing materials. But structural damage, water leaks, and age can cause insulation to perform poorly or need replacement. 

Water Damage

Commercial roof insulation is not designed to hold water or stay wet for an extended period. If the watertight membrane on your commercial roof fails, it’s very possible your roof insulation will be exposed to moisture.

Moist commercial roof insulation is bad for 2 reasons:

  • Insulation does not perform well when wet, lowering thermal efficiency and increasing energy costs.
  • Damp insulation is likely to develop mold and mildew, which can easily spread to other parts of your building.

If your roof membrane has been punctured or damaged, or you suspect water has entered your roofing structure, you should contact a commercial roofing contractor for an inspection.

Insulation Aging

Studies have shown that some insulation experiences aging, which lowers its effective R-value. Some foam roof insulations use gases during the manufacturing process. These gases dissipate over time and reduce the insulation’s performance.

Cracks and gaps that form between the insulation and other roofing materials can result after years of natural temperature changes. These gaps and spaces contribute to older roof insulation suffering increased heat loss.

Unexpected rising utility bills are a possible sign that roof insulation in your commercial space is aging and losing efficiency. Some roof insulation materials can last for several decades. But it’s a good idea to have a roofing professional inspect your insulation when repairs or maintenance are completed.

Insurance Purposes

Depending on the type of business or industry operating in a commercial building, insurance coverage may require that roofing materials are replaced or inspected periodically. Some companies may require a specific fire rating for their roof insulation.

Understanding the exact age of existing roof insulation can be tricky. Insulation materials are not always installed at the same time as the roofing exterior. An unexpected jump in heating or cooling bills could indicate that your roof insulation needs an update.

Insulate Your Business Risk

Roof insulation is essential to your commercial space and contributes to your building’s safety, comfort, and efficiency. Regular commercial roof maintenance can help identify when commercial insulation should be replaced or repaired.

There are many options when it comes to selecting a commercial roofing material, and it’s important to consider R-value (thermal resistance), fire resistance, and budget. But make sure you’re protecting your business and the people inside with insulation suitable for your climate and industry.

Tidewater Roofing specializes in commercial roof repairs and replacements. Our team is always available to provide expert recommendations on roof insulation when you’re ready to improve your commercial infrastructure.