Comprehensive Guide to Commercial Roof Insulation Materials

Roof insulation plays an important role in maintaining a balanced temperature inside a building. Both residential and commercial buildings need to be properly insulated. Inefficient insulation can lead to high energy bills and other issues. Commercial buildings, in particular, consume a lot of energy, so choosing the right material is essential to prevent these excessive costs.

At McClellands Contracting and Roofing, we serve property owners with top-quality roofing and remodeling services. We believe that knowing about the different insulation materials available helps you choose the right one for your building. Today, we will cover popular commercial roof insulation materials.  

What Is R-Value?

Before discussing the options available, you first need to know about R-value. R-Value determines how well a material prevents heat from passing through it. In simple terms, it tells us how good something is at keeping warmth inside a building when it's cold outside or keeping cool inside when it's hot outside.

For commercial buildings, R-value is especially important when talking about roof insulation. Commercial roof insulation with a higher R-value does a better job of keeping the temperature inside the building stable, which can save money on heating and cooling costs.

When choosing insulation for a commercial building's roof, owners and builders look at the R-value to decide which is best.

To determine the R-value of the insulation material, use a simple formula: 

→ thickness of the material / the thermal conductivity of the material

Thermal conductivity is how easily heat can flow through a material. It inversely determines the material's insulation capacity. The lower the thermal conductivity, the higher the insulation capability. 

What Are The Different Commercial Roof Insulation Materials?

Here are the different insulation materials available for commercial roofs!

#1 Polyisocyanurate

R-value: R-6.5 per inch

Cost: $0.65 to $0.85 per sq. ft.

The first option on our list is polyisocyanurate ( also known as polyiso) insulation. It is a rigid foam material used for insulation in commercial buildings. Polyiso is made from closed cells that trap air, making it great at stopping heat flow. Polyiso is very popular for commercial roofing insulation because it works well and isn’t expensive.

This insulation is good for many types of commercial roofs, including flat roofs and metal roofs. It has a high R-value, about R-6 per inch, which means it's fairly good at keeping heat in or out. This helps meet commercial roof insulation requirements and can lead to saving money on energy bills.

Polyiso has some great benefits. It's strong, resists fire, and is better for the environment than some other options. It comes in boards that are easy to install.

However, polyiso can absorb water if not properly protected, which can reduce its effectiveness. Also, its performance can slightly decrease in very cold temperatures. Overall, polyiso is a top choice for commercial building roof insulation, offering high performance and value.

#2 Polyurethane/Spray Foam Insulation

R-value: R-7 per inch

Cost: $1.25 to $3 per sq. ft.

The second insulation material on our list is polyurethane. Spray foam or polyurethane insulation is a popular commercial flat roof insulation because of its high R-value. Polyurethane is a liquid sprayed onto the roof, which expands into a solid foam. 

One big advantage of polyurethane is its great insulation capability, making it very effective for commercial flat roof insulation. It also forms a waterproof layer that stops air and water from getting in, helping to control the building's temperature and save on energy bills.

Polyurethane is a durable material that can last a long time, which is important for commercial roofs.

However, it needs a coating to protect it from sunlight and can be hard to remove if necessary.

#3 High-Density Extruded Polystyrene (XPS)

R-value: R-5 per inch

Cost: $0.60 - $1.50 per sq. ft.

High-density extruded polystyrene (XPS) is made through an extrusion process in which the polystyrene polymer is melted and mixed with additives to produce a closed-cell rigid insulation. Its high density makes it strong and durable. For commercial roofs, it's typically installed over the roof deck and directly under the roofing material rather than underneath in an attic space. 

When comparing how well it insulates to how much it costs, XPS is usually in the middle range for flat roof materials. It's not the cheapest, but it's not the most expensive either.

However, XPS has some downsides. It can be damaged by certain glues and hot tar used in roofing. Also, in some roof systems, XPS needs to be held down with heavy materials. This extra weight can be a problem for some buildings.

Overall, while XPS is useful for commercial roof insulation, it's important to consider these factors when deciding if it's the right choice for your specific building.

#4 High-Density Expanded Polystyrene (EPS)

R-value: R-4 per inch

Cost: $0.40 to $0.75 per sq. ft.

Expanded polystyrene insulation is a type of rigid foam board insulation made by blowing air into polystyrene, which inflates the material into large boards. 

They are very lightweight and provide decent insulation, which makes them a good choice for commercial roofs. 

They are also a cost-effective choice to consider. EPS boards offer great compressive power, and they are easy to install. However, it’s not as durable as some other commercial roof insulation materials like polyisocyanurate and XPS. 

#5 Perlite Board

R-value: R-3 per inch

Cost: $1 to $9 per sq. ft. 

Perlite insulation boards look like tiny, airy pebbles pressed into sheets. To make it, manufacturers heat perlite ore until it expands to about 20 times its original size. This material is then mixed with binders and formed into boards. 

Perlite board insulation is another popular commercial roof insulation choice because it has great resistance to fire and moisture, and is easy to handle and install. 

Perlite boards have a lower R-value compared to other insulation types, which means you will need to consider a thicker application to meet the commercial roof insulation requirements. It also requires proper sealing and protection from water to maintain its performance. 

How To Choose The Right Insulation Material For Your Commercial Roof

Choosing the right insulation for a commercial roof involves balancing various factors and standards. 

Key considerations include compliance with ASHRAE Standards 90.1 and 189, the International Energy Conservation Code (IECC), and local building codes, which set minimum energy efficiency requirements.

The International Building Code (IBC) and UL or FM standards ensure safety and fire resistance. For those aiming for a green certification, the International Green Construction Code (IgCC) and LEED Rating System provide additional guidelines. 

When selecting insulation for your commercial roof, consider your climate. Colder regions require higher R-values. 

Another important thing to consider is your budget. Options like spray foam are more expensive upfront but provide a higher R-value, potentially leading to more energy savings. Ultimately, consulting with a roofing professional can help you find the best insulation material for your specific commercial building needs.

Call McClellands Contracting and Roofing For Your Roof Installation In Pittsburgh, PA

If you are looking for a commercial roof installation in Pittsburgh or the surrounding areas of Pennsylvania, we are here to assist you. At McClellands Contracting and Roofing, we aim to provide top-quality roofing services including roof repair and replacement services. 

Our commitment to quality workmanship makes us one of the best-rated roofing contractors in Pennsylvania. Trust us as your reliable roofing contractor and for the best results. To learn more about our services, feel free to call us at (412) 353-5660.