Commercial roof insulation is a layer of material in between the roof membrane and the roof deck.

The main and most important role insulation plays is creating a thermal barrier. In cooler climates insulation can help keep the cold out and in warmer climates insulation can help keep the heat out. Insulation also helps to keep hot or cold air in the building. Choosing the right insulation can save you hundreds of dollars on your energy bills every year.

Building owners should choose the insulation that’s right for them based on the climate and needs of the building as well as the budget. Listed below are three of the most common insulations used for roofing:

Polyisocyanurate (polyiso)

Polyiso is the most common insulation used. It is a closed cell foam created by heating chemicals and synthetic materials into a composite material that cools into rigid foam panels. Polyiso has an average R-Value of 5.6 and the average cost is $0.67 per square foot. This insulation offers a cost-effective option and is easy to use

Extruded Polystyrene (XPS)

XPS is one of the most expensive insulation options. This is due to the fact that it has the highest R-Value. It is a rigid foam insulation formed with polystyrene polymer using an extrusion process. It is often recognized for its distinctive color being manufactured in blue, green or pink.

Expanded Polystyrene (EPS)

While XPS has the highest R-Value, EPS has the highest R-Value per dollar. It is a closed cell rigid foam material produced from solid beads of polystyrene, often called beadboard. It does not retain water over time, which means that the R-Value of EPS is maintained longer under severe exposure. EPS is also used to insulate walls and floors as well as used for packaging and manufacturing products such as coffee cups.

Other less common insulation options are spray foam, fiberglass and mineral wool.

What is the R-Value?

The R-Value is a measurement of how well a layer of a roof system resists the flow of heat. The higher the R-Value the better. This number is calculated based on every layer in the roofing system, however, insulation has the biggest impact. The region the roof is in will also affect the R-Value as climates vary everywhere.

It’s important to remember that you should invest in the best roofing insulation for your needs. A higher R-Value may not always be the best suited for you. You should always follow the manufacturers recommendations and advice of a trusted roofing contractor. This will ensure the longest life for your roof.