SPF Roofing vs Metal Roofing: Which is Best for Commercial Buildings?
When we meet with future clients, they are usually comparing several types of roofing systems. We are always asked: Which is better? Which is more affordable? Which is best for long lasting protection?
At West Roofing Systems, we want to make sure that our future clients have the best information available. For this reason, we created an article that explores the differences between metal and SPF roofing systems to give you all the information you need in choosing which roof for your facility.
Metal Roofing is one of the oldest commercial roofing systems on the market.
Most metal roofing systems use corrugated galvanized steel, although other materials such as aluminum or tin can also be used. After a metal roofing system is installed, a coating can be added for waterproofing, rust protection, and UV protection.
Spray Polyurethane Foam (SPF) Roofing
Spray Polyurethane Foam, more commonly referred to as SPF, is a material that is sprayed and expands into a foam, creating a solid layer across an existing roof.
While SPF roofing is not the most known type of roofing material, the technology has been around since the early 1960s for industrial, commercial, and residential facilities.
For an average commercial roof, it will usually cost between $5.00 and $10.00 per square foot in materials and labor to install a typical metal roofing system. This price range can change depending on the type and style of the metal panels you choose.
For an average 20,000 sq. foot commercial roof, it will usually cost between $4.00 and $7.00 per square foot in materials and labor to install a typical SPF roofing system. This price range is for an SPF roof of average thickness and building structure.
Since metal roofing material is rather light in weight, it can be installed right on top of the existing roof. A contractor will install a frame, or substrate, with trusses and purlins for the metal roof to be fastened to.
After the existing roof is prepared, your contractor will install a layer of insulation. There are a few types of insulation options available:
- Roofing Felt
- Rigid Board
- Bubble Insulation
- Spray Foam
After the insulation is installed, metal panels are cut and attached to the frame with screws. These panels are installed with overlapping edges to cover all the exposed insulation underneath. Flashings are mounted on the joints of the roof.
Before the installation can start, the existing roof needs to be prepared. Rather than stripping the existing roof, the contractor will most likely prepare the substrate by getting rid of all dirt, dust, and contaminants.
The first layer put down by the contractor is the polyurethane foam. This foam is created by combining two liquids as it’s sprayed onto the existing roof substrate. As the liquid is sprayed onto the existing roof, it expands to form a solid foam surface.
When the SPF layer has been completed, it is then coated with a layer(s) of elastomeric silicone or acrylic coating with embedded granules.
If properly installed and maintained, a commercial metal roof can last 40 years. There are quite a few other benefits of metal roofing systems:
Design – Variety of material and color choices.
Stability – Ability to hold up to high winds and snow.
Energy Efficient – Sheet metal can be made from recycled steel.
Fire Resistance – The metal panels will not burn in the event of a fire.
If properly installed and maintained, a commercial SPF roof can last 50 years. There are quite a few other benefits of SPF roofing systems:
Energy Efficient – SPF delivers thermal, air, and moisture barriers to provide the highest R-value per inch.
Durable – The foam material can expand and contract with the building, decreasing the likelihood of cracks and splitting.
Seamless and Waterproof – The continuous solid surface does not require joints or seams, removing the most vulnerable area for leaking.
Environmentally Friendly – In most cases, there is minimal stripping of the original roof – eliminating the need for costly roof tear-offs and waste.
While metal roofing systems can have a long lifespan, this can only be obtained if the roof is maintained properly over the years. This includes a coating to avoid rust, replacing and re-fastening damaged panels. Here are other disadvantages of metal roofing systems:
Water Damage – If water ponds on the roof it can cause severe damage, such as rust.
Full Replacement – The substrate, or frame, is often cumbersome and difficult to work with. They require a complete tear off in almost every replacement instance.
Seams – The metal panels create seams that are prone to water leaks.
Durability – Since the metal panels are attached to the substrate, if they are not installed correctly they can become loose when they expand and contract.
Noise – Weather such as rain, hail or wind can create a lot of noise against the metal material.
While the advantages of an SPF roofing system outweigh the disadvantages, there are a few things you should keep in mind. Here are disadvantages of SPF roofing systems:
Hire the Right Professional – The contractor needs to be precise with the application and have a solid understanding of the chemicals they are using.
Limited Installation Window – Installation of an SPF roofing system cannot be performed during cold, windy, or rainy weather.
Overspray Potential – Since the SPF is installed by a spray application, there is a risk of the wind carrying overspray onto surrounding cars and other surfaces.
Limited Colors – The silicone coating that is applied to the foam comes in two colors: white and gray.
Maintenance – SPF roofing systems need to be inspected twice a year at least.
As you can see, both SPF and Metal Roofing Systems have their benefits and drawbacks. Choosing which one is best comes down to a customer-by-customer basis.
West Roofing Systems, Inc. installs sustainable and efficient roofing systems for commercial, industrial, manufacturing and municipal buildings. In over 37 years, we have installed over 56,000,000 square feet of commercial Spray polyurethane foam (SPF), single ply membrane and other popular roofing systems.
If you are looking for maintenance, repair or replacement for your facilities roof, fill out our quote form for your free no-obligation commercial roof quote from our team of experts.
Author: Aubrey Barto
Aubrey Barto is the Marketing Manager of West Roofing Systems, Inc. She has two BAs in News and Media Production with Certifications from Hubspot, HootSuite, University of San Francisco and Wharton School of Business. Aubrey works closely with West Roofing’s sales and service teams, she is up on our roofs taking photos and videos for our website regularly.