Spray foam (SPF) roofing is closed-cell polyurethane foam sprayed over an existing roof and sealed with an elastomeric topcoat. It suits low-slope commercial and industrial roofs that need more insulation, better drainage or a seamless surface over complex details. The roof underneath has to be dry enough to stay in place, and a badly saturated roof usually needs a tear-off first.
Spray polyurethane foam (SPF) is sprayed directly onto the existing roof deck, expanding into a seamless, fully-adhered membrane that insulates and waterproofs in one step. Because it’s seamless, there are no laps or seams for water to find.
Strong Contractors is an SPFA-accredited installer, applying SPF systems finished with a protective siliconee or acrylic coating to guard against UV degradation and foot traffic.
SPF is unforgiving of bad technique — inconsistent spray thickness or the wrong weather window can compromise the whole system. Our crews monitor deck temperature, humidity, and wind before every application, and we verify foam thickness with core samples across the roof.
That process is what makes SPF systems some of the longest-lasting, best-insulating roofs we install.
With both certifications, Strong can check the roof for asbestos and handle the encapsulation itself.
Unlike a factory-made sheet, spray foam is made on the roof as it goes down. A typical project follows these seven steps, from survey to recoat plan.
The Spray Polyurethane Foam Alliance is the trade association that accredits SPF roofing contractors, Strong among them. We share its roofing video so you can hear about spray foam straight from the industry body.
Video courtesy of the Spray Polyurethane Foam Alliance (SPFA)
| Spec | Typical Value |
|---|---|
| Foam type | Closed-cell spray polyurethane foam |
| Minimum foam thickness | Typical: 1 in.; thicker for insulation or slope |
| Insulation example | 3.5 in. of foam to meet R-21 (Centennial Water tank lids) |
| Topcoat | Elastomeric silicone, urethane or acrylic in multiple passes |
| Surface option | Broadcast roofing granules |
| Compatible substrates | BUR, modified bitumen, metal, concrete; EPDM, PVC, TPO with cover board |
| Recoat interval | Typical: every 10 to 15 years |
| Warranty | No Dollar Limit (NDL) manufacturer warranties, typically 10 to 20 years depending on the system |
Spray foam is priced on the roof in front of us, not from a per-square-foot list. These are the factors that move an SPF bid the most.
The infrared survey decides how much wet insulation and failed material must be removed and replaced before spraying. A dry roof keeps that line small.
Every added inch of foam adds material and spray time. A roof that must reach a set R-value needs that thickness across the whole area, plus extra where slope is built in.
Coating chemistry, the number of passes and granules all change material cost and the warranty options.
Penetrations, curbs, parapets and rooftop units need hand detailing, which adds labor beyond the open field.
Secure sites, occupied buildings, overspray control near vehicles and neighbors, and winter work that needs a heated enclosure all add planning and labor.
| Spray Foam (SPF) Roofing | Silicone Roof Coatings | TPO Roofing Systems | ||
|---|---|---|---|---|
| Existing roof | Usually stays in place if dry | Stays in place if sound | Torn off, or recovered where eligible | |
| Adds insulation | Yes, set by foam thickness | No | Yes, with new insulation boards | |
| Seams | None | None | Heat-welded seams | |
| Ponding water | Foam can be sloped to drain | Tolerates ponding; adds no slope | Tapered insulation can add slope | |
| Long-term upkeep | Recoat every 10 to 15 years | Inspect and recoat with silicone | Seam and flashing repairs | |
| Strongest fit | Needs insulation or has complex geometry | Weathered but dry membrane | Wet or failed roof assembly | |
Here are the accreditations, licenses and certifications Strong holds, plus the awards and rankings it has earned.
Strong is the only SPFA Accredited Roofing Contractor in Colorado and one of only 15 in the country.
2025
Strong's spray foam roof at South Park Elementary School in Pueblo earned a category win and a runner-up finish.
Strong is licensed to apply Gaco roofing systems.
2023, 2024
Gaco named Strong a Top Contractor two years in a row.
2024
Strong ranked No. 2,769 on the Inc. 5000, No. 165 in Construction, No. 74 in Colorado and No. 60 in the Denver metro.
Strong is certified to inspect buildings for asbestos-containing materials.
Strong is certified to carry out and supervise asbestos work.
Strong Contractors takes on spray foam, coating, and ballast removal projects outside Colorado, bringing our own crews, equipment, and project management to the job. Before we bid an out-of-state project, we confirm that state’s licensing, registration, and permit requirements so the work moves forward cleanly.
A spray foam roof can stay in service for decades when it is recoated about every 10 to 15 years. The topcoat takes the UV and weather. When it wears, the roof is cleaned, repaired and recoated with the same coating type instead of torn off. Recoat warranties are available after an inspection that includes an infrared assessment of the existing foam.
Usually, yes. SPF can go over built-up roofing, modified bitumen, metal and concrete. EPDM, PVC and TPO roofs need a cover board first. Condition matters more than type, so an infrared survey comes first. On a Florida tar-and-gravel roof at Eglin Air Force Base, crews cleared the loose gravel, then applied foam and a urethane coating with granules.
It means the Spray Polyurethane Foam Alliance has tested the contractor’s knowledge, field work and safety program. Accreditation requires 8 hours of closed-book professional exams, 4 hours of field exams, more than 500,000 square feet of proven SPF roofing experience and safety training for the entire crew. Strong holds SPFA Accredited Contractor status and has installed 1,000,000 square feet of spray foam.
Small punctures and gaps are sealed with a mastic or sealant matched to the topcoat, so a silicone-coated roof gets a silicone-based product. Larger areas damaged by UV or moisture are ground down to sound foam, primed, re-foamed at least 1 inch thick and finished with new coating and granules.
Often, yes. If an asbestos-containing roof is in good condition, spray foam and a coating can encapsulate it in place, sealing the fibers instead of disturbing them in a tear-off. Whether it is allowed depends on the roof’s condition and the regulations that apply to your building.
Strong completed five roofing projects for Pueblo School District 60 with spray foam and silicone in under four months in 2024. One of them, South Park Elementary, won the Small Business award and was runner-up for SPF Roof Over 40,000 Square Feet at the SPFA Industry Excellence Awards. Strong is also a Gaco Licensed Applicator, named a Gaco Top Contractor for 2023 and 2024.
