IFRM Coatings
Intumescent Fireproofing in Denver, Colorado
When your design calls for exposed structural steel, intumescent coatings deliver code-required fire protection without hiding the steel. Thin-film coatings that look like high-end paint until heat activates their protective char layer. Andrex has been applying intumescent systems across the Front Range for decades.
What Is Intumescent Fireproofing?
Intumescent fireproofing is a specialized passive fire protection system that uses thin-film coatings to shield structural steel from fire damage. Unlike traditional spray-applied fireproofing (SFRM) that encases steel in a thick cementitious material, intumescent coatings are applied in thin layers that look and feel like high-quality paint under normal conditions. The result is a clean, smooth finish that preserves the architectural lines of exposed steel members.
The science behind intumescent coatings is what makes them remarkable. At ambient temperatures, the coating sits dormant as a thin film. But when exposed to extreme heat, typically 400 degrees Fahrenheit or higher, a chemical reaction is triggered. The coating begins to swell and expand, growing to 20 to 50 times its original thickness. This expansion creates a thick, meringue-like insulating char layer that dramatically slows heat transfer to the underlying steel.
This char layer is the key to intumescent performance. By insulating the steel from the fire, the coating helps the structural member maintain its load-bearing capacity for the duration specified by the fire rating, typically 1 to 2 hours for most commercial applications. The steel stays below the critical temperature where it begins to lose strength, buying occupants evacuation time and firefighters the window they need.
Intumescent coatings are also known as IFRM (Intumescent Fire-Resistive Material) in industry specifications. They are available in two primary formulations: water-based and solvent-based. Water-based products like SprayFilm WB3 are the most commonly specified for interior applications due to lower VOC emissions and easier cleanup. Solvent-based products are sometimes preferred for exterior applications or environments where moisture resistance during curing is a concern.
Intumescent coatings are the go-to solution whenever structural steel is exposed as an architectural feature. Think of the dramatic exposed steel columns in a hotel lobby, the soaring beams in a modern office atrium, or the industrial-chic aesthetic in a restaurant or brewery. In every case, the architect has intentionally designed the steel to be visible, and intumescent coatings let that design intent come through while still meeting building code fire protection requirements.
SFRM vs. Intumescent: When to Choose Which
Both SFRM and intumescent coatings protect structural steel from fire. Both meet International Building Code (IBC) requirements. The decision between them comes down to visibility, budget, and fire rating requirements. Here is how they compare:
Spray-Applied Fireproofing (SFRM)
- Best when steel is concealed behind walls, ceilings, or soffits
- Lower cost per square foot
- Achieves higher fire ratings (up to 4 hours)
- Thicker application (3/8 inch to 1+ inches)
- Rough, cementitious texture
- Faster application for large areas
- Industry standard for most commercial construction
Intumescent Coatings (IFRM)
- Ideal when steel is visible and aesthetics matter
- Smooth, paint-like finish
- Ratings from 1 to 4 hours depending on product and steel section
- Thin-film application (varies by rating and section)
- Can be top-coated in any color
- Preserves architectural steel profiles
- Required for lobbies, atriums, and exposed designs
Cost Considerations
Intumescent coatings typically cost 3 to 5 times more per square foot than SFRM. This premium is driven by the cost of the coatings themselves, the more precise application process, surface preparation requirements, and the multi-coat application system. However, this cost is often justified because the alternative, concealing the steel with drywall or a soffit system, can cost even more and defeats the architectural intent. On many projects, we apply SFRM to concealed steel and intumescent coatings only to the exposed members, optimizing the fire protection budget.
Products We Apply
As an authorized Cafco applicator, Andrex has access to the full range of intumescent fire protection products. We apply the products specified by the project engineer, and we can also advise architects and GCs on product selection when the specification is performance-based. The products we most commonly apply include:
SprayFilm WB3
Water-based intumescent coating for interior structural steel. Low VOC, UL-listed for up to 4-hour fire ratings. The most commonly specified intumescent product on Colorado commercial projects.
Cafco SprayFilm
Full line of Cafco intumescent products for various steel configurations and fire rating requirements. We are factory-trained on proper application techniques and DFT measurement.
Solvent-Based Systems
For exterior applications or environments where fast cure times and moisture resistance during application are critical. Applied per manufacturer specifications.
Compatible Top Coats
Manufacturer-approved top coat systems that protect the intumescent base coat and provide the finished color specified by the architect. Available in any standard paint color.
Where Intumescent Coatings Are Used
Intumescent fireproofing is specified on projects where the structural steel is part of the architectural vision. Any time steel will be visible in the finished space, intumescent coatings are typically the required fire protection method. Common applications in our Denver-area project portfolio include:
Lobbies and Atriums
Hotels, corporate headquarters, and public buildings with soaring steel-framed entrance spaces.
Restaurants and Retail
Industrial-chic restaurant designs, breweries, and retail spaces featuring exposed steel as a design element.
Modern Office Spaces
Open-ceiling office designs with exposed beams, columns, and steel deck where the raw structure is the aesthetic.
Renovation Projects
Existing buildings where concealed SFRM is being removed and replaced with intumescent coatings during a design upgrade.
LEED and Green Buildings
Sustainable building projects where low-VOC water-based intumescent products contribute to indoor air quality credits.
Cultural and Public Venues
Museums, performance halls, convention centers, and transit stations with architecturally significant exposed steel structures.
Our Intumescent Application Process
Intumescent fireproofing demands a higher level of precision and quality control than standard SFRM. Each step in our process is designed to ensure the coating performs as rated and delivers the architectural finish quality your project requires.
Plan Review and Steel Identification
We review structural and architectural drawings to identify which steel members are exposed (requiring intumescent) versus concealed (SFRM-eligible). This mapping is critical for accurate bidding and ensures the right product goes on the right steel from day one.
Surface Preparation
Steel surfaces must be clean, dry, and properly primed before intumescent application. We verify that the steel has been primed with a compatible primer per the intumescent manufacturer's requirements. Any oil, grease, mill scale, or contaminants are removed. Surface prep is where intumescent jobs succeed or fail.
Multi-Coat Application
Intumescent coatings are applied in multiple passes to build up to the specified dry film thickness (DFT). Depending on the required fire rating and steel configuration, this may be two to six coats. Each coat must cure before the next is applied. Our crews are trained to spray or roll intumescent coatings to achieve uniform coverage without runs or sags.
DFT Measurement and Documentation
After each coat cures, we measure dry film thickness using calibrated electronic gauges at multiple points per member. Every measurement is recorded and mapped to the structural grid. We self-test to the specified DFT before calling for third-party inspection, which means fewer failed inspections and no schedule delays for your GC.
Top Coat Application
Once the intumescent base coat has reached the required DFT and fully cured, we apply the specified top coat. The top coat provides UV protection, moisture resistance, and the finished color. Color matching to the architect's specification is standard. The top coat must be compatible with the intumescent product, and we verify compatibility before application.
Inspection Coordination
We coordinate with the third-party inspection agency, the GC, and the building department to schedule inspections. Because we self-test every area before calling for inspection, our first-time pass rate is exceptionally high. All DFT measurement records, product data sheets, and application documentation are provided in the final turnover package.
Why General Contractors Choose Andrex for Intumescent
Intumescent fireproofing is not a commodity trade. The applicator you choose directly affects the finish quality, inspection outcomes, and your project schedule. Here is why Colorado's top general contractors trust Andrex with their intumescent scopes:
Specialized Intumescent Crews
Our intumescent applicators are trained specifically for thin-film coatings. They understand the difference between SFRM and intumescent application techniques, and they deliver the architectural-grade finish quality that exposed steel demands.
38 Years, 7,500+ Projects
Since 1988, Andrex has completed over 7,500 fireproofing and insulation projects across Colorado and Wyoming. We have the experience to handle complex steel configurations and tight schedules.
Self-Testing Before Inspection
Every area is tested with calibrated DFT gauges before we call for third-party inspection. This practice virtually eliminates failed inspections, which means no re-work charges, no schedule disruptions, and no surprises.
Architectural Finish Standards
We understand that intumescent-coated steel is a visible finish in the completed space. Our crews apply coatings with the same care and attention to detail as a high-end paint crew, not a fireproofing crew.
Authorized Cafco Applicator
We are factory-trained and authorized to apply Cafco intumescent products. This authorization means the manufacturer stands behind our application and the product warranty is fully in effect.
BBB A+ Rated, Licensed and Insured
Andrex holds a BBB A+ rating, carries full insurance coverage, and meets all Colorado licensing requirements. We can provide a 2% bond when your project requires it.
Intumescent Fireproofing Service Area
Andrex provides intumescent fireproofing services throughout Colorado and into neighboring Wyoming. Our crews are based in Denver and regularly mobilize to projects across the Front Range and beyond. Primary service areas include:
For projects outside our standard service area, contact us to discuss availability and mobilization.
Intumescent Fireproofing FAQ
What is intumescent fireproofing?
Intumescent fireproofing uses thin-film coatings applied to structural steel that look like paint under normal conditions. When exposed to extreme heat (typically 400 degrees Fahrenheit or higher), the coating expands 20 to 50 times its original thickness, forming an insulating char layer that protects the steel from fire damage. It is also known as IFRM (Intumescent Fire-Resistive Material).
How does intumescent coating work in a fire?
During a fire, the heat triggers a chemical reaction in the intumescent coating. The coating begins to swell and expand, creating a thick, meringue-like char layer. This expanded char acts as thermal insulation, slowing heat transfer to the steel and helping the structural member maintain its load-bearing capacity for the rated duration, typically 1 to 2 hours depending on the product and application thickness.
When should I use intumescent coatings instead of SFRM?
Choose intumescent coatings when structural steel will be visible in the finished space, such as lobbies, atriums, restaurants, retail stores, and modern office designs with exposed beams and columns. SFRM (spray-applied fireproofing) is the better choice when steel is concealed behind walls, ceilings, or soffits because it costs significantly less and can achieve higher fire ratings. Both meet IBC code requirements.
What fire ratings can intumescent coatings achieve?
Intumescent coatings are UL-listed for fire ratings ranging from 1-hour up to 4 hours on structural steel columns, beams, and joists. Products like SprayFilm WB3 are rated for up to 4-hour assemblies, though the required dry film thickness (DFT) increases substantially at higher ratings. Your structural engineer and the project specifications will determine the required rating for each member.
Can intumescent coatings be color-matched to the design?
Yes. Intumescent coatings accept compatible top coats that can be color-matched to virtually any architectural color specification. The base intumescent coating is typically applied in white or off-white, and then a protective top coat in the desired color is applied once the intumescent has cured. This gives architects full control over the final appearance of exposed steel.
How thick is intumescent fireproofing compared to SFRM?
Intumescent coatings are dramatically thinner than SFRM. A typical intumescent application for a 1-hour rating on a heavy column might be 40 to 80 mils of dry film thickness, whereas SFRM for the same rating could be 3/8 inch to 1 inch thick. Higher fire ratings require thicker applications — a 2-hour rating may need 150 mils or more depending on the steel section. Even so, the thin profile makes intumescent coatings ideal for exposed architectural steel where you want the steel shape to remain visible and clean.
Do you serve projects outside Denver?
Yes. While our headquarters is in Denver, we serve commercial construction projects throughout Colorado and into Wyoming. Our crews regularly work in Colorado Springs, Boulder, Fort Collins, Aurora, and across the entire Front Range. We are also available for larger projects in surrounding states by arrangement.
Ready to Get a Bid on Intumescent Fireproofing?
Send us your plans and specifications and we will provide a competitive bid with fast turnaround. Whether your project has 10 exposed columns or 10,000 square feet of exposed steel, Andrex has the crew and experience to deliver.
Our Other Services
Andrex provides a full range of passive fire protection and insulation services for commercial construction across Colorado.
Spray-Applied Fireproofing
SFRM for concealed structural steel. Monokote, BlazeShield II, and other UL-listed products for 1 to 4-hour fire ratings.
Learn more →Firestopping
Through-penetration and joint firestopping systems for walls and floors. UL-listed systems with full documentation.
Learn more →Spray Insulation
Monoglass, K-13, and spray foam insulation for thermal, acoustic, and condensation control in commercial buildings.
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