Fire resistance has always been an important part of the construction process. But building codes are also becoming stricter. Before, the biggest fire risk to the building was the kitchen. Yet we’re now experiencing situations where it’s getting hotter and dryer than ever, which means that buildings have a greater risk of fire coming from outside as they do a fire coming from indoors.
Stricter building codes means that there are more limitations on decorative materials that can be used to enhance your property. Unfortunately, many of the products that ARE available happen to be prohibitively expensive – like quarried stone and precast concrete. That is what makes architectural EPS such a viable solution.
About Architectural EPS and Fire Resistant Building Codes
Architectural EPS, or Expanded Polystyrene coated with a protective cementitious layer, is increasingly being used as a cost-effective alternative to heavier, more expensive materials.
Note that EPS alone is not naturally fireproof. But our products are not solely EPS. They are EPS, with a fire retardant additive, covered in additional fire resistant material. It is the system used in architectural applications that is specifically engineered to meet fire safety standards outlined in modern building codes.
EPS used for architectural details is typically encapsulated in a combination of fiberglass mesh and a cementitious, acrylic-modified coating. This outer shell provides a hardened, non-combustible barrier that prevents the EPS core from being directly exposed to flames or high heat. This protective layer is what allows the product to meet or exceed many of the fire rating requirements for use in exterior cladding and trim applications.
How Architectural EPS Performs in Fire Testing
Building codes reference several standardized tests to assess fire safety, including flame spread, smoke development, and ignition resistance. Properly coated architectural EPS products are designed to:
- Meet Class A Flame Spread Ratings – Independent testing under ASTM E84 (Standard Test Method for Surface Burning Characteristics of Building Materials) often shows that coated EPS achieves a flame spread index of 25 or less, which qualifies as Class A, the most fire-resistant rating available for surface materials.
- Limit Smoke Development – Cementitious coatings on EPS significantly reduce smoke generation compared to untreated foam or combustible plastics, meeting smoke developed index requirements under building codes.
- Pass NFPA 285 Testing in Wall Assemblies – When used as part of a complete exterior wall system, architectural EPS can be included in assemblies that pass the NFPA 285 standard, which tests flame propagation on multi-story buildings.
These results demonstrate that when architectural EPS is properly manufactured, coated, and installed within a tested system, it can comply with the increasingly strict fire-resistant requirements found in both the International Building Code (IBC) and regional code adaptations.
Advantages Over Other Decorative Materials
Because building codes are stricter than ever, property owners and architects often find their decorative options limited. Many traditional trim materials – such as quarried stone or precast concrete – meet fire standards but are heavy, labor-intensive, and costly to fabricate and install. Architectural EPS offers:
- Lightweight Installation – EPS is significantly lighter, reducing structural load and easing installation requirements without compromising on fire-rated coatings.
- Code Compliance at Lower Cost – When properly coated, EPS provides similar fire-resistance performance as heavier masonry materials, at a fraction of the cost.
- Design Versatility – EPS can be cut and shaped into detailed profiles that would be difficult or prohibitively expensive with stone or precast, allowing for greater architectural freedom while staying within code requirements.
Modern construction demands materials that balance aesthetics, cost-efficiency, and safety. Architectural EPS, when paired with certified fire-resistant coatings and installed according to tested specifications, meets the performance standards required under today’s stringent building codes. This makes it an attractive alternative to traditional decorative products, offering the look of high-end materials without sacrificing safety or budget.
