For intumescent fireproofing to be effective, the substrate (often steel) must be clean and properly primed. We begin by removing any rust, mill scale, oil, or old paint from the steel, typically by abrasive blasting or power tool cleaning, depending on project needs. Then we apply a compatible primer specified by the intumescent coating manufacturer to ensure good adhesion and to prevent corrosion under the coating.

Intumescent coatings we apply are rigorously tested and rated to provide up to 2 or 3 hours of fire resistance depending on the product and design. When a fire occurs, these coatings will react around ~350-400°F by foaming up to many times their original thickness to form a char barrier. This insulative char keeps the steel (or wood) cooler much longer, preventing early collapse or structural failure. By slowing the transfer of heat, intumescent coatings help maintain the building’s structural integrity during a critical window, allowing more time for evacuation and firefighting efforts.

Intumescent coatings are applied in multiple layers to build up the required thickness. We utilize airless spray equipment or special trowels/brushes for smaller areas, applying coats to reach the necessary dry film thickness that correlates to the desired fire rating (for instance, a thicker coat for a 2-hour rating than for a 1-hour rating). Our team is trained to measure wet and dry film thickness using gauges to verify that the proper amount of material has been applied uniformly. It’s crucial that the coating is even, without thin spots, to perform correctly in a fire. We also take care to protect surrounding areas from overspray and maintain environmental conditions (like temperature and humidity) as recommended during curing.

We can also apply intumescent coatings to other substrates if needed – for example, to achieve fire-resistance on exposed timber beams or on concrete that needs an aesthetic fireproof layer. There are different formulations (water-based, solvent-based, epoxy intumescents) for different applications, including exterior steel. We select the appropriate type for each situation, considering factors like whether the steel is outside (needing weather resistance), subject to wear, or in a high-humidity area.

One advantage of intumescent coatings is that, unlike bulky cementitious fireproofing, they yield a smooth finish that can be painted over for aesthetics. After the intumescent layers have cured, we can apply a topcoat in any color or sheen you desire (or the manufacturer’s specified topcoat for exterior exposures) to blend the steel into the building’s design. This is popular in spaces where exposed structural elements are part of the architectural look (lofts, modern offices, etc.), as you get fire protection without compromising on appearance.