Which is a common material used in fire-retardant treatments for structural wood?

Mineral salts are commonly used in fire-retardant treatments for structural wood due to their effectiveness in reducing flammability. When applied to wood, these salts create a chemical barrier that inhibits combustion by forming a char layer when exposed to high temperatures. This char layer acts as insulation, slowing down the heat transfer to the wood beneath and thereby delaying ignition.

The use of mineral salts is particularly advantageous because they can not only enhance the fire resistance of wood without significantly altering its appearance but also allow the wood to retain much of its original strength and structural integrity. This makes them a preferred choice in the construction industry where safety standards regarding fire resistance are critical.

In contrast, polyurethane and epoxy resins are more often associated with coatings and adhesives than with fire retardance. While silicates can provide some fire retardant properties, mineral salts have become a standard due to their widespread acceptance and proven efficacy in wood preservation treatments.