A rigid insulation board constructed by laminating a high-thermal-resistance foam, like polyisocyanurate or polystyrene, to a durable facer board such as wood fiberboard or perlite. This combination provides both high insulation value and a tough, heat-resistant top surface that can withstand hot asphalt application or heavy mechanical fastening.
We're using composite board insulation on this deck so the hot mop doesn't melt the polyiso.
Always install the composite board with the high-density facer side up to protect the foam core from hot adhesives and foot traffic.
Do not mix it up with
- Cover board: A cover board is a separate, single-material protective layer placed over insulation, while composite board has the protective layer factory-bonded to the foam.
Related terms
Cover board
A thin, rigid board installed over roof insulation to protect it and provide a solid substrate.
Hot mop
Waterproofing built from layers of felt mopped down with hot asphalt, or the act of applying it.
Single-ply roof
A roofing system that relies on a single layer of flexible synthetic membrane to provide waterproofing.