10 × 25 = 250 m2 required in square feet As a result, the approximate square footage of insulating material required is 250m2. The depth of your insulation layer will determine the amount you need. If it's only 1/8 inch thick, you'll need about 5 yards; if 1/2 inch thick, 10 yards are required. The amount you need depends on the type of fiber that makes up the insulation. Cotton and wool fibers are long, thin, and delicate; they're best used in smaller amounts for their warmth-retaining qualities rather than their capacity to keep out cold. By contrast, glass fibers are short and stout; they provide strength and durability where other fibers may be weak. Glass-fiber insulation is commonly used in central heating systems and as roofing material. Other factors such as type of support structure, temperature extremes, etc. also play a role in determining how much insulation you need. For example, if you're building a wall with wood studs and drywall, you'll need more insulation than if you were building a wall with steel studs and paneling. In addition, if you're living in an area that experiences cold temperatures, you'll need more insulation than if you were living in a climate where heat is abundant.