Quality noncombustible, moisture and mould resistant panels that core and snap easily and accept fasteners well. CGC Securock® Brand Glass-Mat Sheathing Panels are designed for use under exterior claddings where conventional gypsum sheathing products have traditionally been used, such as brick veneer, properly detailed Exterior Insulation Finish Systems (EIFS), clapboard siding, panel siding, shingle siding, shake siding and conventional stucco.