12.7mm thick black Ground nstruction mats export-High Quality Ground TECHNICAL GUIDE – Georgia-Pacific Building ProductsDensGlass Sheathing is available in 1/2” (12.7 mm) thickness and DensGlass Fireguard Sheathing is available in 5/8” (15.9 mm) heavy duty plastic nstruction mats 12.7mm thick for architecture Ground Protection Mats Temporary nstruction Site Equipment Discounts on 12 Mats.