GLASS MAT admin May 18, 2018 May 31, 2018 GLASROC® SHEATHING GlasRoc® Brand Sheathing High-Performance Exterior Sheathing* with EGRG Technology. Available in 1/2″ (12.7 mm) and 5/8″ (15.9 mm) Type X Long term protection to weather exposure LEARN MORE [see more drywall products]