USG Structo-Lite® Basecoat plaster is USG's lightest and most highly insulated basecoat plaster and is ideal for locations where an aggregate is unavailable. USG Structo-Lite® basecoat plaster is mill-mixed, perlite aggregate gypsum that weighs half as much as sanded basecoat plaster and provides thermal conductivity. Covers - 140 sq-ft Gypsum Lath 89 sq-ft Metal Lath 109 sq-ft Unit Masonry sq-ft