A composition for a slurry for manufacture of a building panel includes
one or more fillers, one or more binders and water. One or more fillers
is an expanded perlite at least partially covered with a film-forming,
thermoplastic polymer coating Some embodiments use calcined or uncalcined
gypsum as a binder or filler. One embodiment is a building panel that
includes a solid matrix of calcium sulfate dihydrate crystals bound to
expanded perlite.
A method of making the panel includes acquiring expanded perlite and
coating it with film-forming, thermoplastic polymer coating. After the
expanded perlite is prepared, it is combined with water other optional
fillers and one or more binders to form a slurry. The slurry is shaped
into a panel and allowed to dry.