A gypsum-based composite structure is prepared from a slurry comprising a mixture
of calcium sulfate hemihydrate, a cellulose ether additive other than CMC and an
amount of water that is sufficient to form a slurry. The calcium sulfate hemihydrate
is hydrated by the water forming a wallboard core reinforced by the cellulose ether
additive. The concentration, viscosity grade and degree of substitution of the
cellulose ether are selected to give the composite improved nail pull resistance
and greater flexural strength.
