Microstructure features of gypsum wallboard made with high starch and high dispersant level

A lightweight gypsum wallboard comprising:

• a set gypsum core formed between two substantially parallel paper cover sheets, the set gypsum core having voids generally dispersed throughout the set gypsum core, the voids having walls with an average thickness about 70 to about 120 microns, in which the set gypsum core is made from a gypsum-containing slurry comprising:
• water, stucco, pregelatinized starch present in an amount of about 3% by weight based on the weight of stucco, a 45% by weight aqueous solution of a naphthalenesulfonate dispersant present in an amount of about 1.5% by weight based on the weight of stucco, sodium trimetaphosphate present in an amount of about 0.3% by weight based on the weight of stucco, and glass fiber present in an amount of 0 to about 0.2% by weight based on the weight of stucco, and soap foam,
• wherein at least one cover sheet is high tensile paper,
• wherein the set gypsum core has a density of about 29 pcf,
• and wherein the wallboard has a dry weight of about 1200 lb/MSF for a 1/2 inch thick board,
• a nail pull resistance of at least about 77 lb/MSF, and a core hardness of at least about 11 lb/MSF.