Methods of manufacturing composites are provided, including combining dihydrate calcium sulfate whiskers, hemihydrate calcium sulfate stucco, and water to form a slurry, and setting the slurry to form a composite having a natural porosity of about 60 volume percent or greater. Composites are also provided, including dihydrate calcium sulfate whiskers and dihydrate calcium sulfate crystals, and having a natural porosity of about 60 volume percent or greater.