Abstract: An extrudable gypsum plaster paste is disclosed comprising: &agr; gypsum plaster, water in a substantially stoichiometric amount; a binder; and a clay or another rheology modifier functionally equivalent to a clay. Such pastes can have a yield stress sufficient to make the paste self supporting. The invention also provides a method for making an extrudable gypsum plaster paste comprising: mixing &agr; gypsum plaster, water in a substantially stoichiometric amount and a binder; and mixing into that mixture a clay or other rheology modifier functionally equivalent to a clay.