An introduction to lime - The Hempcrete Topic: Designing and Building with Hemp-lime - page 63

Limes can help to ensure a healthy indoor air quality in buildings, reducing the need
for powered air-conditioning systems.
Gypsum
At about the same time as cement took over from lime in mortars and renders, the UK saw
the use of lime in plastering almost completely replaced by gypsum.
The appeal of internal plasters made from gypsum (calcium sulphate, CaSO 4 ) instead of
lime was primarily their ease of workability and fine finish. Gypsum plasters had been
available for centuries, but were previously too expensive to be used anywhere other than
in the grandest houses. Industrial quarrying and mass production methods in the early
twentieth century, including the ready availability of cheap pre-cast gypsum plasterboards,
suddenly made gypsum plasters cost-effective in the post-war housing boom.