Gypsum
Gypsum is a soft sulfate mineral with the chemical formula CaSO4·2H2O, also known as calcium sulfate dihydrate. It is comprised of calcium, sulphur bound to oxygen, and water. Natural gypsum is an abundant mineral in sedimentary rocks that has been mined and used for construction and and as a fertilizer since the time of Ancient Egypt.
More recently the term synthetic gypsum is used to describe gypsum that is manufactured or that forms as a by product of other processes, such as flue gas desulphurisation (FGD) gypsum which forms in coal-fired power stations.
Pure gypsum is typically white, although impurities create a wide range of different colours. Gypsum is moderately water soluble but exhibits retrograde solubility, meaning it becomes less soluble at higher temperatures. It is fire resistant and is effective at preventing the passage of sound.
In terms of production, gypsum rock is mined or quarried and then crushed and ground into a fine powder. A process of calcining heats the powder, driving off most of the chemically-combined water. The two other forms of gypsum are called selenite and satin spar.
This base gypsum is used for a wide variety of applications:
- Plaster, plasterboard, wallboard, and so on.
- Blockwork.
- Mortar.
- Blackboard chalk.
[edit] Related articles on Designing Buildings
Featured articles and news
The 5 elements of seiri, seiton, seiso, seiketsu and shitsuke.
Shading for housing, a design guide
A look back at embedding a new culture of shading.
The Architectural Technology Awards
The AT Awards 2025 are open for entries!
ECA Blueprint for Electrification
The 'mosaic of interconnected challenges' and how to deliver the UK’s Transition to Clean Power.
Grenfell Tower Principal Contractor Award notice
Tower repair and maintenance contractor announced as demolition contractor.
Passivhaus social homes benefit from heat pump service
Sixteen new homes designed and built to achieve Passivhaus constructed in Dumfries & Galloway.
CABE Publishes Results of 2025 Building Control Survey
Concern over lack of understanding of how roles have changed since the introduction of the BSA 2022.
British Architectural Sculpture 1851-1951
A rich heritage of decorative and figurative sculpture. Book review.
A programme to tackle the lack of diversity.
Independent Building Control review panel
Five members of the newly established, Grenfell Tower Inquiry recommended, panel appointed.
Welsh Recharging Electrical Skills Charter progresses
ECA progressing on the ‘asks’ of the Recharging Electrical Skills Charter at the Senedd in Wales.
A brief history from 1890s to 2020s.
CIOB and CORBON combine forces
To elevate professional standards in Nigeria’s construction industry.
Amendment to the GB Energy Bill welcomed by ECA
Move prevents nationally-owned energy company from investing in solar panels produced by modern slavery.
Gregor Harvie argues that AI is state-sanctioned theft of IP.
Experimental AI housing target help for councils
Experimental AI could help councils meet housing targets by digitising records.
BSRIA Occupant Wellbeing survey BOW
Occupant satisfaction and wellbeing tool inc. physical environment, indoor facilities, functionality and accessibility.
Comments
Please note the requirement for ensuring that gypsum products are correctly disposed of, it should not be mixed with biodegradable waste at a standard landfill site. It is possible to recycle the material.