Gypsum plaster
Jericho and Egypt used burnt gypsum.
Gypsum board · CaSO4·2H2O panels that buy fire time by calcining — the everyday A2/A1 lining of interiors.
Milestones in order. This is history, not a weekly activity grid.
Darker cells mean a higher score for this topic on that metric.
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Declared reaction class in this atlas: A2-s1,d0 typical; core A1. Assemblies still need resistance tests.
Thermal mark 34/100 versus the atlas. Conductivity note: ~0.17 W/m·K.
~700–1000 kg/m³
Origin story: Sackett 1894; US Gypsum 1916 (United States).
Circularity mark 62/100 — editorial, route-specific.
calcines ~80–180 °C (dehydration)
heat 54 · fire 92
Gypsum board did not arrive as a finished commodity. Sackett 1894; US Gypsum 1916 around United States still explains who makes it and which tests it sits in.
Ten dated points, five eras and three milestones below are the spine — not a complete industrial history.
Jericho and Egypt used burnt gypsum.
Paper-faced gypsum panels in the US.
US Gypsum brands the wall.
Speed over lath-and-plaster.
Glass fibres in core for fire assemblies.
12.5 mm as the module.
Green / blue boards, still not exterior grade.
European board types (A, F, H, D…).
Multiple layers for EI 60–120.
Closed-loop from jobsite offcuts in some markets.
Jericho and Egypt used burnt gypsum.
US Gypsum brands the wall.
Glass fibres in core for fire assemblies.
Green / blue boards, still not exterior grade.
Multiple layers for EI 60–120.
Speed over lath-and-plaster.
Green / blue boards, still not exterior grade.
Closed-loop from jobsite offcuts in some markets.
Knowing this timeline is how to read a mill certificate without treating Gypsum board as timeless.
DuPont’s meta-aramid — fire-fighter turnout, electrical paper and a char that does not melt-drip like nylon.
Overall 65 🧯Paints that swell into insulating char — the thin-film way to give steel an R-rating without bulky boards.
Overall 58 🌡️Spun refractory fibres for 1000–1400 °C — kiln linings, gaskets, and a respirable-fibre caution that AES grades try to ease.
Overall 62