Different Grades of Gypsum

Gypsum comes in various grades of quality and it is worth investigating what each supplier is offering to compare apples with apples.

Gypsum products are generally Graded into the following categories:

• Grade 1 Gypsum – contains >15% Sulphur (S) and >19% Calcium (Ca) – aka Grade A gypsum
• Grade 2 Gypsum – contains >12.5% Sulphur (S) and >15.5% Calcium (Ca) – aka Grade B gypsum
• Grade 3 Gypsum – contains >10% Sulphur (S) and >12.5% Calcium (Ca)  – aka Grade C gypsum