Gypsum blocks are available with densities ranging from 600 to 1500 kg/m3, in thicknesses from 50 to 100 mm. The maximum thickness to BS EN 12859: 2011 is 150 mm. The preferred face dimensions are 666 mm in length and 500 mm in height, with a maximum length of 1000 mm. Gypsum blocks are classified by density and water absorption.

Gypsum blocks – density class:

Low density (L) 600–800 kg/m3
Medium density (M) 800–1100 kg/m3
High density (H) 1100–1500 kg/m3

Gypsum blocks – water absorption class:

H3 > 5%
H2 < 5%
H1 < 2.5%

The standard BS EN 15318: 2007 details the sound insulation properties of gypsum block partitions in relation to wall thickness and block density. Gypsum blocks may be used as non-load-bearing partitions and internal insulation of walls. They are assembled with gypsum-based adhesives as specified in BS EN 12860: 2001.