Geerco water absorption test results are based on total immersion of the test samples, in water, for a period of 24 hours.
Absorption of Geerco bricks (by weight)
Minimum Maximum Average
Sandlime Bricks 7% 13% 10%
Two important factors which affect the water absorption rate and therefore the resistance to water penetration are the size and distribution of the brick pores. The pores in the bricks are so numerous and consistent that the complete filling of each pore is unlikely. This limited porosity can be advantageous.
The linear Coefficient of thermal expansion for calcium silicate bricks is about (0.000008 to 0.000014) per degree celcius for vertical direction, and 0.0000056 per degree celcius for horizontal direction.
Geerco bricks comply with the shrinkage requirments of BS 187 ranges between 0.01% to 0.035%
Virtually all building materials expand or contract and bricks of all types are no exception. Such minor movement is, if necessary, easily compensated for in the correctdesign, storage and use of the material, and is not considered synonymous with cracking in brickwork.
The drying shrinkage of bricks situated in permanently damp conditions, below d.p.c, for example, is of no significance