The thin blocks are solid and either square edged or with a tongue and groove in the short edges so that there is a mechanical bond between blocks to improve the stability of internal partitions. The
poor structural stability may be improved by the use of storey height door linings which are secured at floor and ceiling level.
Thin block internal partitions afford negligible acoustic insulation and poor support for fittings, such as book shelves secured to them.
The thicker blocks are either hollow or cellular to reduce weight and drying shrinkage.