BS 8103-2 Structural design of low rise buildings – Part 2 Code of Practice for Masonry Walls for housing provides guidance on wall design, block and mortar strength, movement joints etc for housing for common layouts and for up to three storeys.
The recommendations in BS 8103-2 are intended to provide economic safe designs without the need for calculations of loading and strength criteria. Beyond this scope use Eurocode 6.
Note: to satisfy structural design, both block type and mortar type must be specified.