The most durable joint type is the “ironed” joint. The ironing rod compresses the surface and enhances the bond, making it more weather-resistant.

Ironed joints (in M4 mortar) are mandatory in severe marine environments (AS3700, Clause 4.9.2). Alphalite masonry is ”Exposure grade” which is suitable for severe marine environments.

“Raked” joints are NOT suitable for hollow blockwork.