The reason for the crack is that different materials have been used in the new work, so it will always expand and contract differently to the rest of the wall.
Also wall starters were designed mainly for lateral restraint.
Ideally if the wall is clay brickwork, the wall should be toothed out, and brickwork used to rebuild the wall. On commercial jobs where different materials are used, such as a wall being built off a concrete pillar, then as ree suggested metal laths would be used. Also sand/cement instead of hardwall would be better.
Going to these lengths is less likely in small domestic jobs, as it increases the cost, and also there's no engineers around to pull you up for it.
However I've had some really good results repairing cracks bedding paper tape over the cracks and using Knauf fill and finish over the top. They've lasted years without any issues.
Also wall starters were designed mainly for lateral restraint.
Ideally if the wall is clay brickwork, the wall should be toothed out, and brickwork used to rebuild the wall. On commercial jobs where different materials are used, such as a wall being built off a concrete pillar, then as ree suggested metal laths would be used. Also sand/cement instead of hardwall would be better.
Going to these lengths is less likely in small domestic jobs, as it increases the cost, and also there's no engineers around to pull you up for it.
However I've had some really good results repairing cracks bedding paper tape over the cracks and using Knauf fill and finish over the top. They've lasted years without any issues.
