Hairline cracks
Thin cracks in mortar joints are common and usually cosmetic. They let some water in, so seal them.
Watch for growth.
Stair-step cracks
Cracks that follow mortar joints in a stair pattern often point to settling or movement. Wider than a pencil line deserves a visit.
Mark ends with a date.
Horizontal cracks
These can mean soil pressure on a foundation wall or a failed lintel. They are more serious than vertical hairlines.
Do not ignore them.
Bulges and leans
A bowed wall is under load that it is losing. Keep people away and call.
Early repair is easier.
Monitoring
Mark and photograph cracks monthly. If they grow, call.
A simple tape gauge helps.
Causes and fixes
Drainage, trees, settling and rust all play parts. Fix the cause, then repair the wall.
Engineers help with big movement.
Mark every crack, watch for change and fix the cause of movement before the surface.
