Updated: Dec 14, 2018
Structural cracks can be caused by a variety of problems, which might include, but are not limited to:
•Damage due to damp •Crushed or decayed internal structural timber •Shrinkage of clay soils •Unstable adjacent walls •Lack of foundation •Temperature influence •Wind loads •Fractured masonry •Lowering of ground water •Road traffic vibration. •Air traffic •Damaged drains.
The crack may be caused not only by one of the above factors, but by a number working together to create subsidence, bowed walls, delaminated bricks and general deterioration of the masonry structure.
💡How to fix me : This can be patched in some cases, however if the plaster is pulling away from the lath, the section of the wall will need to be hacked-off, bonded then skimmed