What are the causes and which cracks are problems?
Types of Cracks
A. Horizontal cracks in walls
B. Vertical cracks in walls
C. 45 degree cracks
D. Cracks in ceramic tile floors
E. Cracks in plaster ceilings
A basic rule of thumb for approximately 80% of the wall cracks seen in residential structures can be broken down into three types: horizontal, vertical and 45 degree cracks.
A. Horizontal cracks are typically structurally related, however, their significance depends on whether there is lateral movement or not. If a wall has moved 1/3 of its thickness out of plumb, it is in imminent danger of falling. If it has not moved or if the movement is less than 1/3 of its thickness, the wall can probably be reinforced.