Buildings and buildings crack for many reasons. It has become acceptable to some builders to consider that cracking is inevitable and there is nothing that can be done. This is often WRONG!
Cracks in Walls
Firstly it is a common misconception that cracking to brick walls is always from settlement cracking and that it is expected in masonry (brick) buildings.
It is NOT.
Adequate preparation of the slab, identifying reactive soils, designing footing, isolation joints, control joints, slip joints, the omission of weep holes and much more will have a direct result on the amount of cracking to be expected.
Secondly not all cracking is the result of settlement and too often the cause is not determined or looked into at all!. Your builder may produce a table which states that certain cracks are acceptable without establishing why the cracks have occurred. Cracks in brick walls can be the result of heave, subsidence, the omission of brick articulation joints and other defective and often unacceptable building work. The Australian Standard for Masonry Construction states that masonry (brick work) must be isolated from differential building movement to control or resist cracking. When building components such as ceilings and walls are fixed together the tend to move. If there is no provision for movement, in accordance with accepted industry practice they will tend to crack or shear.
Cracked Tiles
Often ceramic tiles chip, become drummy or lift 2 or more years from construction. Most people contact their builder who usually states this is common and is acceptable in accordance with acceptable tolerance. It often is NOT. What the builder may not know is that floor tiles must be installed to allow for movement, just like brick walls should be installed to allow for movement. Two common building defects which result in cracked tiles, loose tiles or drummy tiles include omitting perimeter control joints and intermediate control joints.
Cracked Cornice
As in the above examples cornice must be installed to allow for movement. Australian Standard Gypsum linings in residential and light commercial construction— Application and finishing states that gypsum products (plasterboard, Gyprock etc..) must be installed to allow for differential building movement to resist cracking and control movement.
Cracked Ceilings
Ceilings crack often because they are installed in one continuous sheet over 9.0m long in any given direction. Australian Standard Gypsum linings in residential and light commercial construction— Application and finishing states that ceilings require control or movement joints to resist cracking. Another common defect is the omission of back blocking and insufficient fixings.
So if your building has begun to crack don't assume that it is natural or expected contact SHS to inspect and determine WHY your house may be affected by cracking, WHAT can be done to rectify and IF the cracks are Structurally Significant. There are many defective work practices that cause cracking to buildings and the Australian Standards, Manufacturer Installation Guides and The building Code of Australia are clear on how buildings may be constructed to resist or control cracking.
