Slab heave is uneven movement of a house footing and slab.
Slab heave is often caused by reactive clay soils below concrete slabs expanding when they absorb moisture. The amount of moisture in the soil is usually influenced by one or more of the following:
- Excessive amounts of rainwater.
- Broken sewer, water or stormwater pipes.
- Poor site drainage and / or garden irrigation / design.
When reactive clay soils are exposed to moisture they expand and can place upward pressure on the underside of a concrete slab and cause different sections of the concrete slab to rise up, lift the frame of the house and in turn crack plasterboard ceilings, cornice and walls and cause doors and windows to stick and jam.
It is the uneven rising up of the concrete slab, often in different locations around and below the inside of the home, that causes the greatest damage to the structure of a new home including but not limited to the following:
- Severe cracking in ceilings, cornice and walls inside the home.
- Cracked floor and wall tiles and wide and uneven gaps appearing between floor and wall tiles.
- Windows and doors that are difficult to open and close.
- Completely jammed windows and doors.
Temporary plastic downpipes should be installed between all gutter outlets and the stormwater riser pipes during the entire construction process so that rainwater does not pond at the base of concrete footings or around the perimeter of the concrete slab.
While slab heave can be rectified, it is usually very expensive and often not successful. Sometimes, the only way to rectify serious slab heave is to completely demolish the home and to rebuild a new one.
Before going down the path of engaging very expensive structural engineering firms and legal firms it is often worth engaging an experienced building consultant to carry out a thorough and completely independent assessment of the full extent of the slab heave and consequential damage to the structure of the home.
If you would like to discuss the impact that slab heave has had on your new home or arrange for your defective home to be thoroughly inspected and a detailed report on the full extent of the damage to be prepared, please contact Mr. Peter Limburg, Director at Finalinspect on 0408 132 152