Wall cracks are common in Australian houses and though some are nothing to worry about, others can indicate sinking or damaged foundation. Turning a blind eye can result in missing the warning signs for serious and ongoing structural damage. If the cause of wall cracks is not identified and addressed, the damaged foundations can quickly devalue a property. Generally, smaller hairline cracks are not cause for concern. These are usually the result of seasonal expansion and contraction of clay soils beneath the house resulting in minor foundation movement. These types of cracks can be easily patched and re-painted.
However, larger cracks that display the following characteristics may indicate a weakness in the property’s foundation: one side of the wall is higher than the other; doors and windows no longer close in their frame; cracks are wider than about 5mm. Problematic wall cracks will typically start at windows, doorways or house corners.
Large cracks may appear because the property’s foundation has shrunk or lost its strength, causing all or part of the house to sink. This usually happens because the moisture in the soil beneath the settled section of the home is either too wet or too dry. The CSIRO’s Homeowner’s Guide is a great resource for understanding why a home may move and how to manage the soil beneath its footings. The Queensland Building and Construction Commission also offers valuable advice.
The best long-term solution for fixing large cracks is to lift, re-level and re-support the home. This process is called “underpinning”. As the house is elevated to a level position, the cracks may close or become smaller. Plaster or render walls can then be patched and repainted. Windows and doors will also usually begin to work properly again.
A modern, innovative alternative to traditional concrete underpinning is Uretek® resin injection [Mainmark Company]. A lot like keyhole surgery, an expanding Uretek® resin is injected into the home’s foundations through relatively tiny holes [usually 16mm, but as small as 6mm if used inside the house]. The resin expands to fill voids and compacts soft ground, exerting controlled pressure to raise the home back towards a consistent level. The process is very specific and carefully controlled using laser technology. This method can be a good option because it: rarely takes more than a day; doesn’t require home owners to move out; involves no digging [therefore no mess]; can be completed around furniture and floor coverings; may be carried out from outside the house, so it doesn’t interrupt day to day life.
Uretek® resin injection technology complies with all local, state and national Building Code requirements. Watch this video to see how it works: https://www.youtube.com/watch?v=lr4GE4EOJlw
Uretek® resin injection
T: 1800 623 312