Cracks in walls near doors or windows can indicate a problem developing with your home’s foundations. Another sign that something’s amiss beneath your house are floors that start to slope.
If the underlying structural issue is subsidence, your foundations are sinking because of unstable soil that’s probably become too dry or too damp.
One of two engineering procedures is typically used by Melbourne underpinning contractors – concrete underpinning or resin injection – to fix the problem by strengthening the base for your foundations.
Concrete underpinning is the more conventional method to fortify foundations – by extending the depth of the foundation into firmer soil.
It entails digging holes and pouring concrete into them. The concrete is then left to set, creating a new foundation beneath the existing one.
Concrete underpinning is commonly used for smaller jobs. Although a well tried and tested engineering technique, it can be a slow, messy and labour-intensive process. Another potential drawback is that the deeper soil may not be sufficiently solid.
Resin Injection Underpinning
A more contemporary but still proven method of underpinning foundations, resin injection involves drilling small holes into the ground around the foundations and filling them with eco-friendly resin.
The substance expands beneath the foundation and elevates it back into its correct position. The resin also compacts the surrounding soil to prevent expansion or shrinkage. As more resin is injected, it will gradually lift the house above.
Unlike concrete underpinning, resin injection is a fast process requiring little or no excavation.
On the downside, resin injection underpinning may not be cost effective if it turns out there’s a large gap under the ground, which may need a lot of resin to fill it.
Preventing Further Subsidence
Subsidence experts say resin injection holds several advantages over concrete underpinning, including:
- Lack of disruption.
They point out, though, that for small jobs, concrete underpinning could be the cheaper option.
Both concrete underpinning and resin injections by Melbourne underpinning contractors have been proven to be effective in stabilising the ground underneath a building to prevent further subsidence.