Your Ultimate Guide To Residential Underpinning And The Different Techniques Used

Properly designed foundations will last a lifetime. However, several issues can compromise your foundation's structural integrity over time. Actively occurring subsidence, an increase in loading from a change in service loading, addition of more storeys, etc., and uneven settlement caused by tree root action, soil action, erosion, seismic activity, flooding, drought and more are some of the major causes of residential foundation problems. Underpinning is a process that aims to strengthen foundations that have been weakened and destabilised by such issues. Therefore, it can save you a great deal to consider residential underpinning if your home is a good candidate for one. However, the process can take various forms, and here are some of the primary techniques used.

Concrete Underpinning

Also known as mass concrete underpinning, mass pour, or pit method, it is one of the most frequently utilised residential underpinning techniques. As the name implies, it entails digging holes underneath your existing weakened foundation in sections and filling these sections with additional concrete. It extends your old foundation, providing much-needed extra support. Concrete underpinning is highly effective, especially for shallow foundations. It's also simple and allows for continuity of your home's use because you may not need to look for alternative housing as concrete mass pouring continues. In addition, concrete underpinning is perfect for resisting heavy foundation loads. However, because of its design, it can be disruptive and time-consuming, so keep that in mind when assessing different residential underpinning methods.

Mini Piling

Mini piling is another underpinning method to consider for strengthening your home's foundation. As the name suggests, it involves driving or boring down piles through your foundation's weaker soil to bedrock or a level of stronger and more stable soil. This enhances your foundation's stability, allowing it to support heavier loads more efficiently. It's one of the least disruptive underpinning techniques, allowing for quicker containing of the work area. Mini piling is also perfect for adverse soil conditions (like waterlogged and clayey soils) and areas with limited access. On the downside, it can be expensive because of the expertise required.

Beam And Base Underpinning

This is another underpinning technique worth considering. It's a more advanced method of foundation underpinning than the conventional concrete underpinning. First, metal or reinforced pre-cast concrete beams are constructed below or above to replace your existing footing. Mass concrete bases are then placed in predetermined load-bearing sections, allowing the beams to transfer your building's weight onto them.

Beam and base underpinning comes with high load-bearing capability. It's also faster than the traditional concrete underpinning technique. However, like the conventional method, it can be uneconomical if your existing foundation is relatively deep.