Solutions for underpinning a house in Auckland

over time, pipes under a property may deteriorate, become damaged or blocked, causing cracks which allow water to seep into the ground, both around and directly underneath the property. This is very common with clay pipes found in homes older than 20 years.  Leaky gutters and downpipes or dripping outdoor taps are also frequently identified as the source of water collecting near house foundations.

moisture management is key for good foundation and footing maintenance. If the soil does not have adequate drainage, water will collect causing the ground to weaken and potentially cause the home to subside or ‘sink’.

Auckland receives a significant amount of rain, with rain falls in August 2019 breaking the record for the greatest number of consecutive wet days. After heavy rainfall often comes flooding and sodden backyards that don’t have a chance to dry out due to ongoing cold and wet weather conditions. If clay soils become oversaturated, the ground loses its strength and footings settle through the clay. This is when house re-piling or house re-levelling is required.

When building or renovation works take place at a neighbouring property, earthmoving and excavation can impact the stability of the soil on your side of the fence. This is even more problematic when coinciding with periods of heavy rain which soften the ground and may lead to soil erosion and voids.  Equally, the clearing of trees associated with development can affect the water table as moisture is no longer drawn out of the soil by the tree’s roots.

If pipes start to develop cracks or have loose joints, tree roots will naturally grow towards these areas in search for water. Eventually, aggressive root systems will infiltrate pipes causing blockages which result in water spilling into the ground, impacting soil and the stability of house foundations.

With many homes in the Auckland area dating back to the mid-1900s or earlier, it’s important to note that construction methods accepted at the time may contribute to foundation stability being compromised today. In some cases, a ring beam foundation will be smaller than is required by the current building code, which means changes in soil conditions over time, or the added weight of additions and renovations, may lead to structural movement.

In the mid-1930s, a ring beam – or continuous reinforced concrete perimeter foundation wall – was introduced to building construction to combat termite attack and accommodate movement caused by the reactive clay soils of Auckland. These foundations for typically timber-framed buildings are common beneath many older properties in this part of the city. However, these original foundations tend to be smaller than those found under more contemporary homes, making them more susceptible to seasonal movement. Renovations to the house over time, and neighbouring construction or excavation for a pool, may further contribute to ground movement and the need for house lifters in areas including Remuera, Newmarket, Parnell, Mount Albert, Mount Roskill

incorporating a number of coastal suburbs, and a range of older homes and higher density housing, this popular district has many pockets of reactive clay soils which noticeably contract and expand depending on moisture levels. The growth of infilling development in these urban areas, where single-storey homes are converted to two-storey dwellings or townhouses, can further contribute to cracks forming in the perimeter walls of established homes, either due to nearby construction or increased weight of building additions. Areas affected, where homeowners may be seeking house foundation specialist services, include Takapanu, Glenfield, Albany and Orewa Triangle.

featuring some of Auckland’s leafiest suburbs, many homes in this area are positioned on larger, steeper blocks which neighbour parks, bushland and the shorefront. Surface water management is important across larger backyards where rain may collect and run across a property, impacting soils and ground stability. During drought periods, tree roots may also infiltrate underground pipes seeking moisture, causing water leaks into the foundation ground and impacting shallower footings. Drain repair and drainage solutions may form part of the ground improvement recommendations in suburbs including Henderson, New Lynn, Kelston, Sunnyvale, Te Atatu South/Peninsula, Massey, Westharbour, Hobsonville and Titirangi.

this part of the city features many modern homes often built on a conventional concrete slab foundation, or what are known as raft or waffle slab foundations which were introduced in the 90s. Mainmark is a foundation specialist that can help to devise the best method of home foundation repair to suit each home, targeting unstable ground that may be contributing to subsidence. In newer areas, vibrations from development in neighbouring properties may also cause ground disturbance and aggravate cracking, often visible on internal walls and the brick veneer exterior. Areas affected by these conditions may include East Tamaki, Highland Park, Howick, Cockle Bay, Botany Downs, Dannemora and Pakuranga.