Underpinning / Concrete Push Piers
Precast concrete cylinders are pushed into the ground with a hydraulic jack using the edge of the slab foundation as a fulcrum. The cylinders are stacked on each other, one by one and pushed into the ground until a point of refusal is reached.
The stacking of the cylinders creates a “pier”. After the piers are set the next is to add blocks between the pier and the slab. The foundation is slowly raised using jacks and steel shims are placed between the block and the foundation. The holes are then reinstated using the excavated soil.
This method is a preferred alternative to traditional underpinning and is ultimately quicker as it negates the requirement to have concrete mixed on or delivered to site.
Grace Foundation Solutions are the only supplier and installer of concrete push piers in NZ. Once again we lead the way in foundation repair solutions.
Screw piles are used extensively in NZ on commercial projects to stabilise the ground. Grace Foundation Solutions can install screw piles on your commercial or residential property.
Used in the slabjack system, the screw piles are inserted into the ground temporarily, once the foundation has been lifted and levelled the screw piles are then removed.
In Christchurch we installed permanent screw piles inside and outside dwellings for earthquake strengthening. In Auckland we have installed them inside and outside to stabilise the dwelling.
This means that once the screw piles are installed a modular or kitset home can be placed on the foundation or building can commence within a day or 2. The screw piles can be installed in almost any weather or limited access situation with minimal noise and environmental disturbance.
There is no digging or concrete required and they are completely removable and reusable.
Haven’t heard of screw piles?
Also called Helical Piers the first recorded use of one was in 1836 by Alexander Mitchell. He was looking for a solution how to better found marine structures on weak soils, such as sand reefs, mudflats, and river estuary banks.
In 1853, Eugenius Birch started using Mitchell’s screw pile technology to support seaside piers throughout England. The first of these was the Margate Pier. From 1862 to 1872, 18 seaside piers were constructed on screw piles.
During the expansion of the British Empire, screw piles were used to support new bridges on many continents.