Subsidence Explained
If the ground underneath your property changes or becomes unstable due to dryer or wet weather your house may be at risk of subsidence. Any downward movement of the ground may cause your house to sink or in worst cases collapse. Thankfully it is rare for a building to collapse, but it certainly can be a large and expensive issue to rectify if not dealt with quickly.
What Causes Subsidence?
There are several factors related to changes in the ground under your property. Here are some of the more common changes:
Changes to the water table. If your house is built on clay soils, a lack of water can cause the
soil to shrink and stress your foundations. Changes of water table can occur after a prolonged dry spell or if vegetation or trees are sucking moisture out of the ground via their roots.
Pre-existing problems like an old well or trench or back fill can cause the ground to be unstable.
Underground water leaks or water running towards your house in rainfall times (this is the most common problem). It can cause havoc with the soil especially if it gets wet and then dries out repeatedly.
How to spot signs of subsidence:
New or growing cracks: One of the most obvious signs of subsidence is cracks appearing in walls. These may be visible inside or outside your home, either on plasterwork of interior walls or on exterior brickwork. Not all cracks are caused by subsidence, so pay attention to the thickness. If it is more than 3mm and located near doors and windows it should be investigated by a Structural engineer. East Coast Screw Piers can help with this service.
Windows and doors that stick: If you notice doors and windows are getting jammed it may be a sign your house is starting to sink.
Fixing the Problem
Subsidence underpinning is usually carried out by a trade professional who specialises in foundation works. It generally involves excavation work in the affected area outside the house. A number of Steel screw piles (determined by the Structural engineer) are installed below the footings sometimes to a depth of 2 to 5m deep and a bracket is secured under the existing concrete footing and a jack secures this in place. The hole is backfilled and that is the completion of works.
Selling your Property
After the completion of works by East Coast Screw Piers you will be issued with independent structural certification. This can be forwarded to any prospective buyers and will stay with the property.
Does insurance cover underpinning works?
If your subsidence is covered by earthquake or flood damage you may be covered. Generally if the problem is caused by any of the above, sadly you may not be covered.
Andy: 0428 241 402
Dylan: 0432 271 034
Location
487 South Bank Road
Tamban NSW 2441
Hours
Mon: 9am – 5pm
Tue: 9am – 5pm
Wed: 9am – 5pm
Thur: 9am – 5pm
Fri: 9am – 5pm
Sat: Closed
Sun: Closed