Causes of Subsidence
Excessive changes in the moisture conditions around the perimeter of your house can cause the footings to move, potentially causing damage to you house. Storm water systems can be your best defence against excessive changes in moisture levels. It is therefore important to avoid a blocked stormwater drain.
When to be worried about subsidence
Cracks in walls less than 1mm wide that are caused by movement of the footings are generally considered part of the normal movement that a house may experience and within an accepted range. Cracks more than 5mm wide are considered significant and outside the tolerances for footing movement.
Prevent significant soil moisture changes:
Well drained foundations will ensure normal soil moisture levels and maintain adequate bearing capacity of the footings. Below are some tips to help protect your house from damage caused by excessive movement of footings:
- Maintain your drainage and storm water systems with regular cleaning. A blocked stormwater drain will prevent water from escaping and promote excessive moisture levels.
- Slope soil, paths and garden beds away from the building. Large paved areas should have a storm water collection pit.
- Install garden drainage systems or drains against your external walls to remove excess moisture to your storm water system.
- Don’t excavate close to buildings footings. If you do need to do excavate next to your house, make sure you don’t excavate deeper than than the base of the footing. You must ensure you don’t undermine the footing.
- If you need to rehabilitate pipe work close to the foundations of your house, we recommend pipe relining instead of excavating so you don’t disturb your foundations.
- Don’t place garden beds along side the house.
- Be aware of trees close to the house as these can significantly impact the foundations and damage can occur months after you remove a tree.
- Roofs and gardens sheds should have gutters draining to your stormwater system.
If you need to find out more about our plumbing, drain clearing or pipe relining services please don’t hesitate to contact us on 1300 358 434 or contact us here. Alternatively you can read about the pros and cons of excavation versus relining.
Sourced from The Victorian Building Authority