Is my house still safe?
A construction nearby can be a stressful experience. Apart from putting up with noise and dust, a deeper concern is whether the construction activity can impact your house. Some common symptoms of impact are:
- Fresh cracks of walls
- Cracks in paved driveways and aprons
- Widening cracks of garden walls
More serious symptoms can be:
- Jammed windows or doors
- Tilted shelves and cupboards
- Water ponding where water could flow smoothly previously
- Backflow in gutters or drains
- Water pipe leakages
- Localised overflow in swimming pools
The foremost concern is whether the house is still safe?
As this involves structural integrity, the Professional Engineer (PE) is the qualified person to advise. However, he relies on accurate data to analyse the structural integrity, investigate the causes and develop the remedial action required. These accurate data can be provided by registered land surveyors using precise survey instruments and techniques. The collected data can also be used to support evidence in legal proceedings.
An excavation nearby without adequate protection installed can cause your land to subside. When the ground subsides unevenly, as is often the case, the floors and pavement become uneven. This can also lead to cracks and backflows in drains and gutters. Cracks on outdoor features get progressively larger.
In more serious cases, walls may tilt, not just crack. Objects can roll easily on their own on the floor or you worry that the book shelf may tip over.
The situation can be more complex when there is more than one sources of ground subsidence resulting in more than one direction of subsidence. This can be due to a myriad of factors. Accurate and refined measurements have to be made to help the PE identify the sources and intensities attributed by each.
Another element to consider is monitoring the subsidence over a period of time to check for continued subsidence. The changes derived from these periodic measurements will help determine if the soil has stabilised or is worsening.
Walls and columns can also be measured for tilts. The PE will need these parameters to establish the structural integrity.
To investigate cases of ground subsidence and structural integrity, the PE will need to work with the land surveyor. For legal proceedings, both the PE and the registered land surveyor can be called upon as expert witnesses in their respective proceedings.