Water Leaks Under Concrete Slabs and Floors

The location of some hot water leaks under concrete slabs can be found by the touch of a hand. The sound of bubbling water is also an indication of the proximity to a water leak.

If the leak is under a suspended concrete slab, it may be possible to undertake a visual investigation. As most concrete slabs are laid directly on the ground, a visual inspection to find the cause of the leak will not be possible.

Experience combined with electronic pipe and leak locating equipment is the best way to find the cause of water leaks under slabs. The right equipment in the hands of an experienced operator can make water leak locating 99% accurate.

Line tracers, acoustic listening devices, thermal cameras and small CCTV cameras make up the required equipment to find water leaks under slabs.

Water pipes under concrete slabs often leak. This is due to ongoing expansion and contraction caused by heat and cold. Water pipes may be wearing against rocks or bricks, reacting with the soil they are buried in, or have cracked joints. Other causes may be broken drainage pipes, poor drainage away from buildings, torn waterproofing plastic membranes under the slab, and the outside ground level being higher than inside floor level.

Water will seep up through concrete slabs if the plastic waterproofing membrane between the bottom of the slab and the ground is torn or has been incorrectly sealed. This will occur if there is a lot of water present under the slab and the air above the slab is warm. Note that garages and ‘non-inhabitable spaces’ do not require the installation of a plastic waterproofing membrane under the slab. You should speak to your builder if this occurs.

This depends on the nature of the leak. To fix a leaking water pipe under the slab, the concrete needs to be cut open. Because this can destroy floor coverings and puncture the plastic waterproofing membrane, smart plumbers prefer to bypass leaking sections of pipe.

This can often be done with minimal damage to the building. Torn slab membranes are difficult to repair, and you should consult your builder. To avoid damaging the slab and membrane, most drainage pipes under concrete slabs can be relined or diverted. External pipes can be excavated and repaired.

In some cases, landscaping is required to lower the external soil and extra drainage installed to prevent water becoming trapped under a building.

Insurance is designed to cover a loss. All insurance policies cover different types of leaks and scenarios. It is suggested that you read your insurance policy before you ring your insurer. Take pictures of any damage that is a result of the leak to show your loss. If you have a loss, the insurer will also likely cover the cost of investigations. In most cases your insurer will not cover the cost to repair a leaking pipe or torn membrane.