How To Find and Repair Concrete Slabs That Leak


A slab leak is an industry term for a leak within the waterline piping below the concrete floor. Slab leaks are an issue in homes and buildings of all ages. They can also develop into a costly and inconvenient endeavour.

From our previous post how to find & detect water leak in walls in this post we will talk about concrete slabs. How to identify if your slabs have water leak, how to find and how to repair it.

slab leak symptoms

Faucet turned off but sound of water persists

This is a common indication of a leak. It needs locating with non-destructive methods utilising modern technology. This includes approved electronic amplification equipment supported by electromagnetic pipeline locators.

Related: Equipment for water leak detection in Melbourne

Floor hot spot could show hot water line leak

A “spot repair” involves creating an access point into the slab at the point of the determined leak. This is done in order to make a repair to the leaking pipe. It is recognised as a cost-effective repair option for more recent constructions.

For older systems, re-piping or re-routing the entire line that was leaking is considered the most effective method. For leak location purposes, highly trained technicians may employ non-invasive detection equipment to accurately determine the location of the leak. This saves you time and avoids needless property damage.

damp carpet

Mildew or excessive moisture under carpets

A damp carpet or rug with the presence of mould or mildew, accompanied with a peculiar odour could be one of the first indications of a cracked slab. This will require the floor covering to be lifted and an inspection must be carried out in the event of a concentring moisture presence.

cracks slab

Cracks in the walls or flooring

The appearance of cracks in your walls or flooring can be due to the saturation of the foundation, causing moisture to start leaking into the house. This can result in the foundation cracking or buckling.

In which case, you could also observe cracks in the foundation on the outside of the building.

Wet baseboards

Should you encounter wet baseboards then it could be the result of pressure on the foundations. Any crawl space or basement home built on clay soil can experience soil movement that adversely affects foundation. When saturated with excessive water clay soils expand and then contract when dry. The continual swelling and shrinking create pressure on the foundation. And if the foundation cracks, moisture can enter the home. As the floor joist weakens, the flooring above can sag. Moisture attracts various insects such as silverfish, millipedes, and centipedes.

Water coming out below the water heater

Any leak in your water heater is not intermittent. Due to the tank always being full, a leak will distribute water all around the outer lining of the tank. Generally, it is an issue related to water condensing, with a leak becoming obvious when access panels are removed.

Water on the floor or wet carpet

A wet carpet is a strong indication of a leak. If it concerns water on a tiled floor, then it could be sufficiently severe to cause water to gather in the space between the adhesive and the tiles. There may also be other indications in the case of hardwood floorings, such as a raised (dome shaped) or warped section. This is a sign that could warn you of serious damage regarding the foundations.

High water bills

A well above average water bill is a general sign of a leak in your home. Although it could be an indication of a water leak from the pool, but it could also be warning you of a leak under the slab. Therefore, if after preliminary checks have been completed without discovering the source, seek professional help.

Wet planters near the house

Any type of wet source against a house is a serious issue, as it can be the cause of damage to foundations and termites. You should ensure that the ground is graded away from the walls. And if you have any doubts, consult a professional. If there is a grading-related drainage issue, seek qualified help to have it corrected.

finding your slab leak

Check your water meter

Severe or combinations of minor water leaks can sometimes be detected by performing a simple leak check. After turning off all water supply sources, record the reading of the water meter and following a static wait of at least 15 minutes, check the water meter again. Should there be a recorded water usage during this period, then there is the likelihood of a leak?

Locate your house’s pipes

Knowing the location of main water supply is as important as an awareness of where to turn off or reset an electric breaker. Your home should have a main water shut-off valve installed inside, in the case of emergency situations and repairs. However, it is also worth taking a tour through your home and making note of how the plumbing system is structured.

Perform an initial pressure test of your home

Testing the water pressure in your home can be easily completed, with an inexpensive pressure gauge. Testing the water pressure periodically can help pre-empt a problem before a high pressure can damage the plumbing.

Perform complete electronic leak detection service

There is special, non-invasive equipment, available for the purpose of definitive diagnoses regarding water leaks in your home. Electromagnetic pipeline locators, electronic amplification equipment, and camera inspections like drainage cctv, are all examples of devices employed in the detection and location of a leak(s) beneath your foundations.

slab leak repair

Spot repair

This type of leak repair involves an excavation of up to 1m² to repair the section of leaking pipe. Although this may be a cheaper option, but if the pipe is in a poor condition, a repair may only provide a short-term solution.

Re-pipe or Reroute

The occasion can arise whereby it is necessary and even more cost-effective to re-pipe or reroute due to a slab leak that is not accessible to repair. This could include a water leak under a bathtub, shower unit or beneath a kitchen cabinet.

Epoxy pipe coating

The epoxy coating process is simple. However, it offers highly effective pipe restoration technology that coats the inside of pipes completely. The end result means that you will never have to be concerned about pin-hole leaks, weak water pressure, and pipe corrosion or contaminants filtering into your water supplies.

Direct Access

The responsibility related to the pipework that conducts clean water is shared between water companies and property owners. The former maintain up-to-date plans of the sewers and water mains for which they are responsible. However, the majority of pipes within individual property boundaries are the responsibility of the property owners. It is, therefore, incumbent upon them to maintain those pipes and ensure adequate and safe access to them.

Plumbing services

There are plumbing services  and leak detection in Melbourne that employ highly trained and qualified technicians to conduct leak detection and repair. They will use non-invasive leak detection equipment to accurately locate leaks. Thereby, they provide a service that avoids unnecessary property damage.