What in the World is a Slab Leak in a Home?


House leaks are common with faucets, toilets and in-wall piping. However, a slab leak is another matter entirely. These types of leaks are particularly frustrating, especially given the fact that the house is sitting on top of the location and needs to be modified to get to the leak. However, unlike a wall, which can be cut open and then sealed up afterward, a slab leak is a bit more complicated.

Modern Home Background

For a long time, homes were built on stands. This meant that the entire house was built on a framework of beams that stood on cement shoes planted in the ground. This provided a separation between the house and the dirt below, allowed water and moisture to run through without damaging the home, and it allowed easy access to the bottom of the house for plumbing and wiring. However, somewhere around the 1970s, homes started being built on cement slabs, known today as foundations. These cement slabs had all the plumbing pre-installed which was secured in place as the cement dried and cured. The home was then built on top, and all the plumbing was connected to the pipes running through the slab. A slab leak is, literally, a leak in one of the pipes that sit in the cement foundation. So, given the fact that one has to open up the floor to get to the location of where the pipe is leaking and then break through the cement, the complications become apparent.

Fixing a slab leak is not a do-it-yourself or DIY job. This requires a good amount of knowledge about plumbing, cement, and flooring as well. The process involves finding the location of the leak, doing the necessary work to get to it, applying the repair, sealing everything back up and finishing the house flooring again. Some will argue just ignore the matter, but this is a mistake too. A slab leak allows water to spread out into the cement and leak. The foundation will be damaged and, when water has nowhere to go, it will rise up to the house flooring, causing more damage. It can also be a big source of toxic mold.

Why Do Slab Leaks Happen?

The causes include a variety of reasons, not all being preventable. They include:

  • Poor foundation work – The laying and curing of the cement or how the pipes were first installed was done wrong. Finding this out more than 10 years after the home was built is usually outside the home warranty period and the cost is on the homeowner or homeowner insurance to fix, usually.
  • House settling – the foundation and home weren’t quite built on solid ground and the earth moved more after the fact with weight on it. Enough movement can bend or break a plumbing line in the foundation.
  • Pipe corrosion – usually due to a poor choice of materials used, pipe corrosion can create leaks from failing plumbing lines. Again, warranty issues may have expired to cover the cost.
  • Friction – pipes can move around due to pressure changes, and the friction can create a wear spot or crack.
  • Age – old homes have more serious issues as their assembly starts to fall apart. Some of it can be avoided with maintenance, but a slab leak is not one of them.

The tell-tale sign of a slab leak is wet flooring without any other obvious cause for the leak. Cracks in the flooring and excessive moisture coming up are giveaways as well. Mold underneath the carpet is another sign of excessive moisture, as well as a loss of water pressure or hearing water moving in the house system when everything is turned off. The feeling of a hot or warm spot on the floor that makes no sense can indicate a hot water line leaking as well.

Professional Repairs

Slab leak services are a regular order for plumbers who work on modern homes. The problem occurs more often than people think, especially in neighborhoods with cement foundations as a common building practice. The cost tends to run in two faces, detection and then repair. However, additional costs can be incurred if the foundation damage is serious and has to be repaired to avoid structural problems for the home. In most cases, the issue can be addressed by a plumber with minimally invasive procedures to the foundation.

With a full diagnosis and detection, a plumber can provide the options going forward and what’s involved. Whatever the choice, don’t ignore the leak; it only makes the damage worse over time.