We recently went through this as well with a slab leak in a 40 year old house next to the master bath. Yes, there are two options: cut into the slab and directly patch the pipe, or abandon that line and pipe around it in the attic (aka repipe).
The cost to repipe a house runs anywhere from $1,500 to $15,000, but most homeowners pay around $7,500. Costs are considerably lower to repipe a single fixture.
Main supply and sewer lines are placed in the ground and sticking up before the slab is poured. Some will run all of the supply lines under slab. I prefer running them in the walls and ceiling, because that is much easier to access in case of a leak. I like to keep as little plumbing under the concrete as possible.
The traditional way of installing plumbing would be to cut through your concrete slab so you can lay the plumbing and connect it to your existing sewer point. This will give you the most seamless result, and the end result will be similar to if you had laid it in the slab from the beginning.
Move Plumbing in a Concrete Slab
This project's total cost with materials is between $550 and $1,500, depending on how thick the slab is, how buried the plumbing is, and the plumbing type.
If your home is undergoing a renovation or remodel, you may want to consider repiping a house built on a slab during the construction project. It's easier to replace pipes inside walls before hanging drywall. Brass and copper pipes tend to last 80 to 100 years. Galvanized steel may only last 70 to 80 years.
When a water pipe leaks or bursts under the concrete foundation, this is a slab leak. Often, a homeowner does not even realize water is leaking under and around the slab. These leaks can cause a list of problems, and eventually, the damage can evolve into structural instability and collapse.
You would have to raise the floor about 12" to 18" to put the plumbing on top of the slab. The plumber will have the floor cut and put the piping under the concrete.
One misconception we'd like to clear up first, though, is there are no pipes IN the concrete slab. And this means there can't be a leak within the foundation. In most cases, the pipes are under the slab.
A majority of the time, homeowners insurance policies do not cover whole house repiping. Insurance policies are designed to cover unexpected problems. For example, if you have a pipe burst, then your homeowners' insurance may cover the cost of repairs due to the water damage.
Compared to copper piping, which would cost $8,000 – $10,000 to replace in a two-bathroom home, PEX would only cost on average $4,000 – $6,000 – offering significant cost-saving opportunities. PEX is also a flexible plastic hose that can be snaked into walls with minimal damage.
Repiping is the preferred method for repairing slab leaks because it prevents the recurrence of slab leaks in the future. Since the pipes under your slab are no longer being used, there is no longer the risk of a leak damaging your foundation, as well as the rest of your home.
And repiping a whole-home can be a somewhat intrusive job; there's usually a team of licensed plumbers using tools, getting on ladders, and carrying equipment through your home— not the ideal setting for a family dinner, or even a quiet night to yourself after a long day of work.
Trenchless pipe lining, or cured-in-place pipe (CIPP) lining, is a non-invasive way to repair damaged pipes. This innovative technique involves inserting a flexible liner coated with epoxy resin into the existing pipe. It cures in place within a day.
If Your Bathroom is On Top of a Concrete Slab
To move the toilet more than just a couple of inches, you will have to demolish the concrete to access and relocate water and waste lines. Then you will have to rebuild the concrete foundation and replace the sub-flooring, flooring, and fixtures.
The best way to tie in a new slab is to drill into the edge of the existing slab at least four inches, and grout in short lengths of rebar, which will extend into the new slab. This will prevent differential movement between the slabs.
If the slab leak resulted from a pipe that suddenly burst, homeowners insurance may pay for the removal and replacement of the slab. Foundation leaks caused by a flood generally won't be covered by a standard homeowners policy.
Vertical or diagonal cracking can sometimes indicate foundation settlement. However, other signs and symptoms of foundation problems would have to be present for this to be a concern. If there are no other signs around the home, then it's likely just a cosmetic imperfection.
Excessive Rain Occurs on Top of Poor Drainage
So the excess water will create extra pressure that forces the water through your slab. During heavy rainfall, excess water can seep into your home's foundation through the concrete slab, leading to various issues that should not be overlooked.
The Repiping Process
Accessing the pipes: Depending on the pipe location, this may involve cutting into walls, ceilings, or the concrete slab itself. Removing old pipes and installing new ones: The plumber will remove the damaged pipes and replace them with new materials, ensuring proper connections and fittings.
Broken Drain Pipe Under Slab
If the broken drain pipe is located under the slab, it can be one of the most expensive pipe repairing projects, costing anywhere between $500 to $4,500 to detect and repair the pipe. The high cost results from the need for the plumber to break through the slab to reach the damaged pipe.