If you have a plumbing problem underneath your foundation, a tunnel repair is often the way to fix it without tearing up your floors. We dig from outside the house, work under the slab, and put everything back. Here is what actually happens, step by step, so there are no surprises.
Step 1: Find the leak properly
We locate the leak before anyone picks up a shovel, and we locate it precisely. Guessing is expensive here. The point of pinpointing it first is that it decides where the tunnel starts and how long it has to be.
Step 2: Excavate the tunnel
We open a tunnel from the exterior of the house through to the affected area. Every bit of your interior flooring stays where it is. That is the whole reason to choose a tunnel over breaking the slab from inside.
Step 3: Repair or replace the pipe
Once the damaged pipe is exposed we remove it and replace it with code-compliant material, then test the repair before anything gets covered back up.
The new line is hung, not laid. This is the part that decides whether a tunnel repair lasts. Backfill settles no matter how well it is compacted, and a pipe resting on that soil settles with it, loses its fall, and eventually pulls a joint apart. We hang the line from the underside of the slab on threaded rod and strapping, so it holds the grade we set it at regardless of what the dirt underneath does. Every solvent-weld joint gets primer, which is the only way an inspector can tell from the outside that the joint was made correctly.
Step 4: Two inspections, not one
Every tunnel job carries two mandatory inspections, and this is the part homeowners are most often surprised by:
- A city plumbing inspection, confirming the repair meets local code.
- A structural engineer report, verifying the tunnel work has not compromised your foundation.
We coordinate both, so scheduling and approvals are not your problem.
Step 5: Backfill
After the inspections pass, we backfill the tunnel and compact the soil as it goes back in. Compaction is what stops settlement later, so it’s not a step to rush.
Step 6: Clean up
We fill and seal the tunnel, clear the debris, and leave the property clean.
How long does it take, and what does it cost?
It depends on the depth of the slab, the soil, the length of the tunnel and what we find when the pipe is exposed. We’d rather find it, then price it.
Talk to us
We have completed tunnel repairs across San Antonio, Bulverde, Boerne, New Braunfels and the Hill Country, and we handle the whole thing: detection, excavation, repair, both inspections and cleanup.
Call 830-837-2810 and a person answers, or send us the details and we’ll come out and look.