When a drain under a bathroom fails, there are two ways to reach it: break through the floor from inside, or tunnel under the slab from outside. On this job, we tunneled.
What we did
The drain under a bathroom had failed. Instead of jackhammering through the finished floor, we dug in from outside and tunneled under the slab to reach it. We replaced the trap and line with new PVC, and hung it on threaded rod and hangers so it holds the correct slope while the tunnel is backfilled.
When tunneling makes sense
- The floor above is tile, stone, or hardwood that would be expensive to replace
- The home is occupied and the family needs the bathroom back quickly
- The problem is close enough to an outside wall to reach
When going through the floor makes sense
- The problem is in the middle of the house, far from any outside wall
- The floor is already being replaced
- The repair is small and a tunnel would be longer than it's worth
What to ask for
If you're facing an under-slab repair, ask for both prices: through the floor and tunneling. Then compare the plumbing cost plus the cost of putting your floors back.
