For foundation repair · What we do daily
Foundation Repair Tunneling & Interior Pier Access
Sometimes the piers a house needs sit in the middle of the slab, not at the perimeter. Breaking a finished floor to reach them is the most disruptive way in. We tunnel under the slab instead, so interior piers go in from below and the floors above stay whole.
This is the work Motmot knows from the inside out, because we run our own foundation repair crews. When the elevation survey calls for interior support, the pier locations come off a plan and the bore has to reach every one of them at pier depth. We dig to those marks, keep the under-slab plumbing protected while the house comes back toward plane, and backfill once the piers are set and capped.
When you call us
The jobs that need a tunnel.
Interior piers required by the survey
The floor sinks toward the center. Interior piers are the fix, and tunneling reaches them from below without sawing through tile and the rooms above.
Plumbing must be protected during the lift
When a house is leveled, the rigid drain lines under it are stressed. Tunneling lets the plumbing be located, protected, or repaired as part of the same dig.
No exterior access to the work area
Tight lot lines, additions, or hardscape block the spot that needs support. A tunnel reaches it from a workable entry point instead.
Keeping the home livable
Tunneling from outside, or from one interior entry, keeps most of the house usable while the structural work happens underneath.
What you get
How we work with you.
Because the crew tunneling for the piers and the crew setting the piers come from the same shop, the access lands where the pier plan needs it, at the right depth, with room to drive and cap. We have dug enough of these to protect what is already down there. We know where the sewer and supply lines run under a typical Central Texas slab and we keep them safe while the structure moves. When the piers are in, backfill goes in compacted lifts so the repair stays put. If someone else is quoting your tunnel, ask them where the pier depth came from. If the answer is not the elevation survey and the pier plan, the depth is a guess and you will find out at the bottom of the hole.
SCOPE OF WORK
- Tunnels dug to the marked interior pier locations, at pier depth
- Under-slab plumbing located and protected during the lift
- Engineer-access openings dug to spec where required
- Backfill and compaction in lifts once piers are set and capped
- Coordinated with the same crew that performs the repair
How every bore is held
Velocity, precision, OSHA, quality control, and the standards behind them.
Tunneling is the slow, risky part of a plumbing or foundation job. We run it like a discipline, not a dig.
Velocity
Hand-tunneling is the slow part of any plumbing or foundation job. We staff the bore to the schedule and hand over an open, ready trench instead of billable hours spent waiting on a shovel.
Precision
We dig to the plan. Depth, width and pitch are shot before the first spade and verified as we go, so the pipe run or the pier lands where the drawing says.
OSHA safety
Cave-in exposure is real. We work to OSHA Subpart P excavation practice: protective systems, safe access and egress, spoil set back from the edge, water and air managed, and daily competent-person inspection.
Quality control
Every bore is checked against the drawing for working width, clean floor and walls, and true pitch. Backfill goes in compacted lifts so the ground above settles right.
Standards & compliance
Texas 811 is called and lines are located before we dig. We sell the access, not the licensed pipe work. Permits, locates and clean documentation come standard.
Why a foundation crew digs a better tunnel
We come out of foundation repair, and we've dug alongside plumbers for years, so we know how to dig it.
We know how a sewer line runs under a slab, where the belly usually hides, and how much room it takes to set a fitting and lie down to make a joint. So we open the bore wider at the repair, shore it, keep it dry, light it, and get out of the way. Years of watching the pipe work happen is what tells us how wide to make it.
- We open the work area wider where the repair is, leaving room to set, slope, and joint
- Shored, dry, and lit so the plumber works in a tunnel, not a hole
- We dig it and back-fill it; your licensed plumber does the pipe work
From locate to backfill
How an under-slab tunnel runs.
Locate & plan
We call Texas 811, locate utilities, and shoot the depth, width, and pitch the repair needs before a spade hits the ground.
Open the entry
A compact entry pit goes in at the chosen point, usually outside the foundation, so the floors above stay whole.
Tunnel to the work
We hand-tunnel to the pipe run, pier location, or access point, widening the bore where the repair happens.
Shore & hand off
The bore is shored and inspected, then handed off open, dry, and workable to your licensed plumber, foundation crew, or engineer.
Backfill in lifts
Once the repair passes, we place backfill in compacted lifts so the slab, drive, or walk above settles correctly.
Clean & document
Spoil hauled, site restored, and the access and backfill documented for your file or warranty.
LICENSING & SAFE DIGGING
In Texas, plumbing repairs are regulated by the Texas State Board of Plumbing Examiners, which issues Tradesman, Journeyman, Master, and Inspector licenses. Motmot sells under-slab tunneling and access excavation, and partners with your licensed plumber for the pipe repair. Before any dig, Texas 811 is contacted at least two business days ahead so gas, water, and utility lines are located first.
Industry FAQ
Foundation repair tunneling, questions answered.
From real jobs
What this access looks like on real jobs.
Tunneling for other industries
Plumbing companies
Under-slab tunneling for plumbers.
See plumbing companies tunneling →Structural engineers
Engineer-access excavation for under-slab evaluations.
See structural engineers tunneling →GCs & remodelers
Under-slab access for remodel plumbing.
See gcs & remodelers tunneling →Property mgmt & multifamily
Low-disruption under-slab tunnel access for rental and multifamily properties.
See property mgmt & multifamily tunneling →Investors & flippers
Pre-sale and investor property tunneling for plumbing/foundation access.
See investors & flippers tunneling →Realtors & inspectors
Under-slab access for repair work before closing.
See realtors & inspectors tunneling →Restoration & insurance
Access excavation for slab leak and water-damage repairs.
See restoration & insurance tunneling →Commercial facilities
Commercial under-slab tunneling for plumbing and structural access.
See commercial facilities tunneling →Backfill & cleanup
Tunnel backfill and cleanup.
See backfill & cleanup tunneling →Need under-slab access? Tell us the run.
We'll scope the tunnel, dig it to plan, shore it, and back-fill it clean, so your licensed repair goes in smoothly and the floors above stay whole.
Now booking free inspections in Central Texas.