For structural & geotechnical engineers
Engineer-Access Tunnels for Under-Slab Evaluations
An engineer can't certify what they can't see. When an under-slab evaluation needs eyes on a grade beam, a suspected void, a moisture source, or a plumbing penetration, we dig the access to your specification — clean, shored, and safe to enter.
Engineers don't always hire the digger directly, but the dig still has to be done right — and done to OSHA practice — before anyone goes underneath. We work to the engineer's drawing or field direction: where to enter, how far to reach, what to expose. Because we run foundation repair crews ourselves, we speak the language — grade beams, bearing soil, settlement versus heave, differential movement — and we document what we open.
When you call us
The jobs that need a tunnel.
Observe a grade beam or footing
The evaluation hinges on the condition of a beam you can't see from above. We expose it cleanly so it can be measured, photographed, and assessed.
Confirm or rule out a void
Suspected separation between slab and soil needs to be verified, not guessed. We open access to the area in question.
Trace a moisture or soil problem
Wet clay, a leak, or a bearing-soil concern under the slab needs a look. We dig the access so the source can be identified.
Inspect a plumbing penetration
Where a line passes through or under the foundation, the engineer needs to see the detail. We expose it without disturbing the line.
Pre-repair scope verification
Before a repair plan is finalized, an engineer wants to confirm conditions firsthand. Access first, plan second.
What you get
How we work with you.
We treat an engineer's access dig as a precision job, not a hole. The entry point, the reach, and what gets exposed come from your direction; the bore is shored and inspected by a competent person before anyone enters; and we photograph and document the opening so it's part of the record. When the evaluation is done, we backfill and compact, or we leave it open and protected if the repair is following immediately. Many of our engineer relationships turn into referrals — they trust the access work, so they trust us to dig the repair too.
SCOPE OF WORK
- Access dug to the engineer's entry, reach, and exposure spec
- Shored, OSHA-compliant bore safe to enter and observe in
- Grade beams, voids, penetrations, or soil exposed cleanly
- Photo documentation of opened conditions
- Backfill and compaction, or protected open access for an immediate 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 a plumbing or foundation job. We staff the bore to the schedule, dig in clean shifts, and hand the plumber an open, ready trench so their billable hours aren't spent waiting on a shovel.
Precision
We dig to the plan — depth, width, and pitch shot before the first spade, then verified as we go. The pipe run, the pier location, or the engineer's access point lands where the drawing says it should, the first time.
OSHA safety
Tunneling and trenching carry real cave-in exposure. 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: width to work in, clean floor and walls, true pitch, and a documented hand-off. Backfill is placed and compacted in lifts so the ground — and anything on it — settles right.
Standards & compliance
Texas 811 is called and lines are located before we dig. We sell the access, not the licensed pipe work — your plumber stays the plumber. 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 under a slab actually runs, where the belly usually hides, and how much room a plumber needs to set a fitting, swing a saw, and lie comfortably to make a joint. We open the work area wider where the repair is, shore it, keep it dry, and light it — then get out of the way. The plumber shows up to a tunnel they can work in, not a hole they have to fight. That's the difference between a bore dug by people who've only moved dirt and one dug by a foundation crew who has watched the pipe work happen a hundred times.
- We open the work area wider where the repair is — 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 to your licensed plumber, foundation crew, or engineer — open, dry, and workable.
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 — Tradesman, Journeyman, Master, and Inspector licenses. Motmot sells under-slab tunneling and access excavation; we partner with your licensed plumber for the pipe repair itself. And before any dig, Texas 811 is contacted at least two business days ahead so gas, water, and utility lines are located first.
Industry FAQ
Structural engineers 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 →Foundation repair
Foundation repair tunneling.
See foundation repair 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.