Concrete Tear-Out and Replacement

Common scope

Locate utilities, saw-cut, break out, haul, fix base, form, pour, joint, cure

Before digging

Kansas 811 notice at least two full working days ahead

Hidden issues

Soft base, voids, roots, old buried slabs

Right-of-way

Wichita approach and sidewalk work needs a City permit

Is it time to replace?

Replacement usually wins over repair when several of these are true:

• Panels have shifted in different directions, creating trip edges or ponding.
• Cracks run through many panels and keep widening.
• Scaling has worn through to the coarse aggregate across large areas. NRMCA describes severe scaling as surface loss that leaves the aggregate clearly exposed and notes that repairing slabs with excessive, progressing scaling may not be feasible (NRMCA, CIP 2: Scaling Concrete Surfaces).
• Patches fail every winter.
• The slab slopes toward the house or garage and sends water where it should not go.
• The layout no longer fits: too narrow, too short, or in the wrong place.

If only one or two panels are bad, partial replacement along existing joints is common. See repair and resurfacing and lifting and leveling for alternatives.

Call 811 first

Breaking out concrete and regrading is excavation. Kansas statute K.S.A. 66-1804 requires an excavator to give notice of intent to excavate at least two full working days, and not more than 20 calendar days, before the scheduled start (K.S.A. 66-1804, notice of intent of excavation). Kansas 811's waiting-period table shows how the days count, with weekends and listed holidays excluded (Kansas 811, waiting period table). Locates mark public utility lines; private lines such as sprinkler pipes, landscape lighting and invisible fences are not marked by the utility locate, so tell the estimator where they run. Read the 811 guide for details.

How removal works

1. Saw-cut the edges. A clean saw cut where old concrete stays, such as at the approach, a sidewalk or the garage floor, keeps the break from running into concrete you want to keep.
2. Break it up. Jackhammers, breakers on skid steers or other equipment reduce the slab to pieces. Reinforcement is cut free.
3. Haul it away. Broken concrete is heavy. It is loaded and hauled, often for recycling as aggregate.
4. Inspect the base. With the slab gone, soft spots, voids, roots and drainage problems become visible.

The base is the real job

The concrete failed for a reason, and the reason is often still in the ground. NRMCA lists improper subgrade preparation among the main causes of cracking and calls for removing topsoil and soft spots and compacting the soil or granular fill under a new slab (NRMCA, CIP 4: Cracking Concrete Surfaces). On Wichita-area clay, the Kansas Geological Survey and K-State both describe soil that heaves when wet and shrinks when dry (Kansas Geological Survey, GeoRecord: geologic hazards and expansive soils; K-State Research and Extension, Clay Soil: It Shrinks and Swells). Replacing soft or organic material, compacting in layers and correcting slopes so water drains away are what keep the new slab from repeating the old one's story.

Protecting what stays

• The approach and public sidewalk: in Wichita, anything in the right-of-way is replaced to City specifications under a City permit (City of Wichita, Traffic, Street and Construction Permitting).
• Lawn and landscaping: equipment paths, mats and cleanup plans.
• The garage floor and foundation: clean cuts and isolation joints where new concrete meets old.
• Trees: roots near the slab may be cut during removal; ask before roots of a tree you value are cut.

Pouring the replacement

The new slab should follow the same freeze-thaw basics as any outdoor concrete around Wichita: air-entrained concrete with a specified strength suited to exposure, which NRMCA puts at 4,000 psi for slabs that stay wet, freeze and see de-icers (NRMCA, CIP 2: Scaling Concrete Surfaces); joints laid out at sensible spacing with isolation joints at the house, walks and curbs (NRMCA, CIP 6: Joints in Concrete Slabs on Grade); and proper curing (NRMCA, CIP 11: Curing In-Place Concrete). The driveway page explains each of these in more detail: concrete driveways.

Timing and access

A driveway tear-out leaves the garage unusable for a stretch, including the cure time before cars can return. Plan parking, trash pickup and deliveries. Spring and fall, between the average last freeze around April 9 and first freeze around October 25 per NWS Wichita (NWS Wichita, annual climate normals for Wichita, Salina and Chanute), are the easiest seasons for removal and replacement.

The estimate factors page lists what changes the size of a removal job: area, thickness, reinforcement, access and base repair.

Sizing up the job: see what changes the size of a removal job on the estimate-factors page. It lists what moves the scope, never a price.

Further reading

• Expansive Clay Soil and the Slabs That Sit on It
• City of Wichita Sidewalk and Drive Approach Rules
• Cracks, Joints and Heaving in Wichita Concrete
• Call 811 Before Tearing Out or Digging for Concrete
• Reading a Concrete Estimate or Contract in Kansas