Concrete removal and replacement

Usually fine to leave or repair

• Hairline cracks that are level on both sides. Nearly all concrete gets them. Sealing them keeps water out and slows any widening.
• One slab that has sunk but is still in one piece. Slab lifting pumps material underneath to raise it back to level, for a fraction of the price of replacement.
• A single damaged panel in an otherwise sound driveway or walk. It can be cut out at the joints and replaced on its own. The new panel will be a lighter color for a few years.

Usually time to replace

• The surface is flaking or pitting over a wide area. This is called scaling or spalling, and it means the top layer could not take freeze-thaw and salt. Resurfacing products are sold for it, but in Michigan they often peel within a few winters.
• Cracks are wide, or one side sits higher than the other. The ground underneath has moved and will keep moving.
• Water runs toward the house or garage because the slab has settled the wrong way. This one matters most, since the damage it causes is to your foundation.
• The slab is broken into many pieces, or tree roots have lifted it.

What removal involves

1. Utilities are marked. Michigan law requires a call to MISS DIG 811 at least three business days before digging. The contractor normally handles it.
2. The old concrete is broken up and hauled away. Much of it is recycled into crushed concrete for road base.
3. The base is corrected. This is the step that decides whether the new slab lasts. Soft soil comes out, gravel goes in, and it is compacted. Pouring new concrete on the base that failed the old slab buys you the same problem again.
4. The new slab is formed and poured, usually a day or two after the tear-out.

What it costs

Breaking out and hauling away old concrete typically adds $2 to $5 per square foot to the price of the new pour. A full replacement of an 800 square foot driveway therefore comes to about $8,000 to $15,200. Thick slabs, slabs with rebar in them and back yards with no access for equipment sit at the high end.

Common questions

Can I break it out myself to save money?

You can, and some contractors will price the pour alone. Be realistic about it: a two-car driveway is 15 to 20 tons of broken concrete to load and dump, and the contractor will still want to inspect and fix the base.

Why did my driveway flake when the neighbor's did not?

The usual causes are a mix without enough air entrainment, too much water added on pour day, finishing while water was still on the surface, or deicing salt in the first winter. Read how to care for new concrete before your replacement goes in.