Concrete driveway installation, thickness is not the whole answer

What is driveway installation?

A concrete driveway is a reinforced slab poured over a compacted aggregate base, jointed so shrinkage cracking follows planned lines, and graded so water runs off it and away from the house. It typically takes a few days from excavation to pour, and considerably longer before vehicles are allowed on it. Thickness matters, but a thick slab on a poorly compacted base fails just as reliably as a thin one.

Signs you need driveway installation

• The existing driveway is cracked across multiple panels or has broken up at the apron
• Sections have settled so the surface is uneven or ponds water after rain
• The surface is scaling badly after winters of de-icing salt
• You are widening for a second vehicle, adding a turning area, or adding a parking pad
• Gravel is migrating into the yard and needs topping up every year
• Water runs down the driveway toward the garage or the house rather than away
• A new build or an addition has changed where the driveway needs to be

Seeing something not on this list? Browse concrete problems by symptom →

How driveway installation actually works

1. 1

   Layout, levels and drainage design

   The driveway is set out with its fall worked out first - where water enters, where it leaves, and how it meets both the street and the garage threshold. Every other decision follows the drainage.

   Watch forWater directed toward the garage or the house. A driveway that slopes back to a threshold puts water at the foundation every time it rains, and correcting it later means removing the driveway.

2. 2

   Excavation and subgrade assessment

   Topsoil and any soft or organic material is dug out down to a stable subgrade. Where the subgrade itself is poor, it gets removed and replaced rather than compacted in place.

   Watch forForms set on topsoil, or a driveway built on ground that was recently filled. Organic material continues to break down and consolidate, and the slab settles into the space it leaves.

3. 3

   Base placement and compaction in lifts

   Crushed aggregate is placed in layers, each compacted with a plate compactor or roller before the next goes on. This is the load-carrying element of the whole assembly.

   Watch forThe whole base dumped in one thick layer and compacted once from the top. Compaction does not reach the bottom of a deep lift, and the un-compacted portion consolidates later under vehicle loads.

4. 4

   Forming, thickness and reinforcement

   Forms are set to line and grade, then rebar or heavy wire mesh is positioned on chairs. Driveways need more thickness and more reinforcement than a walkway, and heavier vehicles need more again.

   Watch forA single thickness quoted regardless of what you park. If a truck, an RV or a trailer will use it, say so before the quote - reinforcing for it afterwards is not possible.

5. 5

   Pour, screed and finish

   Concrete is placed and struck off, floated, then given a broom finish for traction. In freezing climates the mix should be air-entrained, which builds in microscopic voids that accommodate freezing water.

   Watch forWater added to the truck on site to make placement easier. It is the single most common way a driveway is quietly weakened, and it happens where you can see it if you are there.

6. 6

   Jointing

   Control joints are cut in a pattern based on slab thickness, and isolation joints separate the driveway from the garage slab, the street and any fixed structure so they can move independently.

   Watch forThe driveway poured hard against the garage slab or a foundation wall with no isolation joint. The two will move differently and the crack that results goes exactly where you did not want it.

7. 7

   Curing and protection

   The slab is cured to keep moisture in while it gains strength, and protected from traffic. Vehicles wait considerably longer than foot traffic, and heavy vehicles longer again.

   Watch forA contractor who does not give you a specific date for driving on it. Early vehicle loading is one of very few ways a homeowner can permanently damage a correctly poured slab.

8. 8

   Sealing and first-winter care

   In freeze-thaw regions the slab is usually sealed after it has cured, and de-icing salts are best kept off it entirely during its first winter.

   Watch forSealer applied too early. Concrete needs to cure before it is sealed, and sealing a green slab traps moisture in the surface layer you are trying to protect.

What does driveway installation cost?

Concrete driveways are priced per square foot, with thickness, reinforcement, excavation depth, base material and site access driving the range. Removing an existing driveway is a separate line item priced by disposal weight. Decorative finishes add substantially. See the Cost Guide.

See the full driveway installation cost guide - by material, size and region →

If the number is the problem, here are the ways people pay for it →