How Thick Should a Concrete Driveway Be in Spokane? 4, 5 or 6 Inches, Rebar, Base and Approach Rules (2026)

Short answer: for cars and pickups, a well-built concrete driveway in Spokane is 4 inches thick at minimum, and 5 to 6 inches is the better choice if delivery trucks, a loaded pickup and trailer, an RV or a boat will use it. Where your driveway meets a City of Spokane street, the approach has to be 6 inches of air-entrained concrete over 4 inches of compacted crushed rock. Thickness is only half of it, though. In a freeze-thaw climate like ours, the mix, the base and the joint spacing decide whether a driveway lasts. Here's what the codes and concrete industry guides say, and how we build driveways around Spokane.

How thick should a driveway be?

Concrete industry driveway guides line up on these minimums:

• Passenger cars and pickups: 4 inches is the standard minimum (Virginia Ready Mixed Concrete Association, Michigan Concrete Association)
• Delivery vehicles or light trucks: 5 inches minimum per the Michigan Concrete Association; Virginia's guide says 5 to 6 inches for light trucks
• RVs, larger trucks and trailers: 5 inches or more per Concrete Manitoba, and thicker still for heavy trucks
• Code floor: the residential concrete code, ACI 332-20, sets an absolute minimum of 3-1/2 inches for slabs, which is why you should treat 4 inches as the real starting point

Keep the thickness uniform. A slab that's 4 inches in the middle and 3 at the edges cracks at the thin spots, which is why the base has to be graded flat before anything is poured.

Spokane-area approach rules

The part of the driveway in the public right-of-way has its own standards:

• City of Spokane: Standard Plans F-103 through F-104B require a 6-inch minimum of air-entrained, 6-sack commercial concrete over 4 inches of compacted crushed surfacing top course (CSTC) in the approach. A thickened edge is required where the driveway doesn't butt up to existing pavement, and tooled contraction joints in the approach are 1/4 inch wide by 2 inches deep
• City permits: you need a driveway approach permit, review takes up to 5 working days, and a contractor licensed to work in the right-of-way then pulls a separate street obstruction permit
• Width limit (City): approaches can take up to 40% of your street frontage, to a maximum of 30 feet
• Spokane County, urban roads: approach concrete is 6-sack commercial, air-entrained per the County's "Cement Concrete Approaches" standard plan, with full-depth expansion joints down the center of driveways over 20 feet wide
• Spokane County, rural roads: the County won't let concrete run to the road edge. Keep concrete back 5 feet and tie into the road with asphalt or gravel; 5/8-minus crushed rock is the largest allowed in the right-of-way

If you're in Spokane Valley, Liberty Lake or another city, the approach follows that city's standard plans, and we check them before we form anything.

The mix matters as much as the thickness

Spokane driveways see snow, meltwater, freeze-thaw cycles and deicers tracked in on tires. The building codes and concrete code treat that as severe exposure:

• ACI 332-20 (residential concrete code): for flatwork exposed to freeze-thaw and deicing chemicals, like driveways, curbs, steps and porches, it calls for 4,500 psi concrete with a maximum water-to-cement ratio of 0.45, air-entrained at about 6% for 3/4-inch to 1-inch rock. The 2014 edition only required 4,000 psi
• International Residential Code, Table R402.2: in the severe weathering region, garage floors, porches and carport slabs need at least 3,500 psi with 5 to 7% entrained air

Air entrainment puts billions of tiny bubbles in the concrete that give freezing water somewhere to go. Without it, the surface scales and pops in a few winters. Adding water on site to make the mix easier to place weakens it, so we don't.

Base: what goes under the slab

• Remove soft soil: the Michigan Concrete Association's guideline says to dig out unstable material at least 6 inches deep and replace it with compacted crushed stone, gravel or sand
• Sub-base: at least 4 inches of compacted granular base, matching the 4 inches of CSTC the City of Spokane requires under approaches
• Never on frozen ground: concrete shouldn't be placed on frozen subgrade, which is one reason winter driveway pours need extra planning. See our guide to pouring concrete in winter
• Drainage: slope the driveway away from the garage and house so meltwater doesn't pond and refreeze

Joints: where the cracks are allowed to happen

Concrete shrinks as it cures and moves with temperature, so it will crack. Control joints decide where:

• Spacing by thickness: about 10 feet apart for a 4-inch slab, 12.5 feet for 5 inches and 15 feet for 6 inches (Pennsylvania Aggregates and Concrete Association)
• Depth: at least 1/4 of the slab thickness, so 1 inch in a 4-inch driveway
• Panel shape: as square as possible, never longer than 1.5 times the width. Driveways 12 feet or wider get a joint down the center
• Timing: saw cuts go in as soon as the concrete can take the blade without raveling, and within 24 hours at the latest per the Michigan Concrete Association
• Isolation joints: full-depth joints where the driveway meets the garage slab, sidewalk, curb or street

Our driveway cracking guide covers which cracks are normal and which are a warning sign.

Do you need rebar or wire mesh?

Reinforcement doesn't stop a driveway from cracking. Concrete Manitoba's driveway guide notes that rebar, mesh or fibers aren't required, but they hold cracks tight and can allow wider joint spacing. Rebar earns its keep where the soil is questionable, where heavy vehicles will park, or where the driveway transitions onto a thicker approach. Smooth dowels across joints that traffic crosses keep neighboring panels level. We'll tell you on site whether your driveway needs it.

Our recommendation

• Typical Spokane home, cars and pickups: 4 inches minimum, and many owners choose 5 for the extra margin
• Trucks, trailers, RVs or a boat: 5 to 6 inches, thicker where the heavy wheels sit, with reinforcement
• Approach onto a City street: 6 inches, built to the City's standard plan with the right permits
• Every driveway: air-entrained mix, compacted base, slope for drainage and joints cut on time

Thinking about whether to fix or replace an old driveway first? Read our repair vs. replacement guide, and our sealing guide for the first winter.

Get a driveway quote

Every driveway is priced on its size, thickness, base work, tear-out and approach requirements, so we quote each one after a site visit. Call 509-350-2016 or request a free quote, and see our concrete flatwork services.

Sources

• City of Spokane Standard Plans, Section F (driveway approaches F-103 to F-104B)
• City of Spokane Driveway Approach Application
• Spokane Municipal Code 17H.010.220, Driveways
• Spokane County Urban Residential Approaches packet
• Spokane County Rural Residential Approaches packet
• ACI 332-20, Code Requirements for Residential Concrete (preview)
• Tennessee Concrete Association, ACI 332-20 highlights for driveways
• Carolinas Ready Mixed Concrete Association, deicer scaling resistance and ACI 332-20
• IRC Table R402.2 concrete strength summary
• Virginia Ready Mixed Concrete Association, Concrete Essentials
• Michigan Concrete Association, Driveway and Sidewalk Guidelines
• Concrete Manitoba, Driveways and Garage Slabs
• Pennsylvania Aggregates and Concrete Association, Cracking in Concrete