Concrete Patios & Stairs in Kirkland, WA

Patios & stairs in Kirkland: what to know

Kirkland’s drainage review starts when a project adds or replaces at least 500 square feet of impervious surface, or disturbs at least 7,000 square feet of land. A solid concrete patio counts as impervious surface, so the added area is measured before the design is set. Projects that reach the line follow the 2021 King County Surface Water Design Manual with the city’s addendum, which took effect for new projects on July 1, 2022.

Grade matters as much as area. The slab should fall away from the house, roof runoff should go to a dispersal area or drain, and stair treads should not hold water. A raised patio edge that holds back soil is checked against the four-foot line for rockeries and retaining walls, and a critical area on the lot removes the permit exemption.

Permits and rules in Kirkland

Kirkland’s 500-square-foot line still applies to a level patio at grade, because its added area is counted toward it. A rockery or retaining wall over four feet needs a permit, and permit exemptions do not apply in flood hazard, wetland, steep slope, shoreline, or other critical areas. Stair work that reaches the public right-of-way goes through Public Works. We check the added area and wall height against your address before any quote goes out.

Kirkland’s permit guidance requires a permit for rockeries and retaining walls over four feet. Driveway replacement and any work in the public right-of-way need a Public Works permit. Sidewalks 30 inches or less above grade may not need a building permit when they are not over a basement or story below and not part of an accessible route. Permit exemptions do not apply in areas of flood hazard, wetland, steep slope, shoreline, or other land use critical areas. Rules change, so we confirm the current requirements with the city before we start.

How we approach it

Measure the added impervious area against the 500-square-foot line
Set the slab fall toward a lawn, dispersal area, or drain
Measure each raised edge against the four-foot rockery line
Look up the lot’s critical area status before any raised edge is designed

For the full process, see our Concrete Patios & Stairs page.

Building in the cold months? See our guide to winter concrete pours.

Our patios & stairs work, serving Kirkland

Examples of our work. We build patios & stairs in Kirkland and the cities around it. See all of our work

Questions from Kirkland homeowners

At what patio size does Kirkland’s 500-square-foot threshold start to matter?

Kirkland measures it as 500 square feet of impervious surface, counting both newly added and replaced area. Concrete patios add to that area, as does any other new hard surface on the lot, so the total is tallied before the design is locked.

Does a raised Kirkland patio edge need the four-foot rockery permit?

It can. A rockery or retaining wall over four feet needs a permit, and permit exemptions do not apply in critical areas. A patio at grade on a flat lot is the simplest case, so we measure each raised edge before the forms go in.

What does a critical area mean for steps on a steep Kirkland lot?

Permit exemptions do not apply in critical areas, including steep slope areas, so a steep lot can bring the stairs into review. We check the site class, the footing, and the runoff before the design is set.