South King County
Paver Patios in Kent, WA
Quick answer
A paver patio in Kent is a base problem before it is a paver problem. On East Hill, winter rain perches on Alderwood hardpan and travels sideways under the field, so an intercept drain goes into the section. Down on the valley floor the shallow water table sets base depth. Our shop is ten minutes away.
Most of the patios we get called out to replace on Kent's East Hill were built to the wrong standard for the ground underneath them. Three inches of pit run. Mason sand instead of angular chip. No thought given to where water goes once it reaches the hardpan a foot or two down. Alderwood till doesn't accept water. It holds it. So the patio on top becomes a low dam, collecting everything the lawn above it sheds. By the third winter you've got a soft corner and moss in the joints. A rebuild means excavating to native, laying woven separation fabric, and running a perforated intercept drain in washed rock along the uphill edge of the rock section. Then the base can shed water instead of storing it.
Riverview, North Park and the streets off Central Avenue flip that around. That's Green River alluvium at roughly thirty feet of elevation. Silt loam with a February water table only a few feet down. Work it wet under a plate compactor and it pumps into soup. So we over-excavate. Somebody walks the exposed subgrade behind the machine looking for anything that rebounds. Then we build a deeper compacted section. Finished grade often ends up an inch or two proud of the surrounding lawn. That's on purpose, so water leaves the patio for the turf instead of running the other way.
Paver and base stock comes off the rack at Mutual Materials and Basalite. Both are a short run from the shop off 116th, so a job gets closed in between weather windows. Our own crew sets the stone, so the base depth written on the estimate is the base depth that actually gets buried.
What’s different about Kent
Kent is two cities at different elevations, and a patio gets designed for whichever one you live on. East Hill needs a drain path for water perched on hardpan. The valley floor needs a deeper, proofed section, because the subgrade down there is soft and shallow to groundwater.
Paver Patios cost in Kent
| Item | Typical range | Unit |
|---|---|---|
| Standard concrete paver patio, running bond or herringbone | $22-$30 | per sq ft |
| Premium or large-format paver patioTecho-Bloc and Belgard slab lines, tighter tolerances and more cutting. | $30-$45 | per sq ft |
| Dry-set natural flagstone patio | $38-$60 | per sq ft |
| Over-excavation and structural fill on a soft subgradeDigging, haul-off, and imported rock combined. | $60-$95 | per cubic yard |
| Paver seat wall integrated into the patio edge | $65-$110 | per linear ft |
| Channel drain with piped outfall to daylight | $45-$85 | per linear ft |
These are typical installed ranges for the Puget Sound market and include labor, base, and materials; the number that ends up on your proposal comes from a site walkthrough where we can see access, grade, and what the subgrade is actually made of. Bids around $15 a square foot exist here and they are usually the same pavers over four inches of base instead of eight to twelve, laid on fabric-free subgrade. On Alderwood till that is the difference between a flat patio and a wavy one by the third winter.
Permits in Kent
Work inside the city goes through the City of Kent Permit Center downtown on West Gowe Street. A retaining wall over 4 feet, measured from the bottom of the footing to the top of the wall, needs a permit and stamped structural engineering. In practice that threshold drops as soon as the wall picks up a surcharge from a driveway, a slope, or a structure above it. Kent also runs its own surface water design manual, adapted from King County's. Add impervious surface past the review threshold and a patio or driveway can land in drainage review even when the hardscape itself is exempt. Grading volume triggers its own review. So does work in a mapped erosion or landslide hazard area, or anything near the Green River levees or a stream buffer like Mill Creek or Garrison Creek. Fences 6 feet and under in a side or rear yard generally don't need a permit, though corner and driveway sight-distance rules still apply. Thresholds get revised. We confirm scope with the city at permit time instead of guessing from the last job.
Paver Patios in Kent: questions
Why does one corner of my East Hill patio sink every winter?
Almost always the base. Almost always water. The till under East Hill carries a cemented hardpan twelve to thirty inches down, and it behaves like the floor of a bathtub. Rain soaks the shallow soil, perches on that layer, then moves sideways into your rock section. Base rock that stays saturated loses its interlock. The corner nearest the uphill grade is where it shows up first. The fix is an intercept drain along the uphill edge and a rebuilt section on separation fabric. Another pass of polymeric sand won't do anything for you.
Can you build a paver patio on the Kent valley floor?
Yes, we do it around Riverview and North Park regularly. What changes is the section underneath. Alluvial silt with a shallow winter water table will pump under a compactor if it gets worked wet. So we over-excavate, proof the subgrade, and build a deeper compacted rock section over woven geotextile. Scheduling matters more down there than up the hill. A dry stretch in late summer buys you a better base than the same crew can build in February.
Do I need a permit for a paver patio in Kent?
An at-grade patio generally doesn't need a building permit. Two things can still pull one into review. First, total new plus replaced hard surface crossing the drainage threshold in the surface water design manual Kent has adopted, which starts near 2,000 square feet. Second, any work inside a mapped critical area, wetland buffer or steep slope. Raising a patio high enough that it reads as a deck changes the answer too. We confirm current thresholds with the city before a layout is final.
What does a paver patio cost in Kent?
In the Puget Sound market in 2026, a standard concrete paver field runs roughly $22 to $30 per square foot installed. Large-format or premium units run $30 to $45. Those are market ranges for planning, not a quote. In Kent two items move a number most. One is over-excavation on a soft valley subgrade, commonly $60 to $95 per cubic yard for dig, haul-off and imported rock combined. The other is getting a drain line to a legal outlet on a flat lot.