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, and no thought given to where water goes once it reaches the hardpan a foot or two down. Alderwood till does not accept water. It holds it. A patio set on top of that becomes a low dam collecting everything the lawn above it sheds, and by the third winter there is 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 so the base can shed instead of store.
Riverview, North Park and the streets off Central Avenue invert the problem. That is Green River alluvium at roughly thirty feet of elevation, silt loam with a February water table only a few feet down, and it will pump into soup under a plate compactor if you force it while it is wet. We over-excavate, walk the exposed subgrade behind the machine looking for anything that rebounds, and build a deeper compacted section. Finished grade often ends up an inch or two proud of the surrounding lawn on purpose, so the patio drains to the turf rather than the turf draining onto the patio.
Paver and base stock comes off the rack at Mutual Materials and Basalite, both a short run from the shop off 116th, which keeps a job closed in between weather windows. We draw the layout in our own office and 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 itself 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.
Permits in Kent
Work inside the city goes through the City of Kent Permit Center downtown on West Gowe Street. Retaining walls over 4 feet measured from the bottom of the footing to the top of the wall need a permit and stamped structural engineering, and that threshold drops in practice as soon as a 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, so adding impervious surface past the review threshold can pull a patio or driveway into drainage review even when the hardscape itself is exempt. Grading volume, work in a mapped erosion or landslide hazard area, and anything near the Green River levees or a stream buffer such as Mill Creek or Garrison Creek all trigger their own review. Fences 6 feet and under in a side or rear yard generally do not need a permit, subject to corner and driveway sight-distance rules. Thresholds get revised, so we confirm scope with the city at permit time rather than 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, and almost always water. The till under East Hill carries a cemented hardpan twelve to thirty inches down that behaves like the floor of a bathtub. Rain saturates the shallow soil, perches on that layer and moves laterally into the rock section. Base rock that stays saturated loses its interlock, and the corner nearest the uphill grade is where it shows first. The correction is an intercept drain along the uphill edge and a rebuilt section on separation fabric, not another pass of polymeric sand.
Can you build a paver patio on the Kent valley floor?
Yes, and we do it around Riverview and North Park regularly. The section changes rather than the design. Alluvial silt with a shallow winter water table will pump under a compactor if it is 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 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 does not require a building permit. Two things can still pull one into review: 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, and 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 as well. We confirm current thresholds with the city before a layout is final.
What does a paver patio cost in Kent?
Typical installed ranges for the Puget Sound market in 2026 run roughly $22 to $30 per square foot for a standard concrete paver field and $30 to $45 for large-format or premium units. Those are market ranges for planning, not a quote. In Kent the two items that move a number most are over-excavation on a soft valley subgrade, commonly $60 to $95 per cubic yard for dig, haul-off and imported rock combined, and getting a drain line to a legal outlet on a flat lot.