What a Deck Costs in Kent, WA
Planning ranges by material and size, compiled from what deck builders serving south King County publish, with the reasons a Kent quote lands where it does.
Per Square Foot, Installed
In the Kent area a new deck costs about $30 to $50 per square foot in pressure-treated lumber, $35 to $60 in cedar, $45 to $75 in capped composite, and $50 to $85 in PVC, installed on a flat lot near grade. Height, stairs, railing, and tear-out add to that.
| Decking | Installed, per sq ft | 12 × 16 deck (192 sq ft) | 16 × 20 deck (320 sq ft) |
|---|---|---|---|
| Pressure-treated fir | about $30–$50 | about $5,800–$9,600 | about $9,600–$16,000 |
| Western red cedar | about $35–$60 | about $6,700–$11,500 | about $11,200–$19,200 |
| Capped composite | about $45–$75 | about $8,600–$14,400 | about $14,400–$24,000 |
| PVC | about $50–$85 | about $9,600–$16,300 | about $16,000–$27,200 |
The ranges pull together several published sources: a cost survey that polled Kent deck builders and put cedar at $32 to $37 and composite at $38 to $40 per square foot, a Bellevue exteriors firm's statewide replacement figures of $30 to $45 for cedar and $45 to $65 for composite, and a Puget Sound fence-and-deck company's Seattle figures of $30 to $45 for cedar and $28 to $45 for composite. Two Seattle-city deck builders publish figures roughly double these, $60 to $90 for cedar and $75 to $130 for composite, which reflects the city's labor and permit costs and the larger, more engineered decks they build. South King County quotes tend to land near the lower set, and a builder who quotes Kent at Seattle rates should be able to say what the extra buys.
What Moves a Kent Quote
Height and the lot
A deck off the upper floor of an East Hill split-level needs eight-foot posts, a heavier beam, diagonal bracing, and a stair flight with a landing, and its footings go into till that needs a real excavator rather than a post-hole digger. A Mercer Island builder puts the sloped-lot premium at $8,000 to $20,000 over a flat-lot build, with engineered footings alone at $2,000 to $6,000. Kent's hills are gentler than that, but a two-story deck still costs half again what the same footprint costs at grade.
Stairs and railing
A flight of stairs runs about $1,500 to $4,000 depending on rise and whether it has a landing. Railing is priced per linear foot: basic wood at about $50 to $100, aluminum in between, and cable or glass at $100 to $250. On a 12-by-16 deck with three open sides that is 40 feet of rail, so the railing choice alone can swing the total by $6,000.
Tear-out
Removing an old deck and hauling it runs about $5 to $15 per square foot, and finding a rotted rim joist behind the old ledger adds a wall repair before the new ledger goes on. See deck replacement.
Permit and inspections
Kent's building permit fee is set from the project's valuation on the city's fee table, and Seattle-area builders budget 5 to 15 percent of the job for permits and inspections, which on a Kent deck usually means several hundred dollars to around $2,000. Drawings, if the builder does not produce them in-house, are extra.
A roof
About $20 to $60 per square foot for an aluminum or basic framed cover and $60 to $120 for a shingled wood roof. Details on the covered decks page.
Cedar and Composite Over Twenty Years
The upfront gap between cedar and composite on a 192-square-foot deck is roughly $2,000 to $3,000. Cedar then needs cleaning and resealing every two years or so; at a few hundred dollars in materials and a weekend each time, or $500 to $1,000 hired, that is $2,500 to $10,000 over twenty years, and at the end of it the cedar deck is at or past its expected 15-to-25-year life while the composite is at the middle of its 20-to-30. That arithmetic is why composite has become the default on Kent replacements. Cedar still wins on first cost, on looks, and for owners who like the ritual.
Reading Two Quotes
- Same material, same spec. A "composite" line without a product name and a "cedar" line without a grade are not comparable. Ask for the board, the joist spacing, and the fastener type.
- The frame details. Joist tape, standoff post bases, ledger flashing, and hold-downs should be listed. A quote that is $1,500 cheaper and does not mention them is usually $1,500 cheaper for that reason.
- Permit, drawings, and inspections as a line item, with who pulls it.
- Tear-out and disposal priced separately, with what happens if the wall behind the ledger needs work.
- The contractor's L&I registration number, which can be checked on the state's site in a minute.