How Much Does a New Deck Cost? Pricing by Size and Material
The backyard needs a deck. The budget is somewhere between "reasonable" and "let's not talk about it." The first quote arrives, and it's higher than expected. The second quote is lower but doesn't include railing. The third quote includes everything, but the number makes the kitchen renovation look cheap. Nobody's wrong—they're pricing different sizes, materials, and finishes.
Deck costs in Portland vary widely because the variables stack up. A ground-level 12x16 platform made of pressure-treated wood is fundamentally different from a second-story wraparound composite deck with built-in benches. Here's how the pricing actually breaks down.
Cost by Material
| Material | Cost Per Sq Ft (installed) | 200 Sq Ft Deck | 300 Sq Ft Deck | 400 Sq Ft Deck |
|---|---|---|---|---|
| Pressure-treated wood | $15-25 | $3,000-$5,000 | $4,500-$7,500 | $6,000-$10,000 |
| Cedar | $20-35 | $4,000-$7,000 | $6,000-$10,500 | $8,000-$14,000 |
| Composite (Trex/TimberTech) | $28-45 | $5,600-$9,000 | $8,400-$13,500 | $11,200-$18,000 |
| PVC (Azek) | $35-55 | $7,000-$11,000 | $10,500-$16,500 | $14,000-$22,000 |
These are decking and substructure costs. Railing, stairs, permits, and site prep are additional.
What Drives the Price Up
Height and access. A ground-level deck with joists sitting on concrete piers is the simplest build. An elevated deck — second story, hillside, or over a walkout basement — requires posts, beams, lateral bracing, and sometimes engineered connections. The substructure for an elevated deck can cost as much as the decking itself. Hillside builds on Portland's west hills add additional engineering and site access costs.
Railing. Wood railing runs $20-40/linear foot installed. Composite railing runs $40-70/linear foot. Cable railing runs $60-100+/linear foot. Metal railing (aluminum or steel) runs $50-120/linear foot. A 300 sq ft deck with railing on three sides needs 50-60 linear feet of railing — that's $1,000-$7,200 depending on the material.
Stairs. A single run of 4-5 steps costs $500-$1,500. A longer stairway from an elevated deck to grade can run $2,000-$5,000. Stairs require their own footings, stringers, and railing, so they're a project within the project.
Permits. Portland requires a building permit for most decks over 30 inches above grade or attached to the house. Permit costs run $300-$800, depending on the project scope. The permit process adds 2-4 weeks to the timeline.
Demolition. Removing an existing deck before building a new one adds $1,000-$3,000 for a standard-size deck. Larger or elevated decks cost more to demo because the substructure requires careful disassembly.
Contractors sit in a work van ready for a project, representing how deck costs vary widely based on scope, materials, and site conditions rather than just the base estimate.
Site conditions. Sloped lots, rocky soil, limited access for equipment, and proximity to trees or structures all increase labor time. Portland's clay-heavy soil can complicate footing excavation — especially in wet months when the ground is saturated.
Cost by Project Type
| Project Type | Typical Range |
|---|---|
| Basic ground-level wood (12x16) | $5,000-$10,000 |
| Mid-range composite (14x20) | $12,000-$22,000 |
| Elevated wood with stairs | $15,000-$25,000 |
| Elevated composite with stairs | $20,000-$35,000 |
| Multi-level or wraparound | $30,000-$50,000+ |
| Deck + covered pergola | $25,000-$45,000+ |
What Should Be in the Quote
A complete deck quote should break down every component:
Footings and substructure. Number of footings, post size, beam size, joist size and spacing, hardware (post bases, joist hangers, structural bolts). This is the skeleton — it should be detailed.
Decking material. Product name, board profile (grooved for hidden fasteners, square-edge for face screwing), and total square footage. Waste factor should be included — typically 10-15% for straight layouts, 15-20% for diagonal or picture-frame patterns.
Railing. Material, style, height (42" is standard residential), post spacing, and infill type (balusters, cable, glass). Railing is often the most visible design element and shouldn't be left as "TBD."
Stairs. Number of runs, tread material, railing, and footings for stair landings. Stairs are frequently under-specified in initial quotes.
Fasteners. Hidden clip systems for composite or stainless/coated screws for wood. The fastener type affects long-term surface appearance.
Permit and engineering. Permit fee, plan submission, and any required engineering (elevated decks in Portland often require stamped plans). The contractor should handle this.
Timeline. Start date, expected completion, and weather contingency language. Portland deck projects in spring often face rain delays — the contract should address how delays are handled.
Frequently Asked Questions
Portland Climate and Material Lifespan
Portland's rain and freeze-thaw cycles affect deck materials differently, and the material choice determines long-term cost as much as the upfront number.
Pressure-treated wood holds up reasonably well but needs annual maintenance. The wood absorbs Portland's rain, swells, then dries and contracts through summer. That cycle loosens fasteners, opens checks in the boards, and lifts grain over time. Sealing every year ($1.50-$2.50/sq ft for a contractor, less for DIY) slows the damage. Skip the sealing for two or three years, and the boards start cupping, splitting, and turning gray. A pressure-treated deck that gets maintained lasts 15-20 years. One that gets ignored starts looking rough by year 5 and needs replacing by year 10-12.
Cedar performs similarly but starts softer. It resists rot better than pressure-treated thanks to natural oils, but those oils deplete over time — especially in Portland's constant moisture. Cedar darkens to gray within one to two years without stain. The maintenance schedule is the same as pressure-treated: annual sealing or staining. Cedar's advantage is its appearance and the feel underfoot. The disadvantage is a higher upfront cost and a shorter lifespan (12-18 years) if maintenance lapses.
Composite decking handles Portland's rain with almost no maintenance. It doesn't absorb water, doesn't check, doesn't splinter. Mold and mildew can grow on the surface in shaded areas, but a once-a-year cleaning with deck wash handles it. The material lasts 25-30 years, with its appearance mostly intact. The tradeoff is a higher upfront cost and a different feel — composite doesn't look or walk like real wood, and it gets noticeably hot in direct summer sun. For most Portland homeowners building a deck they plan to keep for 15+ years, composite decking costs less over the deck's full lifespan than wood.
What the Budget Decides
The deck budget determines the material, the size, and the features — in that order. A $10,000 budget builds a solid 250 sq ft pressure-treated deck with wood railing. A $25,000 budget builds a 300 sq ft composite deck with metal railing and a set of stairs. Knowing where the money goes helps set realistic expectations before the first quote arrives.