How much does a screen porch / three-season room addition cost in Seattle?

A screen porch / three-season room addition in Seattle typically costs $9,589-$41,950, 20% above the $18,000 national average.

What is the cost per sq ft for a screen porch / three-season room addition in Seattle?

Screen Porch / Three-Season Room Addition in Seattle typically costs $48-$180 per sq ft.

How long does a screen porch / three-season room addition take?

A screen porch / three-season room addition typically takes 3-6 weeks. The minimum timeline is 1-2 weeks, and complex projects can run 8-12 weeks.

Can I DIY a screen porch / three-season room addition?

DIY feasibility for a screen porch / three-season room addition is rated Low to Moderate - Screen porch additions involve structural framing, roofing, and electrical work that all require permits. An experienced carpenter can handle framing and possibly roofing, but the electrical, permit process, and connection to the house structure are better left to professionals..

Cost to Screen Porch / Three-Season Room Addition in Seattle, WA (2026)

If you’re budgeting a screen porch / three-season room addition in Seattle, most projects run $9,589-$41,950, 20% above the $18,000 national average. What moves that number most is usually one thing: Square Footage. On its own it can swing the cost by $5,000 - $40,000, so that’s the decision to slow down on before you sweat the smaller stuff.

Easiest place to save: Build over an existing deck or concrete patio. You eliminate new foundation costs of $2,000-$5,000 and the existing floor is already there.

$9,589-$41,950 in Seattle

20% above the national average · 1.20x cost multiplier

In Seattle, a screen porch / three-season room addition runs $9,589 to $41,950 on average - about 20% above what homeowners pay nationwide. The West Coast market's labor costs account for most of the gap, with material pricing and local permitting fees adding to the spread. Use the cost table below to compare budget, mid-range, and premium options side by side.

Cost Breakdown in Seattle

Line Item	Low	Mid	High
Cost per sq ft	$48	$108	$180
Materials	$5,130	$10,830	$25,080
Labor	$4,868	$10,249	$23,061
Permits	$570	$912	$1,710
Total	$10,568+20% vs. national avg	$22,789+20% vs. national avg	$52,701+20% vs. national avg

Budget

Basic 12x16 (192 sq ft) screen porch added to existing deck - wood framing, aluminum screening, simple shed roof, no electrical

Mid-Range

16x20 (320 sq ft) three-season room with composite decking, ceiling fans, recessed lighting, screen or EZE-Breeze panels, proper footing

Premium

20x24 (480 sq ft) fully enclosed three-season room with vaulted ceiling, bead board ceiling, ceiling fans, built-in outdoor kitchen bar, premium windows or screen systems, full electrical

Material Options

Material prices below are national averages; availability in Seattle may shift costs slightly.

Material	Cost/Unit	Pros	Cons	Best For
Standard Aluminum Insect Screening	$1 - $3 per sq ft of screen area	Lowest cost, good visibility, allows full airflow, easy to repair	Seasonal use only (cold climates), tears over time, no protection from cold or rain without separate panels	Warm climates or homeowners who primarily want insect protection during summer monthsLowest cost, good visibility, allows full airflow, easy to repair
EZE-Breeze Vinyl Track Panels	$8 - $15 per linear foot	Convertible between screen and enclosed panel, extends season significantly, keeps out rain and wind	More expensive, requires regular cleaning, panels can yellow over time	Homeowners in mixed climates who want to use the porch spring through fallConvertible between screen and enclosed panel, extends season significantly, keeps out rain and wind
Fiberglass Screening	$1.50 - $4 per sq ft	More durable than aluminum, better UV resistance, doesn't crease as easily	Slightly less visibility than aluminum, similar cost range	High-traffic porches or pet households where durability is a priorityMore durable than aluminum, better UV resistance, doesn't crease as easily
Composite Decking Floor	$8 - $15 per sq ft installed	Low maintenance, durable, no painting or staining needed, fade-resistant	Higher upfront cost than wood, can get hot in direct sun	Three-season rooms and porches that will see heavy use and need low-maintenance flooringLow maintenance, durable, no painting or staining needed, fade-resistant
Pressure-Treated Wood Frame and Floor	$4 - $8 per sq ft for flooring	Lower cost, natural look, easy to repair, widely available	Requires periodic painting or staining, can crack or splinter over time, more maintenance than composite	Budget-conscious builds where maintenance is acceptableLower cost, natural look, easy to repair, widely available

Other Projects in Seattle

Full Kitchen Remodel

Full Bathroom Remodel

Composite Deck Building

Back to national average for Screen Porch / Three-Season Room Addition

Seattle Estimate

Typical Range

$9,589-$41,950

vs. National Average

20% above national

Cost Multiplier

1.20x

Cost Per sq ft

$48-$180

This 1.20x estimate prices Seattle labor from BLS Occupational Employment and Wage Statistics (May 2025) and applies a lighter regional adjustment to materials and permits, which vary less by metro than labor does. Actual bids vary by contractor, project scope, and timing.

See national average costs →