20×20 Deck Cost in Maryland
A 20×20 (400 sqft) deck in Maryland costs $18,400-$29,600 in mid-tier composite with the state's 0.92× labor multiplier (South). A 20×20 square deck (400 sqft) is a favorite for outdoor kitchens + dining + lounge — the smallest size where 3 zones comfortably coexist. Maryland labor 0.92× national. Chesapeake humidity favors composite.
5 finish tiers — 20×20 in Maryland
National $/sqft × Maryland's 0.92× labor multiplier × 400 sqft = total installed cost. Materials + labor + standard railing included.
Excludes permit ($105-$259 typical in Maryland), demolition (if replacing), and exceptional framing for 30″ frost depth. MD permits $200-350. Critical Area Commission reviews for waterfront decks.
20×20 framing notes for Maryland
Maryland considerations
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FAQ — 20×20 deck in Maryland
How much does a 20×20 deck cost in Maryland?▾
In Maryland, a 20×20 (400 sqft) deck costs $9,200-$14,800 in pressure-treated, $18,400-$29,600 in mid-range composite (Trex Transcend / Fiberon Sanctuary), and $27,600-$40,400 in luxury composite/PVC (TimberTech AZEK / Trex Signature). Numbers reflect Maryland's 0.92× labor multiplier on 2026-Q1 retail.
What's the cheapest way to build a 20×20 deck in Maryland?▾
Cheapest = ground-level pressure-treated pine with no railings (where exempt under 30″ height) — ~$7,360-$11,040 in Maryland. Add stairs + railings + above-grade framing and the build goes to ~$10,304-$14,720. DIY saves 30-50% on labor but requires permit + inspection coordination yourself.
How long does it take to build a 20×20 deck in Maryland?▾
Permit timeline in Maryland: 2-6 weeks depending on jurisdiction. Construction time for a 20×20: pro crew = 5-8 days for framing + boards + railings + stairs. DIY = 3-5 weekends for experienced DIYer. Allow extra time for permit approval + inspections.
What framing do I need for a 20×20 deck in Maryland?▾
IRC R507-compliant framing for a 20×20 deck typically uses 2×8 joists at 16″ OC for spans up to 12 ft, 2×10 joists for spans 12-16 ft. Maryland's frost depth is 30″ — footings must extend below that per IRC R403.1.4. Sonotube 10-12″ diameter at 30″ depth is typical. Verify with your local building department.
Is composite worth it for a 20×20 deck in Maryland?▾
Over 25 years in Maryland: PT pine = ~$11,040 install + ~$23,000 maintenance (stain every 2-3 yr) = $34,040 total. Mid composite = ~$21,344 install + $0 maintenance = $21,344 total. Composite wins by 59-81% over 25-yr lifecycle PLUS better resale value in Maryland's market.