DeckMath
Mississippi · 20×12 (240 sqft) · 2026-Q1 retail

20×12 Deck Cost in Mississippi

A 20×12 (240 sqft) deck in Mississippi costs $11,040-$17,760 in mid-tier composite with the state's 0.92× labor multiplier (South). A 12×20 deck (240 sqft) is a long, narrow deck — common for ranch-style homes with a long back wall. Mississippi labor 0.92× national. Coastal humidity + hurricane uplift drives PVC + 316SS hardware on Gulf builds.

240 sqft0.92× laborFrost 6humid climate64 lf perimeter
Area
240 sqft
20×12
PT pine (budget)
$5,520-8,880
$23-37/sqft installed
Mid composite
$11,040-17,760
$46-74/sqft installed
Luxury PVC
$16,560-24,240
$69-101/sqft installed

5 finish tiers — 20×12 in Mississippi

National $/sqft × Mississippi's 0.92× labor multiplier × 240 sqft = total installed cost. Materials + labor + standard railing included.

Tier
$/sqft
Total low
Total high
Budget · Pressure-treated
PT pine
$23-$37
$5,520
$8,880
Mid · Cedar / premium PT
Cedar
$32-$51
$7,680
$12,240
Premium · Mid composite
Trex Transcend, Fiberon Sanctuary
$46-$74
$11,040
$17,760
Luxury · Premium composite
TimberTech AZEK, Trex Signature
$69-$101
$16,560
$24,240
Exotic · Tropical hardwood
IPE, Cumaru
$83-$129
$19,920
$30,960

Excludes permit ($105-$259 typical in Mississippi), demolition (if replacing), and exceptional framing for 6″ frost depth. MS permits $100-180. Hurricane uplift required on coastal counties.

20×12 framing notes for Mississippi

Joist size
2×10 @ 16″ OC
Span 20 ft requires 2×10 SYP or PT pine for IRC R507.6 compliance. Check Joist Span Calculator for exact spans by species + spacing.
Beam configuration
2-3 beams
A 20×12 deck typically needs 2-3 beams depending on whether you can drop joists onto the beam (1) or hang them flush (2+).
Post count
6 posts
6×6 PT posts at 6-post layout typical. Footings extend below 6″ frost line.
Footings
6 × 6″ deep
Sonotube 10-12″ diameter at 6″ depth per IRC R403.1.4. Concrete budget: ~$248.
Decking
396 lf
240 sqft × 1.65 lf/sqft = 396 lf of deck boards at 16″ joist OC. Add 5-7% waste for cuts.
Railing
64 lf perimeter
64 lf of railing (~$36/lf mid composite, ~$22/lf wood). Stairs need 2 extra handrails (1 each side).

Mississippi considerations

Labor multiplier
0.92×
South region labor pricing on all installed costs.
Frost depth
6″
Footings extend below frost line per IRC R403.1.4. Standard footing depth.
Climate
humid
Salt-air coastal: use 316SS hardware. Lean composite over PT for 25-yr TCO.
Top metros
Jackson · Gulfport
Major metros drive installer availability + pricing pressure.
Permit fee
$105-$259
MS permits $100-180. Hurricane uplift required on coastal counties.
Region
South
South regional pricing applied. Multiply national $/sqft by 0.92× for Mississippi installed cost.

Get a precise quote for your 20×12 deck in Mississippi

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FAQ — 20×12 deck in Mississippi

How much does a 20×12 deck cost in Mississippi?

In Mississippi, a 20×12 (240 sqft) deck costs $5,520-$8,880 in pressure-treated, $11,040-$17,760 in mid-range composite (Trex Transcend / Fiberon Sanctuary), and $16,560-$24,240 in luxury composite/PVC (TimberTech AZEK / Trex Signature). Numbers reflect Mississippi's 0.92× labor multiplier on 2026-Q1 retail.

What's the cheapest way to build a 20×12 deck in Mississippi?

Cheapest = ground-level pressure-treated pine with no railings (where exempt under 30″ height) — ~$4,416-$6,624 in Mississippi. Add stairs + railings + above-grade framing and the build goes to ~$6,182-$8,832. DIY saves 30-50% on labor but requires permit + inspection coordination yourself.

How long does it take to build a 20×12 deck in Mississippi?

Permit timeline in Mississippi: 2-6 weeks depending on jurisdiction. Construction time for a 20×12: 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 20×12 deck in Mississippi?

IRC R507-compliant framing for a 20×12 deck typically uses 2×8 joists at 16″ OC for spans up to 12 ft, 2×10 joists for spans 12-16 ft. Mississippi's frost depth is 6″ — footings must extend below that per IRC R403.1.4. Sonotube 10-12″ diameter at 6″ depth is typical. Verify with your local building department.

Is composite worth it for a 20×12 deck in Mississippi?

Over 25 years in Mississippi: PT pine = ~$6,624 install + ~$13,800 maintenance (stain every 2-3 yr) = $20,424 total. Mid composite = ~$12,806 install + $0 maintenance = $12,806 total. Composite wins by 59-81% over 25-yr lifecycle PLUS better resale value in Mississippi's market.

Compare Mississippi brand pricing for a 20×12

Same 20×12 in other states