Deck Building Cost in Mobile, AL (2026)
Updated October 2026 · Mobile, AL · index 0.88
How much does it cost to build a deck in Mobile? For a 300 sq ft deck with pressure-treated wood, homeowners in Mobile, AL pay about $9,900 on average, and most quotes land between $6,850 and $13,000 — $23 to $43 per sq ft. The price covers plans and the permit, footings, a framed and flashed structure, the deck boards, railing, one set of stairs, fascia and cleanup.
The deck building price in Mobile runs 12% below the U.S. average: construction labor in the Mobile area runs 20% below the national mean, materials 1% below. The same job averages $11,300 nationally and about $9,800 at the Alabama statewide index.
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Deck building price in Mobile by decking material
What a 300 sq ft deck costs in Mobile with each decking material, installed:
| Option | Average · range |
|---|---|
| Pressure-treated woodtreated pine or fir boards, stained and sealed$33 per sq ft | $9,900$6,850 – $13,000 |
| Capped compositehidden fasteners and a picture-frame border$40 per sq ft | $11,900$8,450 – $15,300 |
The least expensive option in Mobile is pressure-treated wood, at about $9,900; capped composite averages $11,900, 1.2 times as much.
Cost to build a deck in Mobile by size
With pressure-treated wood, priced for Mobile, AL:
| Size | Average · range |
|---|---|
| A 200 sq ft deck$36 per sq ft | $7,100$4,850 – $9,350 |
| A 300 sq ft deck$33 per sq ft | $9,900$6,850 – $13,000 |
| A 400 sq ft deck$32 per sq ft | $12,700$8,850 – $16,500 |
Some costs stay the same whatever the size — plans, permit and layout, one set of stairs (4 steps), final inspection and cleanup — so a bigger job costs less per unit: $32 per sq ft for a 400 sq ft deck against $36 for a 200 sq ft deck.
What a deck building in Mobile includes
Line by line, the $9,900 average for a 300 sq ft deck breaks down like this: 47% labor, 53% materials and equipment.
| Line | Low – high |
|---|---|
| Plans, permit and layout | $320 – $970 |
| Ground prep, fabric and gravel | $190 – $490 |
| Footings below the frost line | $360 – $730 |
| Flashed ledger on the house | $220 – $420 |
| 6x6 posts | $240 – $490 |
| Beams | $220 – $420 |
| Joist framing with hangers | $1,250 – $2,150 |
| Deck boards | $1,150 – $1,750 |
| One set of stairs (4 steps) | $450 – $910 |
| Railing | $1,650 – $2,900 |
| Fascia and skirting | $320 – $760 |
| Final inspection and cleanup | $130 – $320 |
| Stain and seal, two coats | $290 – $680 |
Each line is the price book's U.S. rate for that step, scaled by 0.74 to the installed price published sources give for the whole job (see how these prices are built), times Mobile's index of 0.88; permit fees are not scaled.
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What affects deck building prices in Mobile
Labor and materials in Mobile
Construction wages in the Mobile area run 20% below the U.S. mean (BLS, May 2025), and materials in its ZIP codes price 1% below the national average. Together they give Mobile a construction cost index of 0.88.
Where Mobile sits in Alabama
Mobile is the 3rd most expensive of the 4 Alabama cities in our index, against a statewide index of 0.87. Birmingham is the dearest at 0.90; Montgomery is the least expensive at 0.86.
Against the rest of the country
Of the 306 U.S. cities in JobFlex's index, Mobile ranks 287th from the most expensive. The job that averages $9,900 here averages $11,300 at the national rate.
Frost depth in Alabama
Deck footings go below the frost line, or they heave by the second spring. The typical code frost depth in Alabama is about 5 in.. Your building department sets the exact figure.
The deck code in Alabama
There is no statewide code; decks follow the International Residential Code as the cities and counties of Alabama adopt it (Mobile County: 2024 IRC since July 2026; Birmingham: 2021 IRC; the state-level code on record is the 2015 IRC with Alabama changes). Guards are required at 36 in. where the deck is more than 30 in. up, and stair risers can be up to 7.75 in.
What decks are built of in Alabama
Most used on decks in Alabama, Kentucky, Mississippi and Tennessee: treated pine, then capped composite, then cedar.
Sales tax in Alabama
Alabama's base state sales tax is 4%, and cities and counties can add their own. How it applies to a home-improvement contract varies, so ask whether a quote includes it. Prices on this page are before tax.
What a Mobile contractor will ask before quoting
- Reuse the frame or rebuild?
- Height, railing style and stairs
- Board brand and color
Deck building cost in other Alabama cities
A 300 sq ft deck with pressure-treated wood averages $9,900 in Mobile; $10,000 in Huntsville, $9,650 in Montgomery, $10,100 in Birmingham.
| City | Average · range |
|---|---|
| Huntsville, AL1% more | $10,000$6,900 – $13,100 |
| Montgomery, AL2% less | $9,650$6,700 – $12,700 |
| Birmingham, AL2% more | $10,100$7,000 – $13,200 |
deck building price in Mobile: questions
How much does it cost to build a deck in Mobile, AL?
About $9,900 for a 300 sq ft deck with pressure-treated wood, and most Mobile quotes fall between $6,850 and $13,000. That is 12% below the U.S. average, where the same job averages $11,300.
What is the deck price per square foot in Mobile?
$23 to $43 per sq ft, about $33 on average with pressure-treated wood. Smaller jobs cost more per unit, because the fixed costs are spread over less.
How much is a 400 sq ft deck in Mobile?
$8,850 to $16,500, about $12,700 on average, with pressure-treated wood — $32 per sq ft.
Do you need a permit for deck building in Mobile?
Yes — a new deck needs a permit nearly everywhere, Mobile included. In Alabama, decks follow the International Residential Code as the cities and counties of Alabama adopt it (Mobile County: 2024 IRC since July 2026; Birmingham: 2021 IRC; the state-level code on record is the 2015 IRC with Alabama changes). The prices on this page carry $320–$970 for plans, permit and layout.
Does the price include sales tax in Alabama?
No. The prices here are before tax; Alabama's base state rate is 4%, plus any local rate.
What decking do people choose in Alabama?
Most used on decks in Alabama, Kentucky, Mississippi and Tennessee: treated pine, then capped composite, then cedar.
Other home projects in Mobile
Deck building cost in Alabama
How these prices are built
Every price on this page comes from JobFlex's contractor price book: what a homeowner pays a licensed contractor for each step of the job, as a U.S. national average per unit, with the contractor's overhead and profit included and sales tax left out. The deck building is priced step by step, then multiplied by Mobile's construction cost index of 0.88.
Where the price book's steps for an option add up to more than 20% over the installed price a published source gives for the whole job, every step but a permit fee is scaled down to the middle of that range: pressure-treated wood × 0.74 (HomeGuide 2026: $25–$50 per sq ft); capped composite × 0.80 (Ergeon 2026: $30–$60 per sq ft).
The index weighs local construction wages (BLS Occupational Employment and Wage Statistics, May 2025) at 60% and the area's material prices (Craftsman ZIP-area factors) at 40%. Published indices for Mobile, each on its own base: RSMeans residential 0.87, HUD 0.88, Craftsman 0.99. Treat any city figure as about ±5%; a contractor's quote for your house is the number to plan with.
Contractors in Mobile build quotes like these with JobFlex's Deck Studio.
- HomeGuide 2026: pressure-treated deck $25-$50/sqft installed, labor $15-$30/sqft
- Ergeon 2026: composite deck $30-$60/sqft installed
- HomeGuide 2026: composite railing $25-$60/lf, aluminum $50-$200/lf installed