Deck cost calculator for Missouri

How much does a deck cost in Missouri?

A 16 × 12 foot composite deck, 192 square feet with railing and a short flight of stairs, costs $6,780 to $9,170 installed in Missouri, or about $41.55 per square foot. The same deck in pressure-treated pine runs $5,320 to $7,200, in cedar $5,950 to $8,050, and in PVC $7,150 to $9,670.

Missouri labor runs about 12% below the national average, which shifts that composite deck down by roughly $20 against a national-average build. Labor is 40-50% of an installed deck, and it climbs further on elevated or complex-shaped decks where framing takes longer.

Building it yourself removes the labor line: the same composite deck comes to roughly $6,182 in materials, hardware, permit and tool rental. Decks are more forgiving DIY projects than fences in one respect and less in another. The framing is straightforward, but the ledger connection to the house is the single most safety-critical detail in residential construction, and it is the most common inspection failure.

What common deck sizes cost in Missouri

Most people arrive at this deck calculator with a size already in mind, so here are the four that get searched most, priced for Missouri. A 12 × 12 deck (144 sq ft) costs about $6,433 in composite. A 14 × 20 (280 sq ft) costs about $10,737, a 16 × 20 (320 sq ft) about $11,954, and a 20 × 20 (400 sq ft) about $14,387.

In pressure-treated pine those same footprints come down sharply, the 16 × 20 to $9,087 and the 20 × 20 to $10,803. That is the single largest saving available on any deck in Missouri.

Notice how little the per-square-foot figure moves between sizes: $38.35 on the 14 × 20 against $35.97 on the 20 × 20. The permit, the ledger and the stairs cost the same whatever the area, so they spread thinner as the deck grows. If you are undecided between two sizes, the larger one is almost always the better value per square foot.

Building a deck in Missouri

Missouri has a moderate 30-inch frost depth. Deck footings have to reach below that line, and on a 16 × 12 deck that is six to nine footings, so frost depth drives the substructure budget more than any decking choice does.

The climate here is continental with hot humid summers and cold winters, and ground conditions are clay with limestone bedrock close to the surface in many areas. In practical terms: Wide seasonal temperature swings make proper composite gapping important.

Clay soils and freeze-thaw both argue for a compacted gravel base and air-entrained mix. That matters for a deck because every footing is a small concrete pour, and the same constraints that govern a slab govern the piers under your deck.

Composite and Trex decking in Missouri

Composite is the most common upgrade from pressure-treated pine here, and the reason is maintenance rather than price: it never needs sealing, which matters in a climate that is continental with hot humid summers and cold winters. The composite deck calculator setting above prices boards at $9 per square foot, framing at $5 and installed labor at $10 before the Missouri multiplier of 0.88× is applied.

Trex is the brand most people mean when they say composite, and it is sold in tiers rather than at one price: Enhance Basics runs around $5 per square foot for boards alone, Select around $9, and the premium Transcend line around $12. TimberTech, Fiberon and Deckorators compete at each of those tiers. Whichever brand goes down, the framing, railing and labor underneath are identical, which is why installed totals differ far less than board prices suggest.

Wide seasonal temperature swings make proper composite gapping important. Weigh that against how long you plan to stay: over 25-30 years of service the composite deck above works out to $290 per year in Missouri against $501 for pressure-treated pine.

Deck permits and inspections in Missouri

Kansas City and St. Louis both require permits for fences over 6 feet and for decks; shallow limestone can require footing modifications.

Deck permits cost more than fence permits almost everywhere because structural review is involved. Our estimate carries $308 as a permit and inspection allowance for Missouri. Expect at least two inspections: one on the footings before concrete is placed, and one on the framing before decking goes down.

Do not skip the permit on a deck. An unpermitted deck surfaces during resale, and lenders and insurers both take an interest. Rebuilding a deck to code after the fact costs far more than permitting it correctly the first time.

How we calculated these estimates

Every figure on this page comes from the same open formula the calculator above uses. We start from a 2026 national baseline for materials and installed labor, apply the state labor multiplier published by the Bureau of Labor Statistics for construction trades, then add the line items your inputs call for: gates, corners, removal, permits and a waste allowance. Nothing is hidden behind a lead form, and no contractor pays us to appear here. The result is a planning range, not a quote. The low figure assumes straightforward access and an efficient crew, and the high figure assumes obstacles, difficult access, or premium material grades.