How Much Does a New Deck Cost in St. Louis? (The 2026 Honest Answer)

Type "how much does a new deck cost" into a search bar and you'll get answers ranging from $4,000 to $60,000 — which is another way of saying you'll get no answer at all. National averages blend a 10x10 pressure-treated platform in rural Georgia with a multi-level composite build in Chicago, and neither one is your backyard.

So here's the answer the way we give it across the table in Fenton, Ballwin, and Chesterfield — real 2026 St. Louis pricing, the honest framework behind it, what rebuilds and renovations cost compared to new builds, and a straight take on the question underneath all of it: how much should a new deck cost, and how do you know when a number is wrong?

The Short Answer First

New decks in the St. Louis area run $35–$75 per square foot installed, depending on materials and complexity. In whole-project terms:

• Basic new deck (pressure-treated, 300-400 sq ft, single level, standard railing): $15,000 – $25,000
• Mid-range new deck (composite decking, 300-500 sq ft, quality railing, some design detail): $25,000 – $50,000 — a typical composite deck lands between $20,000 and $35,000
• Premium new deck (large or multi-level, premium composite or PVC, aluminum or cable railing, built-ins, lighting): $50,000 – $80,000+

Those ranges are wide because decks are genuinely custom — the rest of this post is about what moves your project up or down inside them, which is the part the national averages can't tell you.

Where the Money Actually Goes

A deck budget splits into rough thirds, and knowing the split explains most pricing questions:

The structure (roughly 30-35%): footings, posts, beams, joists, hardware, and the ledger connection to your house. This is pressure-treated lumber regardless of what goes on top, and it's where safety lives — proper frost-depth footings, correct ledger flashing and fastening, and joist spacing matched to your decking material. It's also the part you can't see at the open house and the part that determines whether the deck is still solid in year twenty.

The surface and rails (roughly 40-50%): decking boards and the railing system. This is where material choice swings the budget hardest. Pressure-treated decking is the value floor; quality composite runs 2-3x the board cost but eliminates staining, sealing, and splinter cycles for decades; premium composite and PVC lines climb from there. Railings are the sleeper line item — standard wood rail is cheap, but the black aluminum balusters, drink rails, and cable systems everyone actually wants can run $60-$150+ per linear foot installed, and a typical deck has a lot of linear feet.

Labor, design, and permits (roughly 25-30%): design, engineering where required, permit fees and inspections, demolition of any existing structure, and skilled installation. St. Louis-area municipalities permit and inspect decks — footing inspections happen with holes open, before concrete. A quote without permits in it is telling you something about how that builder operates.

What Moves Your Number Up or Down

The five levers, in order of impact:

1. Size — but less than you'd think. Cost per square foot drops as decks get bigger, because footings, stairs, and railing don't scale linearly. A 500 sq ft deck is not 25% more than a 400 sq ft deck. If you're between sizes, the bigger version is usually the better per-foot value.

2. Decking material. The pressure-treated vs. composite decision is the single biggest line-item swing — and it's really a maintenance-budget decision. Wood costs less on day one and then asks for cleaning, staining, and board replacement every couple of years for its whole life. Composite costs more once. Over 15 years, the totals converge; the difference is whether you pay in money now or in weekends forever.

3. Height and terrain. A deck 2 feet off grade and a deck 9 feet off grade on a sloped lot are different projects — taller structures mean bigger posts, more bracing, longer stairs, and often engineering. Walkout-basement homes in Wildwood and Chesterfield know this one well.

4. Railing selection. See above — this is the line where budgets quietly grow $5,000 without anyone noticing until the proposal arrives. Decide your railing tier early.

5. The extras. Built-in benches and planters, picture-frame borders, integrated lighting, privacy screens, pergolas overhead. All worth having, all honest adders — the key is choosing them deliberately rather than discovering them in change orders.

Rebuild vs. Renovation vs. New: Which One Is Your Project?

Half the "new deck" conversations we have turn out to be about an existing deck — so here's the honest sort, since the pricing differs meaningfully:

Deck renovation — $4,000 – $15,000. The frame is sound; the surface is tired. We replace decking boards and railings on the existing structure, tighten and re-flash the ledger, and update stairs. This is the right project when a professional inspection confirms the substructure is genuinely healthy — posts solid, joists sound, footings stable, ledger properly attached. Resurfacing a good frame with composite is one of the best value plays in outdoor remodeling: most of the new-deck look for roughly a third of new-deck money.

Deck rebuild — $18,000 – $45,000+ (roughly new-deck pricing, minus nothing, plus demolition). The frame is the problem — rot in the posts or joists, undersized framing, failing footings, or a ledger connection from an era before modern attachment standards. Here's the honest part contractors sometimes soften: a rebuild costs about the same as a new deck, plus $1,500-$4,000 of demolition and disposal. You can't put new boards on a failing frame and call it renovated; the frame is the deck. If your deck is 20+ years old and was builder-grade to begin with, budget for a rebuild and let the inspection surprise you pleasantly, rather than the reverse.

Which one you actually need comes down to a substructure inspection — 30 minutes with someone who knows what ledger failure and joist rot look like. We do these free, and the answer changes the budget conversation by tens of thousands of dollars, so it's the first step, not an afterthought.

How Much SHOULD a New Deck Cost? (Reading Quotes Like a Contractor)

The question behind the question: when you have three quotes in hand, how do you know which number is right?

A quote meaningfully below the ranges above is a question, not a win. The usual explanations: no permit (you own that problem at resale), undersized or shallow footings (you own that problem the first February), pier blocks instead of poured footings, minimal ledger fastening, or a crew that won't exist when the warranty question arises. St. Louis frost depth and clay soils are not the place to discover footing shortcuts — concrete work here follows cold-weather and depth standards for physical reasons, not bureaucratic ones.

A quote meaningfully above the ranges should be explainable line by line: premium materials, difficult site, engineering, high railing spec. "Explainable" is the standard — a good builder can walk you through exactly where every thousand lives.

The comparison discipline: make sure all three quotes price the same decking line, the same railing system, the same footing spec, and all include permits and demo. Most "cheap" quotes are cheaper scope, not cheaper skill.

How Hard Is It to Build a Deck Yourself? (The Honest DIY Answer)

Fair question, honestly answered: the decking is easy; the deck is hard.

Laying boards on a finished frame is satisfying weekend work, and it's the part every DIY video shows. What the videos skip is everything below and behind it: digging and pouring frost-depth footings (30+ inches here, below the frost line), sizing beams and joists to span tables, attaching a ledger to the house correctly (improper ledger attachment is the classic cause of deck collapses — it's the first thing inspectors and deck-safety organizations check), building code-compliant stairs and railings (the most-failed inspection items), and pulling the permit that makes all of it legal and insurable.

The realistic DIY math: a capable DIYer building a simple 300 sq ft ground-level deck saves perhaps 30-40% of project cost, spends 4-8 full weekends, and takes on the structural learning curve personally. For low platform decks, that can be a fine trade. For anything elevated, attached to the house, or supporting gatherings of people — the honest answer is that the structure is where professional value lives, and it's exactly the part you can't redo easily when it's wrong.

The middle path some handy homeowners take: we build the permitted structure; they finish decking and trim. Ask about it — it's a legitimate way to trade sweat for budget without owning the structural risk.

The Timeline Footnote

Pricing is only half the planning math — the calendar is the other half, and we published the honest version of it in our deck deadline post: contract timing, permit clocks, and the concrete-season window that governs when footings can go in. Short version: pricing doesn't change much by season here, but schedule position does, dramatically. Read that one next if a this-year deck is the goal.

Frequently Asked Questions

How much does a new deck cost?

In St. Louis in 2026: $35-$75 per square foot installed, with most complete projects landing between $15,000 (basic pressure-treated) and $50,000 (quality composite with good railings), and premium builds above that. Material choice, height, and railing selection are the biggest swings — see the full breakdown above.

How much should a new deck cost?

It should land inside the ranges above for the scope quoted, with every deviation explainable line by line. Quotes far below market usually mean missing permits, footing shortcuts, or thinner scope rather than a bargain — compare quotes on identical specs, and treat unexplainable cheapness as risk, not savings.

How much does it cost to rebuild a deck?

Roughly the same as building new — $18,000-$45,000+ for typical projects — plus $1,500-$4,000 for demolition and disposal of the old structure. Rebuilds price like new builds because the frame is most of the work; there's no meaningful discount for the old deck having existed.

How much does a deck renovation cost?

If the substructure is sound: $4,000-$15,000 to replace decking and railings on the existing frame — the highest-value version of deck work when an inspection genuinely supports it. The inspection is the gate: renovating over a failing frame just puts new boards on a problem.

How hard is it to build a deck?

The surface is DIY-friendly; the structure is not. Footings, framing spans, ledger attachment, stairs, and railings are where safety, code, and inspections live — and where mistakes are expensive or dangerous. Honest rule: ground-level platforms are reasonable DIY; anything elevated or house-attached earns professional structural work, even if you finish the decking yourself.

Get Your Real Number

Every range above narrows to one real number after a walkthrough of your actual yard — size, height, material, railing tier, and whether your project is a renovation, a rebuild, or a new build. If you have an existing deck, we'll start with the free substructure inspection and tell you honestly which project you have.

Covenant Contracting designs and builds decks across the St. Louis metro — Fenton, Wildwood, Ballwin, Chesterfield, St. Peters, Grover, Valley Park, and surrounding areas. Free consultations, line-item proposals, permits always included.

Request Your Free Deck Consultation →

Or call (314) 282-1991.