How Much Does It Cost to Build a Deck?

Ask three contractors what a new deck costs and you will probably get three very different numbers — and all three could be honest. Decks are priced from a pile of variables: the material on top, the height off the ground, the stairs and railings, the slope of the yard and the labour market where you live. This guide gives you the typical ranges to budget from, a worked example you can check, and the levers that move a quote up or down. Before you compare quotes, measure the deck you want and run the size through our deck calculator, so you know the board, joist and screw counts every price is based on.

The short answer: typical deck prices per square foot

As a rough national guide for the United States in 2025–26, cost guides commonly report the following installed ranges. Read every figure on this page as a typical range that varies by region, material and labour market — never as a quote for your garden, because your site and your city will move the real number.

• Pressure-treated pine: about $25–45 per sq ft installed.
• Cedar: about $35–55 per sq ft installed.
• Composite: about $45–85 per sq ft installed.

Installed means a professional crew, the frame underneath, footings, fasteners and the usual finishing work are all in the number. Cedar sits in the middle because the boards cost more than treated pine. Composite sits at the top because the boards themselves are the expensive part, a theme the FAQ at the end returns to. A simple, ground-level rectangle in a low-cost labour market can land below the middle of each range, while a raised, multi-level build in an expensive city can push past the top of it.

DIY materials-only costs

Building it yourself removes the labour, which is often close to half of an installed price. As a typical materials-only range, expect roughly $12–20 per sq ft for a treated pine deck and roughly $25–40 per sq ft for composite, where the boards and their hidden fasteners push the total up quickly. Materials-only is not the whole DIY bill either: add concrete for footings, joist hangers and structural screws, tool hire or purchase, delivery, and a permit where one is required. If you want the materials list itself before you price anything, our companion guide to working out decking boards, joists, beams and posts goes through every quantity step by step.

Worked example: a 16 × 20 ft deck

A 16 × 20 ft deck covers 320 sq ft, a generous but very common backyard size. Take a professional treated-pine build at a $35 per sq ft midpoint of that typical range: 320 × $35 comes to about $11,200. That is a planning figure built from a typical range that varies by region, material and labour market, so treat it as the centre of a spread, not a promise. At the low and high ends of the treated range, the same deck would plan out at roughly $8,000 to $14,400.

Now the DIY version. Materials at a $15 per sq ft midpoint of the treated materials range come to 320 × $15, about $4,800 — plus tools, footings and your weekends. Tools and weekends are real costs too. Comparing $11,200 with $4,800 is the whole DIY decision in one line: the difference is mostly labour, and whether you would rather spend money or time. Whichever route you take, check the quantities behind the example with the deck calculator before you order a single board.

What drives the price

Two decks with the same footprint can differ in price by half as much again, and the difference is almost never the boards. It is everything underneath and around them.

Height off the ground

A ground-level deck can sit on a simple frame close to the soil. Raise the deck and everything grows: longer posts, deeper and more heavily loaded footings, more bracing, and stairs to get down to the garden. Height also triggers railing requirements in most codes once the surface passes a set distance above the ground, so a raised deck buys two expensive extras — structure and railings — that a low deck avoids entirely.

Stairs and railings

Stairs look small and price large. Even a simple 4-step stair adds a noticeable chunk to a build, because it needs its own stringers, treads, footings and a handrail. Railings are usually priced per linear foot, so a deck wrapped on three sides carries a lot of linear feet. Material matters too: composite railing systems are pricey compared with simple treated timber rails, and metal balusters and post caps add up faster than most people expect.

Ground, access and demolition

A sloping site means stepped footings, longer posts on the low side and more digging. Tight access — no room for a delivery truck or a mini digger — means materials move by hand and spoil moves out by wheelbarrow, and labour hours follow. And if an old deck has to come out first, demolition and disposal are a real line item: posts set in concrete do not leave quietly. None of these show up in a per-square-foot range, which is why ranges are a starting point and site quotes differ.

Permits, inspections and the pattern you choose

Many decks need a permit and one or more inspections, and the fees and the waiting time both belong in the budget. Finally, the pattern on top changes the labour: straight boards are the fastest to lay, while a diagonal layout or a composite picture-frame border adds cuts, blocking under the joints and fixing time on every board. The boards may cost the same — the hours do not.

Reading deck prices in the UK and Australia

Outside the US, decking is usually quoted per square metre rather than per square foot. The conversion is simple: 1 sq ft is about 0.093 m², so the 320 sq ft example deck above is roughly 29.7 m². UK readers should also know that composite dominates the UK market, so expect composite-level pricing rather than treated-pine pricing, and get local quotes — a US range converted to metres is a sense check, not a UK price. The same advice holds in Australia, where board sizes, timbers and labour markets are all local. Everywhere, the rule is the same: use typical ranges to plan, and local quotes to decide.

Where to save money honestly

• Keep it rectangular and ground-level. One rectangle, low to the ground, avoids extra footings, long posts, most railing and complicated cuts in a single decision.
• Build in the off-season. Contractors are quieter in late autumn and winter in many regions and may discount to keep a crew busy — ask, rather than assuming the spring price is the only price.
• Do the demolition yourself. Pulling up an old deck is hard, unskilled work. Doing it yourself, safely, removes a paid line item from the quote.
• Mix materials where they show least. Choose treated boards for the main field and use composite only on the picture-frame border, where it frames the deck and takes the edge wear — the look of composite at a fraction of the board bill.

What not to cut: footings below the frost line, flashing where the deck meets the house, and the permit where one is required. Those three protect the structure and the sale of your home later. Save on shape, timing and sweat instead. When your design is settled, run the final dimensions through our deck calculator one last time, so the quantities in your budget match the deck you are actually building.

Frequently asked questions