A 20x20 deck gives you 400 square feet of usable outdoor living space, enough for a full dining set, a lounge area, and room to move. It is one of the most popular sizes we build for Lake Norman homeowners. The honest answer to what it should cost depends mostly on the decking material, the height off the ground, and the railings and stairs you choose. Here is what a 20x20 deck actually costs in 2026.
The short answer
For a standard 20x20 (400 sq ft) deck near Lake Norman, expect roughly $19,200 for pressure-treated wood and around $24,000 for composite, with premium or elevated composite builds running $30,000 and up.
That works out to about $48 per square foot for pressure-treated and $60 per square foot for composite, installed. Those numbers include the substructure, decking, fasteners, standard railings, and labor.
Pressure-treated vs. composite for a 400 sq ft deck
Pressure-treated southern yellow pine is the most budget-friendly option and remains a solid choice when it is built well and sealed regularly. At our rate of about $48 per square foot, a 20x20 pressure-treated deck lands near $19,200.
Composite decking from Trex or TimberTech costs more up front, around $60 per square foot or roughly $24,000 for the same 20x20 footprint, but it never needs staining or sealing and stands up far better to Lake Norman humidity, sun, and moisture. Over a 25-year life, most lakefront homeowners find composite is the better value.
What changes the price
Height off the ground is the biggest swing factor. A ground-level 20x20 deck costs far less than a second-story walkout that needs taller posts, more bracing, and a longer stair run.
Railings, stairs, lighting, built-in benches, and curved or multi-level designs all add to the total. So does difficult site access on sloped lakefront lots. We give every Lake Norman homeowner a detailed, itemized estimate so there are no surprises.
Frequently Asked Questions
How much is a 20x20 pressure-treated deck?
Around $19,200 installed near Lake Norman in 2026, or about $48 per square foot including substructure, decking, railings, and labor.
How much is a 20x20 composite deck?
About $24,000 for standard composite, with premium or elevated builds running $30,000 and up.
Is a 20x20 deck big enough?
Yes. At 400 square feet it comfortably fits a dining table, a seating area, and a grill with room to move, which is why it is one of the most popular sizes we build.
Want an exact price for your lot? Lakeshore Decks Construction provides free, detailed 20x20 deck estimates across the Lake Norman area.
