Cost to Build a Composite Deck – 2021

| Last Updated: August 21, 2021

National Average Improvement and Repair Cost







$ 7215

$ 3400

Would you do this project? According to our survey, 53% of respondents preferred DIY compared to hiring a pro.

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The average price to Build a Composite Deck noted above is cost data to compare a contractor’s estimate with doing it yourself.

How much does it cost to have a deck built? A deck contractor charges $7,215 to build a composite deck and you can build it yourself for $3,400 and save 52 percent. 

A deck is one of the most popular additions to a house because it expands the living space by incorporating the yard and garden into outdoor living space.

In seasonally warm climates, a deck becomes a favorite place, whether it’s used to read a book, take a nap, dine alfresco or simply enjoy the pleasure of being outside.

Building a deck is no trivial pursuit; it takes a lot of man-hours, not to mention strength and stamina. To build a 300-square-foot ground level deck made of Trex, a composite material made of reclaimed wood and plastic, a contractor will charge $7,215, which includes the labor and material. The material comes in several finishes and color choices, so there’s no finishing required. If you’re an experienced carpenter, have power tools and know how to use them, you can buy the material and fasteners for $3,400 and do it yourself, saving 52 percent.

The building process involves planning the design, laying out the deck for size and height, locating the posts, installing joists and bracing, attaching the deck to the house, installing the foundation piers, installing the decking, and completing the deck with stairs or a railing, if needed.

Before you dive into building a deck, check with your local building department to learn about code requirements. And check your property survey to make sure you know exactly where your property lines are.

To get an idea of different size decks and how they’ll look added to your house use some low-tech visual aids. For example, if you’re considering a 12-by-12-foot deck, spread a drop cloth that size over the lawn where the future deck will be. Or outline the space with a hose and rakes laid down end to end to enclose the space. It’s a far cry from virtual reality, but an easy way to get a feeling for how large (or small) the dimensions will translate to. Consider space for furnishings, outdoor cooking gear, planters and whatever else you want to include.

Wondering how to clean a composite deck? Here’s advice from How to Clean Composite Decking.

Here’s advice from Trex How to Build a Deck.

Now you know the average cost to build a composite deck, which includes the labor and material, and what’s involved, so you can decide to do it yourself or hire a contractor. 

Welcome! We hope you’ll find the job costs of home improvement projects useful when you’re deciding whether to do a job yourself vs. hire a contractor. We’re the authors of 20 home improvement books, most notably Home Improvement for Dummies©, Bathroom Remodeling for Dummies©, Carpentry for Dummies©, Plumbing for Dummies©, and Painting and Wallpapering for Dummies©. Our most recent book Fix It and Flip It is in its second edition. We’ve appeared as home improvement experts on television programs such as CNN, Dateline, the Today Show, HGTV and many others.