How Much Does it Cost to Build a 16x20 Composite Deck?

Building a 16×20 composite deck can cost between $6,720 and $24,640. The average cost is around $49 per square foot, including materials and labor. Factors affecting the total cost include the quality of the composite material, design complexity, and additional features like railings or built-in seating.

composite deck building costs based on the type:

• Ground-Level / Platform (Attached): $52 – $65 per square foot
• Detached / Floating (Freestanding, no railings, no stairs): $39 – $52 per square foot
• Elevated (Attached): $65 – $104 per square foot
• Second-Story (Attached): $104 – $130 per square foot
• Multi-Level (Attached): $117 – $169 per square foot

A ground-level or platform deck is typically less than 30″ to 36″ tall, attached to the home at the back door, and may include optional railings. These decks are perfect for easy access to your backyard and can serve as a seamless extension of your indoor living space. Costs increase with the number of steps and if reinforced footers are needed. Adding features like built-in seating, planters, or lighting can also enhance the functionality and aesthetics of the space.

A detached or floating deck doesn’t need railings, stairs, or deep footers extending below the frost line. This lightweight deck usually rests on gravel and concrete blocks, making it an affordable and quick-to-install option. These decks are ideal for creating a separate lounging or dining area away from the main house, offering more versatility in your yard layout. Many states don’t require permits for these decks because they aren’t attached to the home, simplifying the construction process and reducing costs.

An elevated deck stands at least 3 feet above the ground but below the second story. It has a reinforced concrete base and must have railings according to building codes to ensure safety. Elevated decks provide a great vantage point to enjoy your surroundings and are perfect for sloped yards where a ground-level deck might not be feasible. They often include stairs leading down to the yard, which can add to the cost but also enhance accessibility. You can further customize these decks with pergolas, awnings, or even a built-in outdoor kitchen for more functionality.

A second-story deck is popular because it creates a covered porch underneath, offering additional outdoor living space that’s sheltered from the elements. It requires large pillars and reinforced foundations for support, which can drive up costs. These decks are excellent for providing direct access from upper-floor rooms and can be designed to blend seamlessly with the architecture of your home. They often include features like staircases to the ground level and can be enhanced with railings, lighting, and even glass panels for a more modern look.

A multi-level deck is the most expensive option, ideal for multi-story homes. These attached decks offer multiple dining and lounging areas, enhancing your outdoor entertainment space. Each level can serve a different purpose, such as a dining area, a lounging zone, or a play area for children. The complexity of constructing these decks, including the need for multiple sets of stairs, railings, and support structures, increases the cost significantly. However, the investment pays off by providing a luxurious and versatile outdoor space that can accommodate various activities and gatherings. Custom features like built-in fire pits, hot tubs, or water features can further enhance the appeal and functionality of a multi-level deck.

On average, labor costs to build a composite deck range from $31 to $62 per square foot. These fees are generally higher than those for wooden decks because composite materials require more precise assembly and additional components. The extra care needed during installation ensures the durability and longevity of the deck, justifying the higher labor costs.

The color and texture of your deck can significantly impact the cost. Complex designs and wood-like textures tend to be the most expensive due to the intricate manufacturing processes involved. On the other hand, basic colors and simpler designs are more budget-friendly. If you’re looking for a custom design or unique color blend, be prepared to pay a premium. Additionally, intricate patterns or inlays can add to the overall cost, but they also provide a unique aesthetic appeal that can enhance your outdoor space.

Capped composite decking has an outer layer that provides superior resistance to moisture, fading, and staining, making it more durable and low-maintenance. This added layer of protection, however, comes at a higher price. Uncapped composite decking is less expensive but may require more maintenance over time to keep it looking its best. The choice between capped and uncapped decking will depend on your budget and how much maintenance you’re willing to perform.

Hollow composite decking is lighter and generally less expensive, making it a good option for budget-conscious projects. However, solid composite decking offers greater strength and durability, which can be important for high-traffic areas or structures that need to support more weight. Solid boards also tend to have a more natural look and feel, which can be a deciding factor for many homeowners. While solid boards are more expensive, their longevity and strength can make them a worthwhile investment.

Hollow composite decking is lighter and generally less expensive, making it a good option for budget-conscious projects. However, solid composite decking offers greater strength and durability, which can be important for high-traffic areas or structures that need to support more weight. Solid boards also tend to have a more natural look and feel, which can be a deciding factor for many homeowners. While solid boards are more expensive, their longevity and strength can make them a worthwhile investment.

The type of fasteners you choose can also affect the overall cost of your deck. Traditional fasteners, like screws and nails, are more affordable and quicker to install. Hidden fasteners, however, provide a cleaner, more seamless appearance but can increase installation time and cost. Hidden fasteners can prevent visible screw heads and offer a smoother walking surface, which many homeowners find appealing. The decision between traditional and hidden fasteners will depend on your budget and desired aesthetic.

In colder climates, it’s crucial to install concrete footers below the frost line to prevent shifting and instability. Wooden deck posts should not be buried directly in the ground, as this can lead to rot and compromise the deck’s structural integrity. Instead, they should be mounted on concrete footers to ensure longevity. This additional step can increase the overall cost but is essential for ensuring the deck’s durability and safety, particularly in regions with harsh weather conditions.

Proper drainage is essential for maintaining the longevity of your deck. Installing a drainage system for a ground-level deck can cost between $1,300 and $5,200. Without adequate drainage, water can pool around the deck supports, leading to rot and structural damage over time. A good drainage system helps prevent these issues, ensuring that your deck remains safe and sturdy. This investment can save you from costly repairs in the future and extend the life of your deck.