Wednesday, October 25, 2023
As the best outdoor living space for entertaining and relaxing, outdoor composite decking is gaining more and more recognition. As one of the best alternatives to wood decking, this new construction and decorative material offers homeowners more convenience. So how much does it cost to build a 20×20 composite decking?
Table of Contents
Composite decking board materials cost between $16 and $32 per square foot. Labor costs to install composite decking range from $24 to $48 per square foot. Therefore, including the substructure, the cost of installing composite decking is between $40 and $80 per square foot. Ultimately, a 20’x20′ composite decking can cost between $16,000 and $32,000 to build.
| Deck size (feet) | Square feet | Average cost installed* |
|---|---|---|
| 8’x10′ | 80 | $3,200 – $6,400 |
| 10’x10′ | 100 | $4,000 – $8,000 |
| 10’x12′ | 120 | $4,800 – $9,600 |
| 12’x12′ | 144 | $5,750 – $11,500 |
| 12’x14′ | 168 | $6,700 – $13,450 |
| 12’x16′ | 192 | $7,680 – $15,350 |
| 12’x18′ | 216 | $8,650 – $17,280 |
| 12’x20′ | 240 | $9,600 – $19,200 |
| 14’x20′ | 280 | $11,200 – $22,400 |
| 16’x16′ | 256 | $10,250 – $20,480 |
| 20’x20′ | 400 | $16,000 – $32,000 |
| 20’x24′ | 480 | $19,200 – $38,400 |
| 24’x24′ | 576 | $23,000 – $46,000 |
The following table shows the cost of building different types of outdoor composite decking:
| Deck design type | Cost per square foot installed* |
|---|---|
| Ground-level / platform (Attached) | $40 – $50 |
| Detached / floating (Freestanding, no railings, no stairs) | $30 – $40 |
| Elevated (Attached) | $50 – $80 |
| Second-story (Attached) | $80 – $100 |
| Multi-level (Attached) | $90 – $130 |
This type of outdoor deck is usually less than 30 inches and 36 inches in height. They are attached to the house at the back door and can have deck railings installed if desired. Depending on the number of steps and whether or not the foundation needs to be reinforced, the cost of deck installation can go up.
Freestanding or floating decks do not require railings, stairs, or deep page feet below the frost line. Often, these lightweight decks are supported only by dirt and concrete blocks. In many places, these types of decks do not require a permit because they are not attached to the house.
Elevated decks are at least three feet above the ground and below the second story. The base of this type of deck is usually made of reinforced concrete, and building codes also require it to be fitted with deck railings.
This type of outdoor deck is popular because it creates a shaded porch below. This type of deck requires large columns and sturdy supports.
This is also the most costly outdoor deck and is most popular in homes with two or more levels. Multiple levels of connected decks can connect more outdoor recreational areas.
Labor costs to build composite decking are higher than wood decks because they require more care in assembly and have more parts. Typically, the labor cost to hire someone to install composite decking ranges from $24 to $48 per square foot.
| Factor | Cost per square foot* |
|---|---|
| Materials | $16 – $32 |
| Labor | $24 – $48 |
| Total cost to install | $40 – $80 |
The relevant cost factors are listed below:
Project costs are influenced by the color and texture of the decking surface. Composite decking that has an intricate pattern design and texture of wood costs the most. Those choosing the most basic colors and patterns cost the least.
Capped composite decking costs more than uncapped composite decking because they have an additional protective polymer layer on the outside that makes them more resistant to the elements.
Hollow composite decking is strong enough for most applications. Solid composite decking is more costly and tougher.
Traditional fasteners are faster and less expensive, while hidden fasteners look better but take longer to install and cost more.
In cold locations, concrete footings should be below the frost line. Builders should not bury wooden deck struts as they will rot.
Installing a new drainage system costs at least $1,000 to $4,000. A yard drainage system is important so that standing water does not rot the deck supports.
The cost increases further if a drainage and runoff system is installed underneath the second-story deck.
Pea gravel ranges from $0.85 to $2.80 per square foot. Gravel under a raised deck or second-story deck prevents weeds from growing and helps water runoff.
Adding vinyl or wood railing to composite decking costs $20 to $60 per foot.
Installing deck stairs costs $20 to $30 per square foot, plus $80 to $160 for a concrete foundation.
It costs approximately $500 to $1,000 to level a yard before building an outdoor deck project.
Labor costs are higher in cities with high demand for deck building than in rural or less expensive locations.
Depending on the size of the deck and the building regulations in your area, permits can range from $50 to $150.
A structural engineer who looks at the site and develops plans will cost $100 to $220 per hour for labor. If the building plans are large or complex, an engineer’s specialized design is required to obtain a permit.
Installation of special features that add to outdoor living requires additional fees, such as
Purchasing composite decking boards can cost between $4 and $16 per square foot. Footings, steps, railings, and substructures will cost extra. Most composite decking is made of polyethylene.
This type of composite decking looks most like solid wood. However, PE and HDPE decking will retain more heat, so light-colored composite decking is recommended for sunny areas.
Looks more like plastic. This material comes in a variety of colors. However, it expands and contracts with temperature and is more prone to mold than polyethylene plastic decking.
Polypropylene decking can handle extreme heat better than other types of composite decking. This material won’t buckle when wet for long periods of time, but it can easily break in cold places.
The price of each brand of composite decking boards is shown in the table below:
| Composite decking brand | Material prices per square foot* |
|---|---|
| COOWIN | $2 – $4 (factory direct price) |
| Veranda | $3 – $8 |
| Genovations | $4 – $7 |
| Deckorators | $5 – $9 |
| Trex decking | $5 – $15 |
| Envision | $5 – $16 |
| Gorilla | $6 – $12 |
| Timebertech / Azek | $6 – $13 |
| CertainTeed | $7 – $9 |
| Fiberon | $7 – $14 |
The cost to install composite decking is $40 to $80 per square foot. The cost to build a wood deck is $25 to $50 per square foot. While composite decking material has a higher upfront cost, it does not require resealing and lasts longer than many types of wood.
| Composite decking | Wooden decking |
|---|---|
| $40 to $80 per square foot installed | $25 to $50 per square foot installed |
| Lasts 25 to 50 years | Lasts 10 to 25 years |
| Low maintenance | Needs regular maintenance |
| Many color & grain options to imitate wood | Natural look of wood |
| Doesn’t rot & repels termites | Choice to stain or paint a new color |
| Difficult to change colors |
Composite decking is a decorative product produced by mixing wood fibers and plastic. It is a durable alternative to wood decking. Some composite decking is made entirely of plastic, while others are made from more recyclable plastics and chemicals, making them longer lasting and more UV resistant.
Composite decking is a great option for people who want a deck that doesn’t require much care. Composite decking materials also won’t fade, scratch, or rot, and they’re also resistant to pests. In addition, they won’t warp or crack like wood decks.
When properly maintained, composite deck boards typically last between 25 and 50 years. This depends on the brand, installation, weather, and foot traffic. Regularly check your decking for loose parts and keep it dry and free of dirt to extend its life.
Composite decking can increase the value of your home because it is both beautiful and durable. This low-maintenance outdoor deck is especially attractive to buyers.
If you are purchasing an uncapped composite decking, you can paint or stain it. A capped composite decking with a polymer shell cannot be colored or painted. Painting some brands of composite deck boards may also void the warranty.
You can power wash your composite decking, but only use very low pressure to avoid damaging the deck surface. Before you begin cleaning, spray the water at a gentle angle and read the cleaning instructions that come with the product.
Most composite decking is not slippery when wet, but it varies by brand. Most companies add a non-slip layer to prevent people from falling. On the other hand, cheaper brands may not have a good protective layer. To maintain the non-slip feature, the deck needs to be cleaned frequently.
If you are not planning to install composite decking yourself DIY, here are some questions you can ask a professional deck contractor when you are looking for them:
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How to Build A Ground-level Deck?
What Are All The Differences Between Decks And Patios?
How Long Does Composite Decking Last?
How to Build an Outdoor Multi-Level Deck?
