How Much Does It Cost to Build a 20x20 Deck? A Complete Guide

Building a deck is one of the best ways to expand your outdoor living space, add value to your home, and create a welcoming place for gatherings, barbecues, or just enjoying the sunshine. Among the most popular deck sizes, a 20x20 deck (400 square feet) stands out as a versatile choice that provides plenty of room for furniture, entertaining, and relaxation.

But the question most homeowners ask first is: How much would a 20x20 deck cost to build?
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The answer depends on a range of factors, from the material you choose to the complexity of the design. On average, you can expect to pay anywhere from $16,000 to $24,000 or more. Let’s break down the details so you know what goes into that price tag—and how to plan for your perfect deck.

Average Cost of a 20x20 Deck

A 20x20 deck covers 400 square feet, making it a significant addition to your home. Based on national averages:

• Low End (Pressure-Treated Wood): Around $16,000–$18,000
• Mid-Range (Premium Woods like Redwood or Cedar): Around $18,000–$22,000
• High End (Composite or Vinyl Materials): Around $22,000–$24,000+
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This cost range includes both materials and labor but can shift depending on where you live, the expertise of the contractor, and any design extras you choose.

Major Cost Factors to Consider

Several elements influence the final price of your deck project. Understanding these will help you budget realistically and make informed choices.

1. Materials
The largest factor in deck cost is the type of material you choose.

• Pressure-Treated Wood:
  This is the most budget-friendly option, costing between $25 to $50 per square foot. While affordable upfront, it requires regular maintenance, including sealing and staining every year. Without proper upkeep, it can warp or splinter over time.
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• Premium Natural Wood:
  Options like redwood or cedar are more attractive and naturally resistant to pests and rot. Expect costs of $4 to $20 per square foot for materials alone. They look beautiful but will still need some maintenance to preserve their color and longevity.
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• Composite or Vinyl:
  These materials are designed for durability and low maintenance. With composite decking, you won’t need to worry about sanding, staining, or warping. While it can cost $5 to $20 per square foot just for materials, it often saves homeowners money in the long run because of reduced maintenance
  
  

2. Labor Costs

Labor is a significant portion of the total cost, and it varies depending on your location and the design’s complexity. A simple, straightforward deck will cost less in labor than one with intricate railings, multiple levels, or built-in features.

Skilled labor ensures your deck is safe, durable, and compliant with building codes, making it one of the most important investments in your project.

3. Deck Size

The bigger the deck, the more materials and labor are needed. At 400 square feet, a 20x20 deck is already on the larger side, making it a substantial investment. Adding even a few extra feet can increase costs significantly, so it’s wise to plan carefully.
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4. Design Complexity

If you’re dreaming of a simple square deck, your costs will be lower. However, if you want:
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• Multiple levels
  
  
• Custom railings
  
  
• Built-in seating
  
  
• Planter boxes
  
  
• Lighting
  
  
• A pergola or shade cover

Material Cost Comparison (Excluding Labor)

Here’s a quick look at material costs per square foot for a 20x20 deck:

• Pressure-Treated Pine: $25 – $50 per sq. ft.
  
  
• Premium Natural Wood (Cedar, Redwood): $4 – $20 per sq. ft.
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• Composite Wood: $5 – $20 per sq. ft.
  

While this shows material prices, remember that installation costs can double or triple the total once labor and additional features are factored in.

Choosing the Right Material for Your Deck

When deciding on a deck material, think about more than just upfront cost. Consider how much time, effort, and money you want to spend on maintenance over the years.
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• Best for Budget: Pressure-treated wood is ideal if you want a deck at the lowest upfront cost.
  
  
• Best for Natural Beauty: Redwood or cedar provides stunning aesthetics and is naturally resistant to decay.
  
  
• Best for Durability: Composite or vinyl decking costs more upfront but saves money long-term by eliminating the need for staining, sanding, or frequent repairs.

How to Get the Most Accurate Estimate

Because deck-building costs can vary widely depending on location and contractor, here’s a three-step process to help you get the most accurate estimate for your project:
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1. Choose Your Material
   Decide whether you want pressure-treated wood, a premium hardwood, or composite/vinyl. Each comes with its own advantages in terms of aesthetics, longevity, and maintenance.
   
   
2. Research Local Prices
   Materials and labor costs differ by region. Contacting local deck builders gives you a more realistic picture of what to expect.
   
   
3. Consider Additional Features
   Think about upgrades like built-in benches, railing designs, under-deck storage, or a pergola. Adding these elements during the initial build is often more cost-effective than adding them later.

Why a 20x20 Deck is Worth the Investment

While the price may feel steep, a 20x20 deck can be one of the best home investments you make. Here’s why:

• Increased Home Value: A well-built deck can add substantial resale value to your home.
  
  
• More Living Space: It’s like adding another room—perfect for dining, entertaining, or relaxing.
  
  
• Lifestyle Benefits: Imagine summer evenings outside with friends, family barbecues, or a peaceful morning coffee outdoors.
  
  
• Durability: With the right material choice and professional installation, your deck can last decades

DIY vs. Professional Installation

You might be tempted to save money by attempting a DIY build. However, for a structure as large and important as a deck, hiring professionals is usually the smarter choice.

• DIY Pros: Lower upfront labor costs.
  
  
• DIY Cons: Requires specialized tools, knowledge of building codes, and significant time. Mistakes can lead to costly repairs—or even safety hazards.
  
  

With a professional deck builder, you get:

• Expertise and efficiency
  
  
• Code compliance
  
  
• Warranty or guarantees
  
  
• A safe, long-lasting structure
  
  

For a 20x20 deck, professional installation is almost always the better option.

Planning Your Deck Budget

When budgeting for your deck, here’s a helpful framework:
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• Materials (40–50%): Choose based on your lifestyle and how much maintenance you’re willing to do.
  
  
• Labor (40–50%): Invest in skilled professionals to ensure safety and longevity.
  
  
• Extras (10–20%): Leave room in your budget for railings, lighting, or unexpected costs.
  
  

It’s also smart to set aside a contingency of 10–15% for unforeseen issues, such as soil preparation or permit fees.

Final Thoughts

A 20x20 deck costs between $16,000 and $24,000 or more, depending on the materials you choose, labor rates in your area, and the complexity of the design. Pressure-treated wood offers an affordable entry point, premium hardwoods provide natural beauty, and composite or vinyl offer long-term durability with minimal maintenance.
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Building a deck is a major investment in your home and lifestyle, so take the time to choose wisely and work with experienced professionals. With the right planning, your new deck will become a lasting extension of your home where memories are made for years to come.

Ready to Build Your 20x20 Deck?

If you’re ready to turn your backyard into the ultimate outdoor living space, Ogden Decks is here to help. Our team specializes in building high-quality decks tailored to your vision, lifestyle, and budget. Whether you want the affordability of pressure-treated wood, the elegance of premium hardwoods, or the low-maintenance durability of composite materials, we’ll guide you through every step of the process.
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Call Ogden Decks today at +1 (801) 528-9807 to schedule a consultation and get your personalized deck estimate. Let’s build the deck you’ve been dreaming of!