How Much Does It Cost to Build a Composite Deck?

How Much Does It Cost to Build a Composite Deck?

A composite deck, like a lot of other home improvement components, makes a home more valuable. It also transforms unused spaces of your property into useful ones. 

However, building the right composite deck isn’t as easy as you think. To build a safe and durable composite wood, individuals should use a suitable decking board. But, this board itself only accounts for 1/3 of the total costs you’ll spend on your composite deck.

Often, some people opt for low-quality wood, which is a bit cheaper upfront. However, with time, you’ll end up paying more on maintenance and in some cases, even replacements as the wood can easily rot or get infested by termites.

How much money you use building your composite deck depends on your deck size, how complicated its design is, the quality of materials you use, and if you’ll incorporate special features like fire-resistant boards. 

A Breakdown of the Cost of Building a Composite Deck

Here are some estimates per SQM of building a composite deck


  • 50SQM- $5300-$7200
  • 40SQM- $5000-$7000
  • 30SQM- $4000-$6800
  • 20SQM $3800-$5300
  • 10SQM $3600-$5500


Whether you are replacing rotten timber or low-quality wood with composite products of high quality, you should understand how much you’ll spend on each product and process. Here’s a breakdown of how we came up with these average costs:



It’s where you are going to spend much of your money. It’ll cost 20-40% of the overall budget to install the deck. If you’re going to hire a professional make sure that they are well trained to handle the job. Also, check for license and certification. Additionally, you can take the DIY route, which is more affordable, but you’ll invest a lot of effort and time. However, with some research, you can perfectly install a composite deck of your dream.

Fixings and Accessories

These are important as they contribute to the design of your composite deck. If it’s well designed, the installation would be easier, which saves time and money. Fixings and accessories cost $5-$12/SQM, which is approximately 5% of the total cost.



These take up 20% of your total budget. You can choose boards from softwood, hardwood, or composite decking. But, note that each option features different pricing, from cheap to extremely expensive.


The Subframe

It takes 30% of your total budget. Although this may seem much, remember that you need to lay a sturdy firm foundation for your deck. Therefore, you’ll use much of your money investing in support beams, joists, and posts that have a sound structure and match your board’s requirements. You can choose a subframe made of steel, hardwood, or softwood, depending on what you prefer.


Composite Deck Estimates

You need to consider several things before you begin comparing quotes and prices. These are;


The Size of the Boards– the industry-standard board sizes measure 137mm wide. However, some companies may offer bigger sizes like 159mm wide, which will be more expensive, of course. Plus, there are boards measuring 5.4m and others 5.8m. Note that while the bigger ones may seem a bit costly, you’ll use fewer boards to build a composite deck.

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The Thickness of the Boards- thicker boards are more durable than lighter ones. But, they are also more costly. Rather than opting for 24mm thickness boards, choose the ones of 25mm thickness, for durability purposes.

Fixings- most installers use a hidden fastening system when building a composite decking. This system fastens the installation process by 60% compared to wooden boards. You can save money on fixings by purchasing your boards from companies that offer them free of charge.

Maintenance– when calculating the total cost of your deck, think about its life cycle. Wood decking can rot and split, which means it’ll need regular repairs and replacements to preserve the structural integrity and appearance of your wood.

Design– complex designs are costlier as they have several levels, built-in grills, elaborate railings, etc. Also, if you’ll build your deck on a second story, it will cost more.

Tips and Options to Cut Down on Costs

If you’re budget-conscious, there are some steps you can take to reduce how much you spend. These include:


  • Building your composite deck on your own.
  • Hiring a composite deck installer during the off-peak season for affordable installation charges. Note that deck prices are mostly higher during the summer since the materials and contractors are usually in high demand. So try building yours in spring or fall. 
  • Instead of curved and complicated designs, go with straight decking as it is much cheaper.
  • Take advantage of efficient features like outdoor storage to make more use out of your space.
  • Incorporate creative designs that don’t up the cost. For instance, you can use a mix and match the color scheme.
  • Get multiple quotes from different builders and compare the price in terms of quality.


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