How To Lay A Deck: An Australian Guide

Building a deck in your garden can be a transformative project, giving you an extra ‘room’ outdoors. It can boost the aesthetic appeal of your home and provide a new space for outdoor entertaining or relaxation. This article will guide you on how to lay a deck, explicitly focusing on decking in Australian conditions.

Why Choose Decking in Your Garden

Decking can turn a bare, unused garden into a beautiful, functional space. It’s perfect for Australian homes, where the climate lends itself to outdoor living for much of the year. Timber decking offers an organic, natural aesthetic that blends seamlessly with garden environments.

There’s also the added advantage of enhancing the value of your property. Decking creates an attractive visual feature, a bonus for potential buyers if you plan on selling your home.

Benefits of Composite Decking

When it comes to decking materials, composite decking is gaining popularity. Solid composite deck boards are made from a mixture of wood and plastic, which gives them the appearance of timber but with added durability. Composite decks are resistant to rot, insects, and UV damage, making them a robust, low-maintenance option for outdoor space.

How to Lay A Deck: A Step-by-Step Guide


  1. Mark Your Deck Area: Determine the size and position of your deck. You can use string lines or spray paint to mark out the area. Make sure it’s square by checking the diagonals are equal.
  2. Secure the Outer Joists: Secure your outer joists after marking the site. If you’re building a raised deck, you’ll need posts to support the beams. Make sure everything is level and straight using a spirit level and straightedge.
  3. Install the Inner Joists: Next, add the inner joists. Spacing will depend on your deck board’s width and the decking materials. A gap of about 400mm between posts is appropriate for most deck boards.

Laying Decking Boards

This is where the process of laying deck boards comes into play. Here’s a guide on how to apply decking boards in Australia:

  1. Start at One End: Position your first board flush with the edge of the deck and secure it to the joists with screws. Make sure to drill pilot holes to prevent splitting the wood. Use a chalk line or straightedge to ensure the board is straight.
  2. Spacing the Boards: Composite decking boards require an expansion gap for heat and moisture fluctuation. Usually, a 3mm gap between boards and a 6mm expansion gap at the ends of the deck boards is appropriate.
  3. Cutting Deck Boards: Some boards might need trimming to fit. Mark the cut line with a chalk line and cut with a circular saw or handsaw. Always ensure a straight cut.
  4. Securing the Boards: For a clean look, consider using hidden fasteners that fit into grooves on the sides of the deck boards. Alternatively, you can screw directly into the board, remembering to pre-drill the holes.
  5. Checking for Straightness: Check that your deck boards run straight every few rows. If they’re drifting, adjust as necessary.

Finishing the Deck

Finish the edges with cut-offs or fascia boards once all the deck boards are laid and secured. Sealing the cut ends of the panels is recommended to prevent moisture from penetrating the wood.

Learning how to lay a deck can be a rewarding DIY project. It enhances your living space and adds value to your home. When applying your decking, always remember to take your time, especially when securing the joists and laying the deck boards. If in doubt, seek professional help or advice.

Remember, decking in your garden is about more than just the practicality of having extra space. It’s about creating an area for family barbecues, a place for your children to play, or a tranquil spot to read a book on a sunny day. So, get creative with your garden ideas, and make the most of your outdoor space with a beautifully laid deck.

A Guide to Choosing Your Decking Materials

When considering how to lay a deck, one of the critical decisions you’ll need to make is the decking material. Different materials come with their own sets of advantages and aesthetic appeals.

Timber Decking

Timber is a classic choice for decking due to its natural beauty and versatility. In Australia, popular timber choices include Jarrah, Spotted Gum, and Merbau, all known for their durability and attractiveness.

Timber does require regular maintenance to protect it from the elements. However, a timber deck can last for many years with proper care.

Composite Decking

Composite decking, as mentioned earlier, is an excellent alternative to timber. It’s particularly beneficial for those who want the look of wood without maintenance.

The best way to lay decking boards made of composite material is to use hidden fasteners for a seamless finish. Solid composite deck boards also offer durability and resistance to fading, staining, and mould.

Ensuring a Professional Finish

Laying decking boards with precision and care is vital to achieving a professional-looking finish. Here are some additional tips to help you along the way.

Using Quality Screws

Invest in high-quality decking screws. They will hold the deck boards securely and resist rust. Some screws are designed for composite decking, offering a flush finish.

Keeping Deck Boards Straight

The straightness of your decking boards is crucial for a professional finish. Use a string line or a long straight edge regularly to check your progress and adjust as needed.

Finishing Touches

Consider the finishing touches that will enhance the usability and appearance of your deck. Adding railings or balustrades can provide safety and a visual element. Built-in seating or planters can transform your patio into an inviting outdoor space.

Common Mistakes to Avoid When Laying A Deck

Like any DIY project, there are common mistakes that you should avoid when learning how to lay a deck. Here are a few to keep in mind:

Incorrect Joist Spacing

One of the crucial aspects of laying a deck is ensuring that the joists are correctly spaced. This guarantees that the deck can adequately support the weight placed upon it. The deck boards could bow or crack if the posts are too far apart. Always check the manufacturer’s guidelines for the appropriate spacing for your chosen decking material.

Ignoring Expansion Gaps

Especially important when installing solid composite deck boards, expansion gaps are vital. They accommodate the natural expansion and contraction of the decking material due to temperature changes. If you ignore these gaps, your deck could warp or buckle.

Not Sealing Cut Ends

Cutting a deck board exposes the raw timber, which can absorb moisture and lead to rot. Sealing any cut ends with an appropriate product is essential to prevent moisture penetration.

Poor Planning

Planning is crucial for a successful deck installation. Ensure you have all the materials and tools needed before you start. Consider the size and shape of your deck, and think about how it will be used. The more planning you do upfront, the smoother the installation process.

Maintaining Your Deck

Once you’ve learned how to lay decking and have finished the installation, it’s important to remember that decks require maintenance to keep them looking their best and to prolong their lifespan.

Regular Cleaning

Regular cleaning is crucial, especially for timber decks that can gather dirt, grime, and algae. A pressure washer can help make this task more accessible, but be careful not to damage the wood. For composite decks, a simple wipe-down with a cloth should suffice.

Re-sealing and Staining

For timber decks, re-sealing and staining every few years is advisable. This process helps to restore the wood’s natural colour and protects it from UV damage, moisture, and insects.

Checking for Damage

Regularly check your deck for signs of damage. This includes splitting or warping boards, loose screws or nails, and any signs of rot or insect damage in timber decks.

Your New DIY Skill: Deck Laying

Mastering the skill of laying a deck can bring you outstanding achievement. Not only have you created a new, enjoyable space in your home, but you’ve also added value to your property. Whether you’ve chosen a natural timber deck or a low-maintenance composite deck, knowing how to lay a patio will be valuable to your DIY skill set. Remember to enjoy the process and look forward to the countless memories you’ll create on your new deck.


In DIY, learning how to lay a deck is a worthwhile skill that pays off in the form of enhanced outdoor living space. This guide has covered the process from preparing the ground, securing the joists, and laying decking boards to the final finishing touches.

If you’re considering decking in your garden, take your time to plan, prepare, and select the suitable materials for your needs. With a little effort and attention to detail, you’ll have a beautiful deck to enjoy for years. Whether installing timber decking or opting for composite materials, the journey to a finished deck is an exciting process filled with potential.

Ultimately, a well-laid deck provides the perfect stage for countless memories, from casual family barbecues to tranquil afternoons in the sun. So go ahead and take that first step towards laying your deck, and look forward to the benefits and enjoyment this outdoor feature will bring.