How to Build a Deck Box with Cedar Fencing Boards

A cedar deck box is a useful way to store cushions, pool equipment, gardening tools, children’s toys and outdoor entertaining supplies. Cedar fencing boards are light, attractive and relatively easy to cut, making them a practical material for a weekend DIY project. The finished box can sit beside a deck, under a verandah or near a swimming pool.

This project uses a simple timber frame covered with cedar boards. The frame gives the box strength, while the cedar creates the visible walls and lid. A separate hinged top, ventilation gaps and a raised base help the storage chest cope with Australia’s sun, rain and changing humidity.

The dimensions can be adjusted to suit your available space. A box measuring about 1200mm long, 500mm deep and 600mm high is large enough for several outdoor cushions without becoming difficult to move. Check the size of your deck, side path or balcony before buying materials.

Cedar is sold through many Australian timber merchants, hardware stores and fencing suppliers, although stock and board profiles vary between states. Western red cedar may cost more than treated pine, while locally available fencing boards can differ in width, thickness and surface finish. Measure the actual boards before finalising your cutting list.

Choose the size and materials

Start by deciding what the deck storage box needs to hold. Cushions need a broad, shallow container, while pool toys and garden equipment may suit a taller design. Keep frequently used items within easy reach and avoid making the box so large that the lid becomes heavy or awkward to lift.

For a medium-sized box, gather enough cedar fencing boards for the front, back, sides and lid. You will also need treated pine or durable hardwood for the internal frame, plus exterior-grade screws, two or three heavy-duty hinges, a lid stay and a latch. Stainless steel or hot-dipped galvanised fixings are preferable because ordinary steel screws can stain cedar and corrode in damp coastal locations such as Newcastle, Wollongong or the Gold Coast.

Allow for a base that keeps stored items away from the ground. A set of treated battens, plastic feet or outdoor furniture glides can raise the box by 50mm to 100mm. Add a breathable waterproof storage liner or internal tub if the contents must remain particularly dry. A cedar box is weather resistant, but it should not be treated as completely waterproof.

Measure the board thickness before choosing the frame dimensions. Common fencing boards may be around 12mm to 19mm thick, but local products are not always consistent. A box with a 900mm internal length, for example, will need longer external rails once the cedar cladding and frame thickness are included.

Prepare the cedar boards and base

Sort the boards before cutting. Set aside pieces with large knots, splits or severe cupping for short sections, and use the straightest boards on the front and lid. Cedar is soft, so support each board well while cutting to prevent vibration and ragged edges. A sharp combination blade on a circular saw will give cleaner results.

Cut the boards for the front and back first, then cut the side boards to fit between or over the end rails according to your design. Sand the cut ends with 120-grit abrasive, followed by a lighter pass around the visible edges. Slightly rounding the corners reduces splintering and gives the box a more finished appearance.

Create the base from exterior-rated plywood, spaced timber slats or cedar boards fixed across two or more support rails. A slatted base improves airflow and lets minor condensation escape. If you use plywood, seal every edge carefully and keep it raised above the paving or decking surface.

Before assembly, lay out the boards on a flat surface and check the grain direction. Leave a small expansion gap between vertical boards, generally 2mm to 4mm depending on the board width and the manufacturer’s guidance. Timber expands and contracts with moisture, so tightly butted boards can buckle after a wet season.

Build the supporting frame

Construct two rectangular end frames using treated pine or hardwood rails. For the sample box, each end frame can be about 500mm wide and 600mm high, with the exact size adjusted for board thickness. Screw the rails together on a level surface, pre-drilling near the ends to reduce splitting.

Join the end frames with horizontal rails at the top, bottom and corners. Check the box for square by measuring both diagonals; they should be equal or very close. Clamp the rails while driving screws, and use a carpenter’s square at each joint. A square frame makes the cedar cladding and hinged lid much easier to install.

Add an intermediate support rail along the front and back if the box is longer than about 900mm. This stops the boards from flexing and gives you another fixing point. Install a central base support as well, particularly if the box will hold dense items such as potting mix, paving tools or wet pool gear.

Fix the base to the lower frame rails after checking the structure again. If the box will sit on a tiled patio in Brisbane or on a timber deck in Perth, fit rubber feet or plastic packers underneath. These small spacers reduce trapped moisture and prevent the lower timber from sitting in puddles after heavy rain.

Attach the walls and hinged lid

Begin cladding on the least visible side so you can establish your preferred fixing method. Hold each cedar board level, drill pilot holes and use two screws at every frame rail. Keep the screw heads flush with the surface rather than countersinking deeply, which can leave pockets where water collects.

Work around the box, checking the top edge as you go. A temporary spacer cut from scrap timber will help maintain even gaps. For a more contemporary look, install the boards vertically; for a traditional outdoor chest, horizontal boards create a familiar fence-panel appearance. Either direction works as long as the frame supports the boards adequately.

Build the lid as a shallow rectangular frame with one or two cross supports. Cover it with cedar boards, allowing the boards to overhang the walls by about 10mm to 20mm on each side. A slight overhang helps direct rain away from the joints. Keep the lid light enough to lift comfortably, especially if the box will be used by children or older household members.

Fit the hinges along the back rail and test the lid before installing the latch. A gas strut, folding lid stay or purpose-made soft-close support prevents the lid from falling unexpectedly. Do not rely on friction hinges alone if the box is in a windy position. In exposed areas such as Adelaide’s suburbs or the Victorian coast, a sudden gust can put considerable strain on the hinge screws.

Protect timber from Australian weather

Cedar can be left unfinished to weather naturally to a silver-grey colour, but an exterior timber oil will help retain some of its original colour. Choose a product labelled for outdoor use and follow the manufacturer’s preparation and re-coating instructions. Test the finish on an offcut first, as cedar can absorb oil unevenly and may become significantly darker.

Seal the end grain, especially at the bottom of the boards and around cut-outs. End grain absorbs water faster than the broad face of the timber. A quality exterior sealer or compatible oil can reduce checking and moisture uptake. Avoid applying a film-forming coating to damp wood, as peeling may follow when the timber moves.

Use a breathable approach to waterproofing. The lid should shed rain, while the walls should have enough airflow to dry after wet weather. Drill several small ventilation holes beneath the side overhangs or near the upper rear wall, then cover them internally with fine stainless mesh. Keep the holes high enough to reduce the chance of driven rain entering.

Consider the box’s position throughout the year. Full western sun can heat a cedar storage chest intensely during summer, especially in western Sydney or inland parts of New South Wales. A partly shaded spot under a pergola or verandah usually extends the life of the finish and protects cushions from heat. Leave a small gap between the box and a masonry wall so air can circulate.

Add practical storage and safety features

Line the inside with a removable outdoor fabric liner, plastic storage tubs or a raised insert if you plan to store cushions. Avoid placing wet towels, damp pool noodles or freshly watered gardening items directly inside a closed box. Even with ventilation, trapped moisture can encourage mildew and create a musty smell.

A latch can keep the lid secure, but avoid creating an airtight container. If the box is accessible to young children, use a lid support that prevents sudden closure and avoid a locking mechanism that could trap someone inside. Sand every accessible edge thoroughly, including the underside of the lid and the corners near the hinges.

Cedar fencing boards are suitable for light to moderate storage, not for sitting or standing unless the frame has been specifically reinforced. If the box will double as a bench, install a stronger hardwood frame, add additional cross rails and design the lid for the expected load. Check the hinges and fasteners regularly because repeated sitting can loosen joints.

Inspect the box at the start of each wet season. Tighten loose screws, clean leaves from the lid gap and check whether the feet remain stable. Look for soft timber at the base, rust around fixings and gaps that have closed as the wood has moved. Re-oil cedar when the surface looks dry or begins to absorb water unevenly.

A box near a swimming pool needs extra attention. Chlorinated water, salt spray and sunscreen residue can affect finishes and metal hardware. Rinse the exterior occasionally with clean water, avoid harsh pressure washing and select stainless fixings where possible. Keeping the chest several steps away from the pool edge also reduces splashing and improves access around the equipment.

A cedar deck box can be assembled with basic woodworking tools: a tape measure, square, drill, circular saw, clamps, sandpaper and a level. Work on a stable surface, wear eye and hearing protection when cutting, and use a dust mask while sanding. Treat offcuts and sawdust responsibly, particularly if the timber has been coated or chemically treated.

Before filling the box, place it in its final position and confirm that the lid opens fully. Make sure it does not obstruct a stairway, pool access route, outdoor tap or barbecue. Once positioned, label tubs or use dividers so cushions, toys and garden accessories remain easy to find.

Gather straight cedar boards, weather-resistant hardware and a suitable frame timber, then mark out the box carefully before making the first cut. A patient build, raised base and regular maintenance will produce useful outdoor storage that suits an Australian deck for years.