How to Build a Courtyard Deck

From Australian Handyman Magazine

The elevated, U-shaped structure of this home left an unusable patch of land between the wings containing the main family living space and the children’s playroom. The new courtyard deck not only links the wings, but also creates a shaded and private outdoor room, to be enjoyed by family and friends.

Download How to Build a Courtyard Deck PDF

Check before you build
Ask your local council about relevant regulations. Detailed plans, as well as development and building approvals, may be required. Draw a plan of the deck, showing all dimensions, including heights above ground level and footing locations. Check before you start to ensure that your post sizes, bearer and joist spans meet regulations. See Australian Standards AS1720 and AS1684.

Deck
The decking selected for this job is a relatively new product called ‘I-Deck’. It features extra-wide, 135mm boards, fastened with a hidden clip system. This clean, modern clip system means there are no surface fixings required and deck-board spacing is evenly controlled. I-Deck is cut and machined from sustainable hardwood and is available in cream, red and brown colourings. We chose Ironbark for our courtyard deck, for its durability and warm red/brown tones. For more information or supply, contact Hardwoods Australia www.hardwoodsaustralia.com.au

I-Deck boards are machined with a hidden groove down each side. These grooves are designed to accommodate a clip that, in turn, holds the board in place (Diagram 6). To lay I-Deck, the first board must be screwed along its outer edge. The screw holes can be hidden with timber plugs. The small plastic clips then push into the groove on the opposite side of the board, directly above the joists. Tap lightly with a rubber mallet, to ensure the clips are bedded in correctly. The clips are then secured to the top of the treated pine joists, using 65mm x 10g galvanized screws. Use 50mm x 8g galvanized screws when fixing hardwood, and use stainless steel screws if you live close to the ocean. The grooves on either side of the decking board are shaped differently, and the clips are one-directional. This means that once the first board is laid, all the others must run the same way. The boards and clips are designed this way so that the screw heads will be covered by the next board. As the joins are bevelled, the gaps look invisible from directly above.

STEP 1

The U-shape of the house allowed the deck to be supported on three sides by the existing structure, thus minimising the need for support posts. The elevated deck also covered an existing, but obsolete, walkway and created the perfect hiding place for a 5,000-litre water tank. (Diagram 1)
TIP: If you’re a novice at small bricklaying jobs, make a brick gauge to guide the level of each course. Transfer the mortar joint marks from a quality brick wall onto your brick gauge and you’re set to spread some mortar. Bed the bricks in place to match the gauge.

STEP 2

The height of the deck was aligned with the floor level of the house. We attached stringlines, at bearer height and at 1200mm centres, between the wings, and then spanned the space. As the stone water feature weighs in at over a tonne, we planned to position an extra bearer underneath it to ensure that it was well supported. We set an extra stringline to mark this bearer position. After working out the positions of the timber posts and brick piers, we marked their locations on the stringlines. We then dropped a plumb-line to the ground at these marks, to determine the position of the footings. Using a posthole shovel, we dug 400mm-deep holes for the blob footings and then filled them with concrete.

STEP 3

The varied nature of the site meant a range of bearer supports were used. The height of each support was determined by measuring to the ground from the stringlines, and the base of each mounted into a galvanized post support, dynabolted to the footings. The first bearer was supported on 90 x 90mm treated pine posts, bolted to the side of existing piers up against the house. The two central bearers were also supported by 90 x 90mm treated pine posts. The outer bearer, which spanned an existing brick and concrete walkway, was supported on three brick piers, to carry the weight of the water feature. We spanned a straightedge topped with a spirit level from pier to pier, to check for level.

STEP 4

We cut 190 x 40mm housings on the top of each support post to carry the bearer (Diagram 3). We then drilled 10mm clearance holes and bolted them together. We created additional support at the ends of the bearers by extending them under the house, and securing them to the side of the sub-floor bearers with steel brackets. We topped the brick piers with damp course and ant capping, then positioned the outer bearer on top. A ledger was fixed to the boundary wall to carry the ends of the joists and allow the deck to continue as a walkway to the backyard. When all the bearers were in place, we checked for level and then used a taut stringline to mark the joist positions on top of the bearers.

STEP 5

We positioned the 140 x 45mm treated pine joists perpendicular to the bearers, and spaced at 450mm centres. Each joist was fixed to the bearer below, using a single, galvanized, triplegrip tie bracket at each crossover point. These brackets are designed to connect timbers positioned a 90º angle to each other. (Diagram 4) Triple-grips come in both left and right configurations and nail to the side of the joist, and the top and side of the bearer. For this deck, the brackets were alternated from left to right, at each intersection along the joist, to help keep the joist upright and plumb. The ends of the joists extended beyond the last bearer to a ledger connected to the brick boundary wall. These overhanging sections were further supported with the aid of small timber stands. Galvanized angle brackets were bolted to the concrete, and to the inside of the joists, to keep them firmly locked in place.

STEP 6

We created a level change in the deck sub-frame, to form an entry step and a step down to the water feature trough. We achieved this easily by lowering some sections of the joists so that they ran between the bearers (like noggings in a wall), rather than over them. As the joists are 140mm-deep, this effectively created a 140mm step down. We used joist hangers to support the sections of joists between the bearers (Diagram 5). If installed correctly and with the specified fasteners, joist hangers are incredibly strong. All treated pine framing timbers, and Pryda brackets and ties, are available from Bunnings Warehouse. Cut the 9mm marine ply to fit the base of the stepdown area, and then fix the ply directly to the bearers and joists, using construction adhesive and stainless steel screws. Lay the rubber pond liner in the reservoir and fold the corners neatly, before positioning the galvanized trim.