Wooden Decking in Portland

• Have a step tread width of 900mm – if you don’t want them that wide, they should be no less than 760mm
• Add a central step riser to stairs wider than 900mm to prevent them buckling
• Add a step depth (the vertical distance between each step) of between 150 and 180mm if building your own riser, so the steps are at a comfortable depth

• Step treads (the actual step themselves)
• Step risers
• Coach screws
• Deck screws
• Saw
• Drill

1. Make sure the ground where you want to put your steps is level and firm. If it’s not, consider laying concrete or paving slabs to provide a secure surface for your steps to sit so they don’t sink.
2. Grab some joist off-cuts and cut them to the same width as your step treads. Attach them to the step risers at the top and bottom using countersunk coach screws.
3. Place the steps against the sub-frame of the deck; if you’ve put slabs down for support, make sure the steps sit in the middle of them. The longest edge of the stair riser should be on the slabs, and the short edge against the deck. Drill pilot holes through the step and sub-frame joist, then screw the step to the sub-frame with more coach screws.
4. After drilling pilot holes, screw the treads into the risers at each end with deck screws.
5. If you don’t want gaps between each stair, you can add joist off-cuts or deck boards. Measure the height and depth of the gap, then screw the off-cut or board into the step riser with two screws at each end.

• Decking joists
• Coach screws
• Coach bolts
• Combi drill
• Socket set
• A saw suitable for your project and the thickness of the timber
• Pencil
• Decking preservative
• Sandpaper or sander

1. Measure your deck frame and cut to size if necessary.
2. Make 2 pencil marks on each end of the frame’s 2 outer joists to mark where the coach screws will go. They need to align with the centre of the adjoining outer joist. Then, use a flat wood drill bit to drill recesses into each mark. Make them the same depth of the screws that your using’s head and wide enough for a ratchet or socket to tighten them.
3. Using a thinner drill bit, line up the outer joists and drill a pilot hole through the middle of the recess. These pilot holes act as a guide for the screws and stops them from splitting the wood.
4. Fit the coach screws with either a drill driver or socket and ratchet.
5. Repeat the process for the inner joists once you’ve assembled the outer frame.

If your deck isn’t going to be flat to the ground, it’s a good idea to have some kind of balustrade to avoid any tripping. If the gap between the deck and the ground is less than 600mm, use a 900mm balustrade. If it’s higher than 600mm, the balustrade should be 1100mm tall.

1. Calculate the surface area for your decking Multiply the length (L) of your decking area by the width (W): L x W = Decking Surface Area (DSA) in m² 10 x 6 = 60m²
2. Work out the coverage of your deck boards Add your deck board width (DBW) to the expansion gap length (EGL), then add the deck board length (DBL) to the expansion gap width (EGW). Then multiply these numbers. (DBW + EGL) x (DBL + EGW) = Single Board Coverage (SBC) 0.144m + 0.005m = 0.149m 2.4m + 0.003m = 2.403m 0.149 x 2.403 = 0.358m²
3. Calculate the number of deck boards you need Multiply the SBC by 1.1 to allow for 10% wastage. Then, divide the DSA by the SBC. DSA / SCB x 1.1 = Total number of boards required 60m² / 0.358m² x 1.1 = 184.36 boards – so round up to 185 so you’re not left short.