How to make D.I.Y. modular outdoor furniture

To make this project easier, you can have most of the timber pre-cut at your local Bunnings*. Then you'll only need to cut the legs, chair and back supports yourself. Here's our cut list for this project:

Cut the 90mm x 45mm hardwood pine to:

• 450mm x 12
• 575mm x 6
• 440mm x 6
• 580mm x 4

Cut the 65mm x 19mm Tasmanian oak to:

• 575mm x 6
• 420mm x 6

Cut the 86mm x 19mm Blackbutt timber to:

• 529mm x 12
• 620mm x 8

*Not available at all Bunnings stores.

Before we start building the outdoor setting, it's a good idea to lay out the frame to make sure that it fits together. The edges should all be square and flush before you start.

Lay out the 65 x 19mm Tasmanian oak sub-frame, with the two 575mm lengths for the sides and the two 420mm lengths for the back and front. To make the sub-frame, pre-drill a clearance hole with the 5mm drill bit, then drill a 3mm pilot hole to ensure the screw has good traction. Glue the edges and then screw into place. Remove excess glue as you go.

The 12 lengths of 90mm x 45mm x 450mm hardwood is for the legs of the two chairs and ottoman. Measure up 350mm on each leg and mark this point. From the opposite side of the 350mm at the base of the leg, measure in 50mm and mark this position. Draw a line between the 50mm mark and the 350mm mark. This'll be the angle for the tapered leg. 

Clamp four of the legs together at a time, then clamp a timber offcut to the front of each batch to hold them in place while sanding. Use the belt sander with 80-grit sandpaper and then 120-grit to smooth out the legs. By clamping the legs together, you'll limit the variation in leg shape. You should also sand all of the other timber before you put everything together.

When you're assembling the framework remember that the tapered sides on the front and back legs face each other. First, select and mark out the position for two evenly spaced pilot holes on each leg face. Use a 5mm bit to pre-drill and countersink as a clearance hole. Then drill clearance holes right through the countersink hole with a 6.5mm bit for the batten screw. You'll need to fix the leg into the sides too. So in the centre of these two holes, and on the opposite side of the taper, use the 5mm pre-drill and countersink bit to pre-drill a clearance hole for the screws. Then drill clearance holes right through the countersink hole with a 6.5mm bit for the batten screw. Once you've pre-drilled the clearance holes, use the 5mm bit to pre-drill pilot holes. Position the sub-frame and then assemble the legs, back, front and sides around it. Glue and then fix with two 85mm batten screws on the face of the leg.

So the timber sides don't split, and before fixing the legs into place with the larger 125mm batten screw, pre-drill, right through the previous countersink hole, using a 6.5 mm bit. Once you have a mark on the timber, use a 5mm bit to pre-drill the pilot hole. Glue and fix a 125mm batten screw into the face of the leg and into the outer frame. Repeat this screwing and drilling process for the other chair and the ottoman.

The blackbutt timber slats should sit flush at the top of the chair. So you'll need to gently tap down the sub-frame so they can fit. Use a slat the same size as the blackbutt as a spacer to help you. When it's in position, fix the sub-frame into place by drilling a 6.5mm clearance hole and then a 5mm pilot hole, before screwing into place with 50mm batten screws.

Measure how long you need the blackbutt slats to be, ours measured 529mm. The slats are fitted so that they run parallel to the tapered legs at the front and back. Use the drop saw to cut the all the slats to length. You'll need six for each seat, and then repeat the process for the ottoman.

It's a good idea to give the slats a rounded edge with 120-grit sandpaper before you attach them. Lay the slats out first before fixing them into place. Fit two hard up against the front and back of the chair with the rest evenly spaced using an 11mm spacer. Then secure into place with a nail gun.

The chair back supports will be cut on a slight angle for more comfort. To do this, measure 43mm in from the top edge of the backrest and 400mm down from the top edge. Join these points with a pencil line. Then clamp the timber to a workbench before cutting with a circular saw.

On the tapered side, make a check-out to fit the back support to the base of the chair. Our check-out measured 25mm in and 90mm up the length of the timber. To make it, cut the 90mm length with the circular saw then finish the cut with a handsaw.

Give the supports a great finish by sanding them. Simply clamp them together and use a belt sander, starting with 80-grit and then move to 120 grit for a smooth finish. Clamping the timber together helps to eliminate variation in the shape. Then give it a sand with a sanding block and sandpaper for a smooth finish.

The screws you use will need to fit through the support and into the chair, without hitting the screws already holding the legs in place. Measure and mark for these accordingly. Pre-drill with a 5mm bit and countersink. Drill a clearance hole with a 6.5mm bit, then position and mark out the pilot hole 5mm bit into the leg. Secure the backrests with 85mm batten screws, making sure they're square.

Measure, mark and cut the four 620mm slats for the back of the chair. Start at the top and work down, using an 11mm spacer, leaving a gap between the last slat and the seat of the chair. Make sure the slats have an equal overhang on both sides. Then glue and nail them off. Remove any excess glue as you go.

To finish your outdoor setting off, putty up any holes. Let it dry and then sand back. Give the setting a coat of exterior varnish to seal the timber and protect it from the weather. Apply as many coats as needed, leaving it to dry between coats.