MAKE SOMETHING THAT STAYS.

The garden bench.

A simple, substantial seat. Built one good joint at a time.

01 / ASSEMBLY STUDIO3D · TO SCALE

The complete benchDrag to rotate · Scroll to zoom

01 / BEFORE THE FIRST CUT

A measured start.

All sizes are actual finished dimensions in millimetres. Measure your timber first; nominal sizes are not interchangeable.

Timber & cut list

Part	Qty	Section	Cut length
A · Seat slat	3	45 × 145	1,200 mm
B · Long apron	2	45 × 145	1,100 mm
C · End apron	2	45 × 145	297 mm
D · Centre support	1	45 × 145	297 mm
E · Leg	4	90 × 90	405 mm

Use straight, dry, exterior-suitable timber, with no splits or loose knots around joints. The diagrams omit small edge roundovers.

THE SHOPPING LIST

Wood. Hardware.
Nothing missing.

Buy sound stock with a little spare length. Hardware must suit both the wood species and its treatment.

Suggested stock lengths

3 × 3,000 mm boards, actual 45 × 145 mm. Board 1: two 1,200 mm slats + one 297 mm end. Board 2: one 1,200 mm slat + one 1,100 mm apron + one 297 mm end. Board 3: one 1,100 mm apron + one 297 mm centre support.
1 × 2,000 mm post, actual 90 × 90 mm. Cut four legs at 405 mm. These layouts leave room for a typical 3 mm saw kerf and end trimming; mark each cut separately.

Hardware & finishing supplies

16 × M8 × 160 mm exterior through-bolts, with 16 compatible locking nuts and 32 large washers. Check the assembled 135 mm timber thickness against usable bolt length and nut engagement before buying. Choose matching corrosion-resistant hardware; keep exposed ends smooth or covered.
18 × 5 × 80 mm exterior wood screws for the seat (buy a pack with spares). The 45 mm seat leaves approximately 35 mm penetration into the supports. No drywall screws.
4 structural framing angles for the centre support: two per end, one on each side. Select exterior-rated angles specifically approved for a 45 mm timber member, plus the manufacturer's specified connector screws and hole schedule. Ordinary decorative corner braces and generic deck screws are not substitutes.
80, 120 and 180 grit abrasives, exterior timber finish, brush, and end-grain treatment if required for your timber. Optional non-absorbent feet must be allowed for in the finished height.

Before cutting: confirm a suitable angle-and-fastener combination with your timber or hardware supplier. This plan does not specify a tested hardware assembly or load rating. For public/commercial seating, use a professionally specified, compliant design instead.

02 / YOUR WORKSPACE

Set yourself up.

Accuracy matters more than a large tool collection.

Measure & cut

Tape, pencil and combination square
Mitre saw with sufficient capacity, or a circular saw with a clamped straightedge
Stable workbench and timber supports
At least four clamps
Two 6 mm spacers

Drill & finish

Drill/driver and compatible screw bit
9 mm wood bit, long enough for 135 mm joints; check bolt supplier's clearance requirement
Pilot bit matched to the screw's root diameter and timber
Countersink, sockets/spanners
Sander or sanding block

Work safely. Wear eye and hearing protection and suitable respiratory protection for the dust. Clamp stock; keep hands clear of blades, support offcuts, and isolate tools before adjustments. Do not wear loose gloves near rotating equipment. Follow each tool's manual. Never burn treated timber or its offcuts.

READ THE PLAN

Everything
lines up.

The seat overhangs the frame by 50 mm at each end and 30 mm at the front and back.

Plan view · dimensions govern, not screen scale. Frame: 1,100 × 387 mm. Internal crosspieces: 387 − 2 × 45 = 297 mm. Height: 405 + 45 = 450 mm. Depth: 3 × 145 + 2 × 6 = 447 mm.

03 / THE BUILD

From boards
to bench.

Read all steps before starting. Dry-fit first, fasten second. Check square at every stage.

Inspect, mark and make the cuts

Measure the actual timber thickness and width. This plan needs 45 × 145 mm boards and 90 × 90 mm posts; if yours differs, revise the geometry before cutting. Choose dry exterior-suitable stock and reject major splits, decay, loose knots and severe twist.

Trim a reference end square, measure from it, then mark across the board with a square. Put the saw kerf on the waste side. Cut the three slats, two long aprons, three crosspieces and four legs to the cut list. Label A–E lightly on hidden faces. Clamp identical legs together and verify equal lengths; do not stack-cut unless the tool is designed for it.

Check: Four matching 405 mm legs and square ends. Small errors here become a rocking seat later.

Sand while every face is accessible

Remove saw marks with 80 grit only where needed; move to 120 grit, then finish to the coating manufacturer's recommended grit (often 120–180). Lightly ease exposed corners, especially seat edges, without rounding joint faces. Keep faces that meet flat.

Vacuum dust. Treat cut ends if the timber supplier requires it. Pre-finish hidden faces if your finish allows, keeping joint surfaces clean. Let products dry as directed before handling. Do not trap wet timber inside joints.

Lay out the apron frame

On a flat bench, arrange the two 1,100 mm aprons on edge, with the 297 mm end pieces between them. All apron tops will sit flush with the leg tops, 405 mm above the ground. The outer rectangle is 1,100 × 387 mm; the apron depth is 145 mm.

Place one leg inside each corner, touching both adjacent apron faces. Clamp without bowing the wood. Each leg is 90 mm square; there is a 297 mm clear space between the long aprons. Keep the centre crosspiece aside for now.

Check: Both frame diagonals should match (approximately 1,166 mm). Measure to the same corners each time. Adjust clamps until square.

Mark staggered bolt holes

Each leg gets four through-bolts: two through its long apron face and two through its end apron face. Mark each face on the leg's width centre line, 45 mm from either leg edge. Measure hole heights down from the shared top of the apron and leg:

Long apron: hole centres at 35 mm and 85 mm below the top.
End apron: hole centres at 60 mm and 110 mm below the top.

The 25 mm vertical staggering keeps perpendicular bolt paths apart. The long-apron hole columns are 90 mm from each apron end. Each end-apron hole column is 45 mm from its end. Check all marks against the actual clamped leg positions; use the diagram below to distinguish the two faces.

Drill and bolt the four corners

Keep each joint firmly clamped. Use a 9 mm clearance bit for M8 bolts unless your hardware instructions specify otherwise. Drill square through the apron and leg, backing the exit face with scrap to limit tear-out. Drill one marked path at a time, checking that the other face's holes are at their staggered heights.

Fit each bolt with a washer under the head and another under the nut. Snug all 16 bolts gradually, checking the frame stays square and the leg tops remain flush. Do not crush the wood. Ensure full nut engagement; select bolt length to avoid sharp protruding ends, or fit suitable protective caps. Do not substitute screws driven into end grain for these leg connections.

Check: Stand the frame on a truly flat surface. All feet should contact it, with no rocking or loose corners.

Install the central seat support

Mark the midpoint of each long apron at 550 mm from its end. Centre the 297 mm crosspiece on those marks, with its top flush with the frame. The support runs front-to-back between the long aprons, matching the end pieces.

Fit two approved exterior structural angles at each end of the support, one on each side, below the top surface. Use the connector maker's exact fasteners, specified holes, edge distances and installation instructions. Check that screws from opposing angles cannot collide or protrude through the 45 mm member. Choose another approved connector if they would. Do not use generic angle brackets without confirming their suitability.

Check: Lay a straightedge across both end aprons and the centre support. All three must be level with one another so each slat bears on every support.

Space and fix the three seat slats

Lay the three 1,200 mm slats lengthwise on the frame. Use 6 mm spacers between boards. Centre the seat: 50 mm overhang at each end, 30 mm front and back. Clamp in place and check that both end lines are straight.

For each slat, mark pairs of screw holes at three stations: 72.5, 600 and 1,127.5 mm from the left seat end. Place each pair 50 mm in from the two long edges of that slat (45 mm apart). That is six screws per slat, 18 in total. On the front and rear slats, the outer screw row enters the long apron and the inner row enters the crosspieces. Both rows of the middle slat enter crosspieces. Check underneath before drilling: every hole must land safely in solid timber and miss the connector hardware.

Drill clearance holes through the seat boards and pilot holes in the frame sized for the selected screws and timber. Countersink only enough to finish flush. Fit the 5 × 80 mm exterior screws, without overtightening, then remove spacers. Do not glue the slats to the frame; outdoor wood needs to move.

Check: Consistent gaps, supported slats and no screw points or proud heads.

Finish, inspect and place the bench

Ease any newly exposed sharp edges and remove dust. Apply the selected exterior finish to all accessible faces and end grain, following its coat thickness, drying and curing instructions. Do not sit on uncured finish. Lay out oil-soaked rags or store/dispose of them exactly as directed on the product; some oils can self-heat and ignite.

After curing, inspect every joint and connector. Place the bench on firm, level paving or decking, not soft soil. Check for rocking, sideways movement, splitting and exposed hardware. If it moves, stop and correct the joint or ground support before anyone sits down. Do not use it as a step, stand on it, jump on it, or rely on an assumed weight capacity.

Done: A 1,200 × 447 × 450 mm backless bench. Keep these measurements and the hardware instructions for future maintenance.

04 / MADE TO LAST

A little care.
A longer life.

After the first few weeks

Outdoor wood changes with moisture. Recheck bolt tightness and all joints after the first few weeks, then periodically. Tighten only enough to remove play; excessive force can crush fibres. Replace cracked or decayed parts before use.

Each season

Clean gently and let the bench dry. Keep leaves and soil away from the feet. Inspect the underside, end grain, screws and finish. Refresh the coating when its maker recommends, and store under a ventilated cover during prolonged wet weather. If rocking persists on level ground, investigate uneven legs or loose joints instead of wedging a loose object beneath a foot.

Notes & references

This is an original illustrative plan, not an engineered or independently load-tested product. Dimensions and joint positions are specific to this guide. Seek experienced help if you are unsure about wood condition, connectors or safe tool use.

Background reading: Simpson Strong-Tie: corrosion-resistant fastener selection. Match fasteners to the environment and timber treatment, and use compatible fasteners with connectors. Coastal or chemically exposed locations may require higher corrosion resistance.

For an alternative published design, see Ana White's simple outdoor bench. It uses a different design and cut list; do not mix its measurements with these.