Outdoor Storage Bench
A dual-purpose seat with dry storage below — perfect for cushions, garden tools, kids' outdoor toys or barbecue kit. Teaches lid geometry, weatherproof detailing and the difference good hardware makes.
What you'll need
Materials
- Frame timber, seat boards, marine ply or slatted base, A2/A4 stainless screws, stainless butt hinges or piano hinge, gas strut or chain stay, optional rubber feet or paving spacers.
Tools
- Mitre or hand saw, drill/driver, countersink bit, spirit level, clamps, sander, jigsaw for any cut-outs, exterior hinges and a soft-close stay are well worth the spend.
Material complexity: Medium
Allow one spare frame length and 10% extra on seat boards. Do not economise on hinges.
Main risk: A flat lid, or a solid seat with no gaps — water sits, the ply swells, and the inside stays damp.
Cut list
Default 1200×450×450mm box with a slatted lid. Confirm on site.
- Legs ×445×95mm × 450mm
- Long rails ×445×95mm × 1110mm (front and back, top and bottom, between the legs)
- Short rails ×445×95mm × 360mm (ends, top and bottom)
- Lid frame longs ×245×45mm × 1200mm
- Lid frame shorts ×245×45mm × 360mm
- Seat / lid slats ×6–7: 20×95mm × 1200mm, with 5–8mm gaps
- Base: 18mm marine ply 1110×360mm with drainage holes, or 20×95mm slats on two cross-battens
- Hardware: 3 stainless 75mm butt hinges, or one 1200mm stainless piano hinge; plus a lid stay or short gas strut
- A2/A4 stainless screws: 5.0×70–80mm for the frame, 4.5×40–50mm for slats
Step-by-step
Cut the box and check it is square
Cut legs, long rails and short rails from 45×95mm. Assemble one end frame, then the other, on a flat surface. Two stainless screws per joint. Check the diagonals are equal before you join the two ends with the long rails.
Tip: Clamp across the diagonals while you drive the screws if the frame racks.
Fit a draining base
Drop in 18mm marine ply with several 10–12mm holes, or slats on cross-battens with 5–8mm gaps. Do not trap water against the inside face of the legs. A slatted base dries faster.
Watch out: A sealed ply box with no holes becomes a paddling pool after the first storm.
Build the lid with a fall
Make a simple lid frame 5–10mm higher at the back than the front. Screw 20×95mm slats with 5–8mm gaps and a small front overhang. The fall is the detail that keeps the box dry.
Tip: Batch-cut slats and use a spacer strip so the gaps stay even.
Hang the lid on proper hinges
Fit three stainless 75mm butt hinges across the 1200mm back, or one 1200mm stainless piano hinge. Hinges go on the high side. Add a lid stay or short gas strut so the lid cannot slam.
Watch out: Two cheap brass hinges will rust, stain the timber, and fail. This is not the place to save a tenner.
Feet, finish and first season
Set the bench on rubber feet or stainless washers — not on lawn. Oil visible faces if you want to keep the colour. Empty the box after the first wet month and re-tighten the hinge screws as the timber settles.
Tip: A rubber bumper strip under the lid front gives a quiet close and keeps fingers safer.
Tips & traps
- Flat lid with no fall — water pools, soaks in, then drips inside.
- Solid panel seat instead of slats — traps moisture under cushions.
- Cheap hinges that rust and seize.
- No drainage in the storage base.
- No stay — a slammed lid splits the seat or pinches fingers.
Planning & timber detail
Why build this?
A storage bench combines joinery basics (frame and panel, hinged lid) with real outdoor durability lessons — drainage, sloped surfaces, end-grain protection, hardware choice. A finished one earns its keep within a week.
Where it works best
Covered or partly sheltered spots — under a porch, against a house wall, beside a summerhouse. Full-exposure positions work but reduce lifespan; mitigate with a drip detail under the lid and a slatted seat.
Planning notes
Slope the lid 5–10mm front-to-back so water runs off — this is the single detail that determines whether the storage stays dry. Put the hinges on the high side. Plan a small front overhang to throw drips clear of the box.
Typical sizes
Default: 1200mm long × 450mm deep × 450mm seat height.
Scale to 1500mm for three people or 900mm for a small porch. Storage volume on the default is roughly 150–180 litres — enough for 8–10 cushions or a barbecue kit.
Default dimensions
Default: 1200mm long × 450mm deep × 450mm high.
Lid fall: 5–10mm front-to-back.
Slat gaps: 5–8mm.
Front overhang: enough to throw drips clear of the box.
Design variants
Slatted lid (recommended) — drains and dries. This is the cut list above.
900mm porch bench — same section sizes, shorter longs, two hinges not three.
1500mm three-seater — add a centre divider in the box so the lid does not sag.
Suitable timber options
Cedar is the comfortable default — warm to sit on, easy to work, naturally durable. Iroko if you want heirloom durability and don't mind weight. Treated redwood for budget with the trade-off of more frequent finishing.
Fixing and finishing
Screw frame joints from inside where heads will be hidden. Stainless throughout — plain zinc bleeds rust onto cushions. Hinge the lid with three stainless 75mm butt hinges across 1200mm, or a continuous stainless piano hinge. Add a soft-close stay or short gas strut. Put the hinges on the high side of the lid so rain does not pool in the knuckle.
Hinge the lid with stainless butt hinges (3 across 1200mm) or a continuous piano hinge — much better than two cheap brass hinges. Add a soft-close stay or short gas strut so a slammed lid doesn't pinch fingers or crack the seat. A rubber bumper strip under the lid front gives a satisfying close.
Maintenance
Empty out once a year and check for trapped moisture in corners. Re-oil before the finish goes chalky (every 2–3 years). Tighten hinges after the first season as the timber settles.
Lift the lid on a dry day each spring, check the inside for damp corners and re-oil any visible weathering. Lubricate hinges with a dab of marine grease.
Timber behaviour
Durability
UC3 minimum for any timber on the bench — UC3 means timber kept off the soil (above ground). If the legs sit on paving or decking, put rubber feet or stainless washers under them so end grain does not sit in standing water. Avoid placing directly on lawn. You would only need UC4 (timber that sits in soil or stays wet) if a leg is buried, which this bench should never be.
Movement
Wide seat boards cup if fixed rigidly across width. Slatted seats with 5–8mm gaps drain and ventilate beautifully — the right call for outdoor use. Lid panels need slight room to expand, especially in summer.
Go deeper
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