How To Make A Garden Corner Sofa | Cut List Inside

Building outdoor seating that fits your patio and lasts through the seasons is easier than it looks. This guide walks you through planning, cutting, assembly, finish, and cushions. You’ll get a full cut list, spacing dimensions that avoid wobbles, and a cushion planner so the seat feels as good as it looks.

Project Overview And Materials

You’ll build two bench sections that meet at a right angle, tied by a corner backrest. The frame uses exterior-grade screws, waterproof glue on key joints, and slats spaced for drainage. Choose naturally durable timber or treated softwood, then seal it. Allow a weekend for cutting and assembly, plus drying time for finish.

Cut List For A Standard 200 × 200 Cm Layout

The dimensions below make a tallish lounge seat with a 45 cm sitting height, 60 cm back height, and a seat depth that accepts 60 cm cushions. Adjust lengths to suit your patio.

Piece	Qty	Length
Front/Back Rails (45×70 mm)	4	200 cm & 140 cm
Side Rails (45×70 mm)	4	60 cm
Legs (70×70 mm)	8	45 cm
Seat Joists (45×70 mm)	6	57 cm
Corner Blocks (45×70 mm)	2	40 cm
Back Posts (45×70 mm)	5	60 cm
Back Rails (45×70 mm)	4	140 cm & 60 cm
Seat Slats (20×70 mm)	18	60 cm
Back Slats (20×70 mm)	12	60 cm
Corner Filler Panel (20×70 mm)	3	40 cm

Tools And Hardware Checklist

• Miter saw or handsaw with a cutting guide
• Drill/driver, pocket-hole jig, clamps
• Exterior screws (stainless in coastal areas; hot-dip galvanized inland)
• Waterproof wood glue (D4 PVA or polyurethane)
• 120- and 150-grit abrasives, sanding block
• Exterior oil or stain, brush, rags
• Rubber feet or plastic pads for leg bottoms

Choose Timber That Lasts Outside

For easy sourcing and value, treated softwood is the go-to. If you prefer natural durability, cedar, larch, or teak weather well. Whichever you pick, let boards acclimate, pre-seal end grain, and raise the legs on small pads to keep them off wet paving. For durability data across species, the USDA Forest Service Wood Handbook summarises outdoor performance across a wide range of timbers.

Fasteners And Glue

Use exterior-grade screws. In damp or coastal spots, stainless steel outlives zinc-plated hardware. Galvanized is fine inland if you refresh finish routinely. Keep a small bottle of waterproof PVA or polyurethane glue for the joints that see the most stress.

Cost And Time Snapshot

Expect a weekend build for a first timer: half a day to cut and label, a day to assemble, and a few hours of sanding and finish. Material costs vary with timber choice and hardware grade. Treated softwood with galvanized screws lands at the budget end; cedar with stainless hardware costs more but trims long-term upkeep.

Build A Corner Garden Sofa Frame: Simple Method

This build uses pocket-hole joinery for speed and repeatable accuracy. Traditional mortise-and-tenon works too, but pocket holes let beginners hit tight tolerances without a full cabinet shop. Either way, clamp every joint and check square.

Step 1: Cut And Label

Crosscut legs, rails, and joists to length. Plane rough edges if needed. Pencil the part name on the end of each piece. Pre-drill countersunk pilot holes in rails to reduce splits, and set aside offcuts for later spacers.

Step 2: Assemble The Benches

Lay out the first bench as a shallow rectangle: two legs, front and back rails, with joists spanning between. Glue and screw rails into legs. Add joists at 40 cm spacing. Repeat for the second bench, which is shorter to form the “L.”

Step 3: Tie The Corner

Stand both benches in position. Clamp a corner block inside the junction and screw through both frames into the block. This stiffens the inside corner and stops racking when people lean across the middle.

Step 4: Seat Slats With Drainage Gaps

Rip or buy 20 mm slats. Start at the front and work back with 8–10 mm gaps. Use two identical offcuts as spacers so gaps stay even. Fix each slat with two screws at every joist.

Step 5: Backrest And Corner Panel

Attach back posts at the rear legs and the inside corner. Run back rails between posts, then fit vertical back slats with the same gap as the seat. A small filler panel across the corner makes the cushions meet cleanly and feels supportive.

Step 6: Sanding And Edge Breaks

Soften all edges with 120-grit to stop splinters and to help finish stick. Round over the front seat edge slightly; it’s kinder behind the knees and improves water runoff.

Finish For Weather And Wear

Outdoor timber lives longer when it sheds water and blocks UV. Two approaches work well: a penetrating oil that you re-coat annually, or a high-build exterior stain that forms a flexible film. Flood any exposed end grain and the bottoms of legs. Recoat before the surface looks thirsty rather than after it fails. For routine care tips such as when to recoat and how to treat horizontal surfaces, see the RHS guidance on maintaining garden furniture.

Prep And Application

Vacuum dust, wipe with a tack cloth, and brush finish with the grain. Work in shade on a dry day. If you used treated softwood, let it dry a few weeks after purchase before applying film-forming finishes.

Weather-Hardening Details

• Seal end grain twice; it drinks finish.
• Keep fastener heads just below the surface to shed water.
• Add rubber or plastic feet under legs to break contact with wet ground.
• Leave a small reveal where rails meet legs so finish can bridge the joint.

Cushions That Dry Fast And Stay Fresh

Pick outdoor fabric with a high lightfastness rating and reticulated foam that drains freely. Sew simple box cushions with zippers, or buy ready-made pads sized for 60 cm modules. Add breathable underliners so water can escape through the slats.

Seat Height, Depth, And Angles That Feel Right

Lounge seating feels best around a 45 cm seat height with a 10–12 cm cushion, a 60 cm seat depth, and a relaxed back angle near 100–105°. If you need taller or shorter seating, adjust leg length; cushion thickness does the rest.

Cushion Size Planner

Location	Finished Size	Foam
Seat Pads (x3)	60 × 60 cm	10–12 cm reticulated
Back Pads (long)	140 × 45 cm	8–10 cm reticulated
Back Pads (short)	60 × 45 cm	8–10 cm reticulated
Corner Wedge	40 × 40 × 60 cm	Custom cut

Placement, Leveling, And Protection

Set the sofa on level ground so weight distributes evenly. Use plastic shims under low legs until the frame doesn’t rock. If you park it on grass, add stepping stones or wide pavers to spread the load and keep the feet dry.

Maintenance That Pays Off

Brush off leaves, give slats a quick wash with mild soap, and re-oil or restain as finish fades. Store cushions upright in a ventilated box when rain is forecast. Small habits like these stretch the life of both timber and fabric.

Reference Dimensions And Clearances

Use these working dimensions as you tune the design to your patio. Small changes make big comfort gains: a few millimetres on gap size, a little more lumbar angle, or an extra slat for tighter spacing.

Comfort Numbers At A Glance

• Sitting height: 45 cm with 10–12 cm cushion
• Seat depth: 60 cm to suit modular pads
• Back angle: 100–105° from seat
• Arm height (optional): 60–65 cm
• Slat gap: 8–10 mm for drainage

Why These Materials And Gaps Work

Exterior screws and weather-resistant timber hold up when rain, sun, and temperature swings would tear ordinary furniture apart. The slat gaps speed drying and vent cushions from below, and the corner block keeps the inside angle from twisting as people shift.

Smart Assembly Tips That Save Time

Make A Quick Spacing Jig

Cut two 8–10 mm plywood strips to use as spacers between slats. They keep the pattern even without constant measuring and speed the job.

Batch Your Cuts

Stack boards with a stop block on the saw so duplicate parts match. Equal lengths build square frames and avoid shimming later.

Dry-Fit Before Glue

Clamp the rails and legs together without glue and check for square corners. When your diagonal measurements match, lock it in with glue and screws.

Pocket-Hole Settings

For 19–21 mm slats, use the 19 mm setting with 32–38 mm exterior pocket screws. For 45–70 mm rails, switch to 38 mm settings with 64–76 mm screws. Always test on an offcut first.

Common Mistakes And Easy Fixes

Frames That Rack

If the “L” flexes when you push the corner, add a larger corner block or a diagonal brace under the seat. Tighten any loose screws and check the floor for level.

Pooling Water On Slats

Increase the gap by a millimetre and round the front edge slightly. A light coat of oil after cleaning also helps water bead and run off.

Cushions That Slide

Stick outdoor hook-and-loop strips under pads, or sew short ties that wrap around back slats. Silicone dots on the slats add grip without showing.

Finish Peeling Early

Film finishes fail when applied to wet timber. If you used treated softwood, let it dry a few weeks after purchase, then apply thin coats in shade and avoid pooling in corners.

Placement Ideas And Layout Variations

On a small patio, leave the arms off to save width and keep the seating airy. For a pergola, add a tall back with a cap rail to echo the structure. If you host big groups, extend one bench by another 60 cm module and add a matching slatted table.

Light-Touch Care Calendar

• Spring: wash, sand light scuffs, refresh finish on worn spots.
• Summer: shade during heat spikes; stand cushions to dry after rain.
• Autumn: deep clean, re-oil or restain, check fasteners.
• Winter: store cushions, raise feet on rubber pads, or move to a covered spot.

Safety Notes While You Build

Wear a mask when cutting and sanding, and brush on finishes outdoors or in a well-ventilated area. Keep blades sharp, clamp workpieces securely, and lift with a helper if boards are long. Dispose of oily rags in a metal can with a lid to avoid self-heating. If you sand treated timber, avoid breathing dust and clean up with a HEPA vac.

Step-By-Step Recap

1. Plan your footprint and cushion sizes.
2. Buy timber, stainless or galvanized screws, and finish.
3. Cut parts to length; label each piece.
4. Assemble two bench frames with legs and joists.
5. Join frames at the corner with a solid block.
6. Install seat slats with even gaps.
7. Add back posts, rails, and slats.
8. Sand edges smooth and break sharp corners.
9. Seal, stain, or oil; flood end grain.
10. Fit quick-dry cushions and enjoy.