What's inside
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A cedar garden bench is a good first outdoor furniture project because it does not require complex joinery, yet it teaches accurate measuring, edge preparation, sanding, and outdoor finishing. This version uses a simple leg-and-apron frame, exterior screws, and several narrow seat slats cut with a shallow curve. The result is more comfortable than a flat bench and forgiving of minor beginner mistakes.
Plan on a full weekend for cutting, assembly, and finishing. Cedar is relatively soft, so the work goes quickly, but it dents easily and can split if you drive screws too close to an edge.
Contents
Bench Design and Materials
The finished bench is approximately 48 inches long, 18 inches deep, and 18 inches high. Those dimensions suit one or two people and keep the seat low enough for a relaxed garden bench. Increase the length only after adding a center support; otherwise, the seat slats may flex.
| Part | Quantity | Suggested size |
|---|---|---|
| Seat slats | 5 | 1 x 4 x 48 inches |
| Legs | 4 | 2 x 4 x 16 inches |
| Side aprons | 2 | 1 x 4 x 15 inches |
| Front and back aprons | 2 | 1 x 4 x 41 inches |
| Center support | 1 | 1 x 4 x 15 inches |
| Seat spacers | As needed | Approximately 1/4 inch |
Use cedar rated for outdoor use, preferably clear or select stock if you want fewer knots. Construction-grade cedar is cheaper and works fine, but expect more checking, uneven edges, and cosmetic defects. A pack of exterior wood screws in a 2 1/2-inch length is suitable for the frame. Use shorter 1 1/4-inch screws for attaching the seat slats.
Tools and Preparation
You need a saw, drill, countersink bit, tape measure, square, clamps, and sanding equipment. A circular saw is enough. A miter saw makes repeated cuts faster, but it is not essential. A random-orbit sander is useful for the curved seat edges, although sanding by hand works if you start with 80-grit paper.
Before cutting, let the cedar sit outside under cover for several days if it has recently come from a warm, dry store. Keep it flat with stickers between boards. Cedar moves less than many hardwoods, but wet or twisted boards can change shape after assembly.
Wear eye protection and avoid breathing cedar dust. Cedar can irritate skin and lungs, so use dust collection or a properly fitted dust mask when sanding.
Cut and Shape the Curved Seat
Cut the five seat slats to equal length. Check each board for a usable face and place the better-looking faces upward. The curve is created across the width of the assembled seat, not along the bench length. A shallow crown in the center gives support without requiring steam bending.
Lay the five boards edge to edge on a flat surface. Use a flexible strip, thin piece of plywood, or a long ruler to draw an arc. Make the center of the arc about 3/4 inch higher than the ends. This is enough to feel comfortable without making the slats difficult to mount.
Number the boards, separate them, and cut each curve with a jigsaw. Clamp a straight scrap under the board near the cut to reduce vibration. Leave the line visible during cutting, then trim to it with a second pass if necessary. Keep the curves consistent; a high spot on one slat will make the finished seat look uneven.
Ease every exposed edge with 120-grit sandpaper or a small round-over bit. Do not leave sharp cedar corners. Sand the top surfaces through 120 and 180 grit, but avoid polishing the wood excessively because a very smooth surface can hold finish unevenly.
Build the Beginner-Friendly Frame
Pair one front or back apron with two legs. The top of each apron should sit about 1 inch below the top of the legs, leaving room for the seat slats. Apply exterior-rated glue only if the joints fit tightly; glue is not a substitute for screws in an outdoor structure.
Drill two pilot holes through each apron into each leg, then countersink the screw heads slightly. Cedar splits easily, especially at the end grain. Keep holes at least 3/4 inch from an edge and use a drill bit slightly smaller than the screw shaft.
Assemble the two side frames first, checking that each is square by measuring diagonals. Then connect them with the front and back aprons. Clamp the frame before driving screws. If the diagonals differ by more than 1/8 inch, push the longer diagonal inward until the measurements match.
Install the center support halfway between the side frames. Its top should be level with the apron tops. This support prevents the seat from sagging and gives the middle slats a solid fastening point. For a longer bench, add another leg pair and divide the length into sections rather than simply using thicker screws.
Attach the Seat Slats
Set the curved slats across the frame with roughly 1/4-inch gaps between them. Gaps allow rainwater and dirt to drain. Use identical spacers, such as a scrap of plywood, so the pattern stays consistent.
Center the slat layout from side to side and allow a small, even overhang at each end. Drive two screws at each end and two into the center support. Predrill every hole, especially near the ends of the slats. Cedar can split even when the screw seems small, and a split seat board is difficult to repair cleanly.
Do not pull a warped slat flat with excessive screw pressure. Clamp it first, or replace it if the bow is severe. Forcing it down can twist the frame and leave the seat under constant stress.
Finish and Weatherproof the Bench
Sand exposed areas again with 180 grit and remove dust with a brush or clean rag. Round over the bottom edges of the legs so they are less likely to chip when the bench is moved.
A penetrating exterior oil makes cedar look richer but requires regular reapplication. A semi-transparent exterior stain offers more color and somewhat better UV protection, while leaving the grain visible. Clear finishes usually need frequent maintenance and can peel or turn uneven outdoors.
Compare finish choices before buying:
| Finish | Best for | Trade-off |
|---|---|---|
| Penetrating oil | Natural appearance and easy touch-ups | Needs reapplication, often every 1–2 years |
| Exterior stain | Color and stronger UV resistance | More surface preparation when it eventually wears |
| Leave cedar unfinished | Lowest initial cost | Turns silver-gray and checks faster |
If you want to stain the bench, apply finish to all faces before assembly where practical, then add a final coat after assembly. Pay particular attention to end grain, screw holes, and the bottoms of the legs. Set the bench on pavers or rubber feet rather than directly on damp soil.
Seasonal Maintenance and Common Fixes
Build in late spring or early fall, when cedar is comfortable to handle and finishes can cure within the temperature range listed on the container. Avoid finishing in direct sun or when rain is expected within 24 hours.
Inspect the bench each spring. Tighten loose screws, sand splinters, and renew the finish before the wood becomes dry and cracked. If a seat slat splits near a screw, remove the screw, trim or replace the board, and redrill at least 1 inch away from the old hole. Do not simply drive a larger screw into the split.
For a cheaper build, construction-grade cedar and unfinished wood are reasonable choices. Spend more on straight seat boards and corrosion-resistant screws; those choices prevent the failures that are hardest to correct after assembly.