Garden benches · Guide 47
Build a Cedar Garden Bench With an Open Under-Seat Shelf
Build a 56-inch backless cedar bench with an 18-inch seat height and a slatted open shelf 8 in above the ground for light, dry garden items.
01 / See the shape
View the project
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All four legs must bear on the checked surface.
02 / Plan your build
Before you start
The shelf is kept separate from the bracing. Two removable 2 × 4 shelf slats H rest on the lower end rails D and a center bearer M. They sit 1.5 in above the lower side stretchers B and 2.25 in inside them, so stored items bear on the shelf, not on the stretchers. The open gaps along each side and between the slats let water and debris fall to the ground. They also keep the pocket-screw joints visible for inspection. Each shelf slat is held by three screws, so it can be raised slightly and slid lengthwise through an end opening to check the joints below. Allow 50 in of clear space beyond that end for withdrawal. The bench fails if the pocket-screw joints are driven out of square or loosen, letting the legs rack. It also fails if a seat or shelf screw is driven into a pocket-screw path, if the shelf is loaded with heavy wet items, or if someone sits alone on the 3-inch end overhang.
Where it goes
A firm, level, free-draining surface such as pavers or compacted gravel, at least 56 × 17 in with 30 in clear on each long side. Do not place it on soft or wet soil, a slope, a deck edge or near any drop. Keep 50 in clear beyond one end when removing the shelf slats for maintenance.
Footprint: 56 × 17 in seat over a 50 × 15 in leg frame. Allow 30 in clear on each long side for sitting and shelf access, 116 × 77 in in total
What to expect
Cut square ends on 4 × 4 and 2 × 4 stock, drill pocket holes with a jig and clamp joints square. Plan 8–10 hours including pocket-hole drilling and slat fitting, plus finish drying time.
A planning estimate for the hands-on work, once the materials are bought and the tools are set up. It has not been timed on a finished build.
Check the spot
- A firm, level, free-draining surface at least 56 × 17 in with 30 in clear on each long side, away from any drop or slope.
- Water must not pond under the shelf; check the spot after rain or a hose test before placing the bench.
- A flat assembly surface at least 60 × 30 in, large enough to clamp a 43 in rail without reaching across a moving cutter.
Stop and check first if…
- Stop if any board section differs from the parts table; recalculate every cut and position before continuing.
- Stop if a part splits, a pocket screw strips, a screw tip appears on an outer face or the frame will not square within 0.125 in.
- Stop using the bench if it rocks, a joint opens or a slat cracks. Unload it before opening a joint.
- Do not lengthen the seat or shelf, raise the seat or change the stock without fresh review of spans, racking and tipping.
Work safely
- Support 4 × 4 stock fully on both sides of the cut and clamp it. Never hold a short offcut by hand beside the blade.
- Clamp each rail in the pocket-hole jig before drilling and keep fingers clear of the stepped bit.
- Follow the saw, drill and finish manufacturer instructions. Keep guards in place and disconnect power before changing bits or blades.
- Oily rags from a penetrating finish can heat up and ignite as they dry. Lay them flat outdoors or seal them in a water-filled metal can before disposal.
Budget
We have not put a price on this one yet. Lumber and hardware prices change by store and season, so price the list under What you need at your local supplier before you buy.
03 / Gather and cut
What you need
L — Leg
4 pieces
Western red cedar or another decay-resistant species, nominal 4 × 4, actual 3.5 × 3.5 in. One 4 × 4 × 8-ft board: 0.25 in end trim + 4 × (16.5 + 0.125 kerf) = 66.75 of 96 in, leaving 29.25 in offcut.
Measure the section at both ends and the middle. Reject a board with end checks, a loose knot or twist. Mark the top end of each leg.
R — Top side rail
2 pieces
Same cedar, nominal 2 × 4, actual 1.5 × 3.5 in. One R from each of 2 × 4 boards 1 and 2, cut after H; see the 2 × 4 board layout calculation.
Mark the top edge and inside face. Pocket holes go on the inside face.
E — Top end rail
2 pieces
Same cedar, nominal 2 × 4, actual 1.5 × 3.5 in. Cut from 2 × 4 board 4 with D, C and M.
Mark the top edge. Both ends must be square so the end frame closes without a gap.
C — Seat cleat
1 piece
Same cedar, nominal 2 × 4, actual 1.5 × 3.5 in. Cut from 2 × 4 board 4.
Check that the length equals the measured distance between the R inside faces before cutting.
B — Lower side stretcher
2 pieces
Same cedar, nominal 2 × 4, actual 1.5 × 3.5 in. Both B from 2 × 4 board 3: 0.25 trim + 2 × (43 + 0.125 kerf) = 86.5 of 96 in.
Mark the top edge and inside face. B braces the legs and must not carry the shelf.
D — Lower end rail and shelf bearer
2 pieces
Same cedar, nominal 2 × 4, actual 1.5 × 3.5 in. Cut from 2 × 4 board 4.
The top edge carries the shelf slats. Choose straight, knot-free pieces.
M — Shelf center bearer
1 piece
Same cedar, nominal 2 × 4, actual 1.5 × 3.5 in. Cut from 2 × 4 board 4.
Check that the length equals the measured distance between the B inside faces before cutting.
H — Shelf slat
2 pieces
Same cedar, nominal 2 × 4, actual 1.5 × 3.5 in. One H from each of 2 × 4 boards 1 and 2: 0.25 trim + 50 + 0.125 + 43 + 0.125 = 93.5 of 96 in per board.
Use the two straightest 2 × 4 boards. Reject bow over 0.125 in or a knot near mid-span.
S — Seat slat
3 pieces
Same cedar, nominal 2 × 6, actual 1.5 × 5.5 in. Three 2 × 6 × 8-ft boards, one slat each: 0.25 trim + 56 + 0.125 = 56.375 of 96 in.
Reject splits within 6 in of an end, cupping over 0.0625 in or loose knots. Mark the seat face.
Pocket-hole screws
40 items
2.5 in coarse-thread pocket-hole screws, stainless steel or exterior-rated coating, for 1.5 in softwood Buy one box of at least 40. Confirm the length against the jig chart for 1.5 in stock before buying.
Two per rail end on R, E, B, D, C and M: 10 rails × 4 = 40. No connection capacity is inferred.
Seat slat screws
14 items
#9 × 2.5 in stainless steel or exterior-coated wood screws labeled for cedar and outdoor use Buy at least 14. Keep spares separate from the installed count.
S0 and S2 take 4 each into R. S1 takes 6 into E and C. Pilot and countersink each one.
Shelf slat screws
6 items
#9 × 2.5 in stainless steel or exterior-coated wood screws labeled for cedar and outdoor use Buy at least 6. These can come from the same box as the seat screws.
One per bearing: 3 per H into D, M and D. Leave the heads accessible so H can be removed.
Cut list
| Piece | How many | Cut length | Note |
|---|---|---|---|
| L — Leg | 4 | 16.5 × 3.5 × 3.5 in | Finished length × width × thickness; square ends unless the detail says otherwise. |
| R — Top side rail | 2 | 43 × 3.5 × 1.5 in | Finished length × width × thickness; square ends unless the detail says otherwise. |
| E — Top end rail | 2 | 8 × 3.5 × 1.5 in | Finished length × width × thickness; square ends unless the detail says otherwise. |
| C — Seat cleat | 1 | 12 × 3.5 × 1.5 in | Finished length × width × thickness; square ends unless the detail says otherwise. |
| B — Lower side stretcher | 2 | 43 × 3.5 × 1.5 in | Finished length × width × thickness; square ends unless the detail says otherwise. |
| D — Lower end rail and shelf bearer | 2 | 8 × 3.5 × 1.5 in | Finished length × width × thickness; square ends unless the detail says otherwise. |
| M — Shelf center bearer | 1 | 12 × 3.5 × 1.5 in | Finished length × width × thickness; square ends unless the detail says otherwise. |
| H — Shelf slat | 2 | 50 × 3.5 × 1.5 in | Finished length × width × thickness; square ends unless the detail says otherwise. |
| S — Seat slat | 3 | 56 × 5.5 × 1.5 in | Finished length × width × thickness; square ends unless the detail says otherwise. |
Tools
- Tape measure, combination square, straightedge, level and pencil
- Guarded circular saw or miter saw with capacity for 3.5 in stock
- Pocket-hole jig, stepped bit and drill collar set for 1.5 in stock
- Drill/driver, countersink pilot bit for #9 screws and a right-angle or stubby driver
- At least four bar clamps, a flat work surface, 0.25 in and 0.5 in spacers
- Sanding block or sander with 120 grit abrasive
Protective gear
- Eye protection during cutting, drilling and sanding
- Hearing protection and a dust mask suited to cedar dust
- Closed footwear; keep loose sleeves and gloves away from rotating bits and blades
04 / Put it together
Build steps
- 01
Confirm the site and intended use
Choose a firm, level, free-draining surface at least 56 × 17 in with 30 in clear on each long side. Lay a straightedge and level across the 50 × 15 in area where the four legs L will stand. Check both directions and both diagonals. List the items you plan to store and check that each passes through a 43 × 5 in front opening.
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Planning reference only: the four leg positions mark the area that must be firm and level.
Check: The surface is firm and level, water does not pond there, and every planned item is light, dry and fits the opening.
- 02
Inspect and measure the stock
Measure every board at both ends and the middle. The 4 × 4 must be 3.5 × 3.5 in, the four 2 × 4 boards 1.5 × 3.5 in and the three 2 × 6 boards 1.5 × 5.5 in, each at least 96 in long. Reject boards with splits within 6 in of an end, loose knots, twist, or more than 0.125 in bow. Set the two straightest 2 × 4 boards aside as boards 1 and 2 for the shelf slats H.
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Compare each measured board with the three actual sections used in this bench.
Check: All sections match the parts table, or work stops until every cut length and position is reworked for the stock you have.
- 03
Cut the four legs
Clamp the 4 × 4 with support on both sides of the cut. Square one end by removing 0.25 in. Cut four legs L at 16.5 in, measuring each from a freshly squared end. Label them L0 to L3 and mark the top end of each. Ease the bottom edges with a 0.25 in chamfer.
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Four matching legs, each measured from a freshly squared end.
Check: All four legs are 16.5 in within 0.0625 in and each cut end is square to the faces.
- 04
Cut the 2 × 4 rails and shelf slats
Square one end of each 2 × 4 by removing 0.25 in. From boards 1 and 2, cut one shelf slat H at 50 in and one top side rail R at 43 in each. From board 3, cut two lower side stretchers B at 43 in. From board 4, cut two top end rails E and two lower end rails D at 8 in, then the seat cleat C and shelf bearer M at 12 in. Label every part and mark its top edge.
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All twelve 2 × 4 pieces come from four boards; cut the long H and R first.
Check: R and B pairs match within 0.0625 in, the four 8 in parts and two 12 in parts match, and both H are straight within 0.125 in.
- 05
Cut the seat slats
Square one end of each 2 × 6 by removing 0.25 in. Cut one seat slat S at 56 in from each board. Choose the best face of each slat as the seat face and mark it. Ease the seat-face edges and cut ends with a 0.125 in round-over or a sanding block. Label the slats S0 front, S1 middle and S2 back.
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One seat slat per 2 × 6 board, seat face marked.
Check: Three slats lie flat face to face with ends within 0.0625 in and no splinters on the seat faces.
- 06
Drill the 40 pocket holes
Set the pocket-hole jig and drill collar for 1.5 in stock, following the jig instructions. On the inside face of each R and B, and on the face of each E, D, C and M that will face the bench interior, drill two holes at each end. Place them 1.75 and 2.75 in below the marked top edge. That gives 4 holes per rail on 10 rails, 40 in total. Clamp each piece in the jig before drilling.
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Every rail gets two pocket rows at each end, measured from its marked top edge.
Check: Count 40 holes, all on hidden faces and measured from the top edge, with no break-out through an outside face or edge.
- 07
Assemble the two end frames
Lay legs L0 and L2 on a flat bench, outer end faces down, with 8 in between their inner faces. Clamp E0 between them with its top edge flush to the leg tops, its outer face flush to the leg end faces and its pocket holes facing up. Clamp D0 the same way with its bottom edge 3 in above the leg bottoms. Drive 8 pocket screws. Repeat with L1, L3, E1 and D1 for 16 screws in total.
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E sits flush with the leg tops and D sits 3 in above the leg bottoms, both flush with the end faces.
Check: Each end frame is 15 in wide outside, both diagonals read 22.30 in within 0.0625 in, and the rail faces sit flush with the leg end faces.
- 08
Join the side rails and square the frame
With a helper holding the end frames upright on a flat surface, set them 43 in apart between inner leg faces. Clamp each R between the legs with its top edge flush to the leg tops, its outer face flush to the leg side faces and its pocket holes facing in. Clamp each B the same way with its bottom edge 3 in above the floor. Drive 16 pocket screws. Measure both top diagonals across the 50 × 15 in outside before removing the clamps.
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Side rails tie the end frames at the top and near the ground.
Check: Both top diagonals read 52.20 in within 0.125 in and all four feet touch the flat surface.
- 09
Fit the seat cleat and shelf bearer
Mark a line on the inside face of R0, R1, B0 and B1, 24.25 in from the left leg outer end faces. Clamp C between the R rails with its left face on the line, its top flush with the R tops and its pocket holes facing left. Clamp M between the B rails on the same line with its top flush with the B tops. Drive 4 pocket screws into each, 8 in total.
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C and M share one layout line at mid-length.
Check: C is flush with the R tops, M is flush with the B and D tops, and no screw tip shows on an outer face of R or B.
- 10
Sand and finish the parts
Sand all exposed faces of the frame, both H and all three S to 120 grit and remove the dust. If you use an exterior finish, coat every face, including slat undersides, cut ends and the leg bottoms. Let it dry for the full time on the product label before fitting any slat.
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Finish the frame here; coat the loose H and S slats separately on all faces.
Check: The finish is dry to the label standard and no raw end grain remains on the leg bottoms or slat ends.
- 11
Fasten the shelf slats
Lay H0 and H1 on D0, M0 and D1 with their ends flush to the leg outer end faces. Set a 0.25 in spacer against each leg and a 0.5 in spacer between the slats. On each H, mark points 1.75 in from its front edge at 0.75, 25 and 49.25 in from its left end. Pilot and countersink, then drive one #9 × 2.5 in screw at each point, 6 in total.
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Shelf slats bear on D and M, clear of the B stretchers.
Check: Gaps read 0.25 in at the legs and 0.5 in between the slats, the shelf top is 8 in above the floor, and each screw lands centered on D or M.
- 12
Fasten the seat slats
Lay S0, S1 and S2 seat face up with 0.25 in spacers between them. Set each slat end 3 in past the leg outer end faces, and the S0 and S2 outer edges 1 in past the leg side faces. Measure x from each slat left end and y from its front edge. S0 takes four screws at x 11, 20, 36 and 45, y 1.75, into R0. S2 takes the same x at y 3.75 into R1. S1 takes screws at x 3.75 into E0, x 52.25 into E1 and x 28 into C, each at y 2 and 3.5. Pilot, countersink and drive all 14 screws.
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Each slat has its own screw pattern matched to the rail beneath it.
Check: The seat measures 56 × 17 in, both gaps are 0.25 in and every head sits just below the seat face.
- 13
Place and level the bench
With two people, lift the bench by the R rails, not by a seat slat end or a shelf slat H. Set it on the checked site. Press down on each corner of the seat in turn. Do not use loose wedges under a leg L. Regrade or move the bench to firmer ground if it rocks.
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All four legs must bear on the checked surface.
Check: All four legs bear on the surface with no rocking when each corner is pressed.
- 14
Inspect before first use
Before seated use, obtain the review of the frame, connections and stability listed under limits. Check all 60 screws for seated heads and no tips breaking a surface. Check every rail joint for gaps and every slat end for splits. With the shelf empty, remove the three screws from H0. Raise it 0.25 in and slide it lengthwise out through the end opening; do not lift it through the seat. Allow 50 in beyond the end. Slide it back and refit all three screws. Place the planned items on H and check that none touch B. Sit near the center first, then over each pair of legs.
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Check both everyday access and the service route. The empty shelf slat rises 0.25 in and slides out through the end after its three screws are removed.
Check: No joint gap, split, protruding point, rocking or stored item touching B is found.
05 / Keep it sound
Care
After the build
- Place the bench on the checked site with two people lifting by the R rails. Confirm it does not rock before first use.
- Load the shelf only with light, dry items that rest on H without touching B. Keep the gaps between B and the shelf clear of debris.
Check it each season
- Before each season, unload the shelf and remove all three fixing screws from each H. Lift each slat 0.25 in clear of the bearers and slide it lengthwise through the end opening, keeping it between the legs; allow 50 in beyond that end. Inspect the D, M and B joints before sliding the slats back and refitting all six screws.
- Check seat and shelf screws for raised heads. Replace a cracked slat rather than adding a screw beside the crack.
- Sweep debris from the shelf gaps. Refresh any exterior finish according to its label when the wood looks dry.
If something looks wrong
- Bench rocks on one corner
- Move it to level ground or regrade the surface. Check that no leg has loosened from its rails.
- Frame racks or a rail joint opens
- Stop using the bench. Unload it, reclamp the joint flush and square, and replace any stripped pocket screw or damaged part.
- Shelf slat sags or touches B
- Remove the stored items. Check that M is flush with the D tops and replace a bowed H with a straighter 50 in slat.
- Seat slat splits at a screw
- Remove the slat and cut a replacement at 56 in. Pilot and countersink before driving the screws.
- Debris or water collects under the shelf
- Empty the shelf and remove the three fixing screws from each H. Lift each slat 0.25 in and slide it lengthwise through an end, then clear the gaps and the ground below. Move the bench if water ponds there.
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