Engawa-Style Bench

Dimensions

Cut list

Tools you'll need

• ✓

  Measuring tape (at least 5m)

  Used for measuring all parts

• ✓

  Pencil and carpenter's square

  For marking lines and checking right angles

• ✓

  Saw

  Using a home center's cutting service is recommended

• ✓

  Electric screwdriver

  Impact driver increases work efficiency

• ✓

  Sandpaper

  Prepare two types: #120 and #240 grit

• ✓

  Level

  Essential for checking horizontality during assembly

• ✓

  Clamps (2 or more)

  Used for temporary fixing during joining

• ✓

  Brush and paint tray

  Used for applying wood preservative

Materials

Build steps

1. 1

   Final Check of Parts and Tools

   ≈ 15 min

   Prepare two 2x6 lumber pieces (38×140×1800mm), four 2x4 lumber pieces (38×89×312mm), two 2x4 lumber pieces (38×89×1800mm), and forty 65mm coarse-thread screws. Tools include electric screwdriver, saw, measuring tape, carpenter's square, #120/#240 sandpaper, level, two F-clamps, brush, and paint tray. Stainless steel screws are recommended for outdoor installation.

   Measure

   W 1800 mm

   MeasureSTEP 1 / 19

   Tip

   • Prepare 50 screws (1.25 times the specified amount) to allow for mistakes.
   • For outdoor use, select stainless steel coarse-thread screws; iron screws rust within a year.

   Watch out

   • 2x4 and 2x6 lumber have the same thickness (38mm) but different widths (89mm and 140mm respectively). Confirm at checkout.
   • For transporting 1500mm long lumber, a minivan or larger vehicle is necessary; compact cars cannot fit it.
2. 2

   Securing the Work Area

   ≈ 10 min

   Secure a flat surface approx. 1800mm × 1500mm and lay down a blue tarp. Use two sawhorses placed side by side or a long workbench to support the 1500mm lumber horizontally. Select a day with little wind for outdoor work.

   Inspect

   No wobble ✓

   InspectSTEP 2 / 19

   Tip

   • The Engawa-style bench is intended for outdoor use. Assembling outdoors saves the effort of moving the finished bench indoors.

   Watch out

   • If the workbench is shorter than 1500mm, the lumber will sag and accuracy will suffer. Support both ends using two sawhorses.
3. 3

   Marking the Wood

   ≈ 15 min

   Use the carpenter's square and 2B pencil to mark cut lines and pilot hole positions on all parts: two top boards (1800mm), four legs (412mm), and two aprons (1800mm). On the back side of each part, write labels such as 'Top board A/B', 'Legs LF/LB/RF/RB', and 'Apron front/rear' to reduce confusion during assembly.

   Mark a line

   Use a try square

   MarkSTEP 3 / 19

   Tip

   • Bundle the four legs and clamp them to mark lines simultaneously, ensuring equal lengths.

   Watch out

   • Using inner or outer measurements of the carpenter's square causes a 3mm difference; always use the outer measurement (the scale side) for all parts.
4. 4

   Cutting Long Lumber

   ≈ 25 min

   Cut two 2x6 lumber pieces to 1500mm, two 2x4 lumber pieces to 1500mm, and four legs to 412mm. Using a home center's cutting service offers better accuracy and saves time. When cutting yourself, use a pull saw and cut 0.5mm outside the pencil line on the scrap side.

   Cut

   Use the in-store cut service

   CutSTEP 4 / 19

   Tip

   • Cutting 1500mm pieces yourself is physically demanding; home center cuts cost around 30-50 yen per cut and are recommended.
   • Clamp four legs together to cut them at once for consistent length.

   Watch out

   • If long lumber is not supported on the scrap side, the cut edge can chip. Always support both ends with sawhorses.
   • If even one leg is shorter, the bench will wobble. Ensure all four legs are cut to the same length.
5. 5

   Sanding (#120 then #240)

   ≈ 30 min

   Sand all parts first with #120 grit, then with #240 grit sandpaper. Sand the top surface (seat) carefully, and spend extra time on end grain as fibers tend to rise. Remove wood dust afterward with a vacuum cleaner.

   Sand

   #120

   SandSTEP 5 / 19

   Tip

   • Wrap sandpaper around a wooden block for more uniform sanding rather than holding it by hand.
   • Sand along the grain direction; sanding against the grain leaves roughness.

   Watch out

   • Rounding edges excessively results in an unappealing look; just 'run your hand over them' lightly.
   • Starting with #240 grit and skipping #120 does not remove roughness effectively; follow the order.
6. 6

   Preparing Pilot Holes

   ≈ 15 min

   Drill φ3mm pilot holes at two points where legs and aprons join, and four points where top boards join aprons. Use masking tape on the drill bit to mark drill depth and avoid drilling through.

   Drill a hole

   φ3mm

   DrillSTEP 6 / 19

   Tip

   • φ3mm pilot holes are 70% of the diameter of 65mm coarse-thread screws (4.2mm shaft) and ideal to prevent wood splitting.

   Watch out

   • Without pilot holes, cedar and SPF lumber almost always split, especially near edges; pilot holes are essential.
7. 7

   Temporary Assembly of One Side Leg Frame

   ≈ 15 min

   Using two legs (412mm) and one apron (1800mm), assemble a U-shaped frame and temporarily fix with F-clamps. Position the apron at seat height minus the top board thickness (350mm - 38mm). Confirm right angles using a carpenter's square.

   Build the frame

   Check for square

   AssembleSTEP 7 / 19

   Tip

   • Once positioned during temporary assembly, mark the joint surfaces with a pencil to avoid confusion at final assembly.

   Watch out

   • If the right angle is off when fixed, the frame becomes diamond-shaped. Always confirm square alignment.
8. 8

   Screw Fixing One Side Leg Frame

   ≈ 10 min

   Secure apron and legs with 65mm coarse-thread screws. Drive two screws per joint, staggered vertically. Set screw heads flush with or slightly (0.5mm) recessed below the surface.

   Drive screws

   コーススレッド 51mm

   ScrewSTEP 8 / 19

   Tip

   • Driving two screws slightly forming an inverted 'V' pattern improves pullout strength.

   Watch out

   • If screws are installed at an angle, remove them, fill the hole with wood filler, and fix screws at another position.
9. 9

   Assembling the Opposite Side Frame

   ≈ 20 min

   Use the first frame as a template to build the opposite side frame with identical dimensions. Place both frames side by side and check that apron positions and leg lengths match before final fixing.

   Build the frame

   Check for square

   AssembleSTEP 9 / 19

   Tip

   • Use the first frame as a template by stacking the second frame on top for precise positioning.

   Watch out

   • If left and right frames are asymmetrical, the top boards will be skewed. Confirm alignment by placing frames together.
10. 10

    Connecting the Left and Right Frames

    ≈ 15 min

    Stand the two frames parallel with 400mm spacing (depth) and place the second apron (1800mm) across the legs, temporarily fixed with clamps. Measure both diagonals with a tape measure; ensure differences are within 5mm before screwing.

    Measure

    W 1800 mm

    MeasureSTEP 10 / 19

    Tip

    • Measuring diagonals is a fundamental method for assembling box-shaped items; always measure both diagonals.

    Watch out

    • If diagonal difference exceeds 5mm, the frame becomes a parallelogram; loosen clamps and readjust.
    • Screwing both sides simultaneously causes distortion; fully fix one side before the other.
11. 11

    Level Checking the Leg Frame

    ≈ 10 min

    Place the assembled leg frame on the floor and check the level of all four sides with a level. If wobbling occurs, shave the longer legs by 1mm increments to equalize length.

    Check level

    Level ✓

    LevelSTEP 11 / 19

    Tip

    • The floor may itself be uneven; check level on multiple surfaces.

    Watch out

    • Excessive shaving shortens legs too much; always shave 1mm then check.
12. 12

    Positioning the Top Boards

    ≈ 10 min

    Lay the two top boards (1800mm) on the frame, leaving a 5mm gap between them using a spacer (a coin works). Ensure equal overhangs at both front and back ends beyond the frame edges.

    Lay the top board

    5mm 間隔

    Top boardSTEP 12 / 19

    Tip

    • A 500-yen coin is about 2mm thick; stacking 2.5 coins creates a 5mm spacer.

    Watch out

    • If boards are placed tightly together, rainwater accumulates causing rot. Leave at least a 5mm gap outdoors.
13. 13

    Fixing the Top Boards

    ≈ 15 min

    Drill φ3mm pilot holes at joint points of top boards and aprons, then fix with 65mm coarse-thread screws. Use four screws per board (two front and two rear aprons), totaling eight screws. Set screw heads flush with or slightly (0.5mm) recessed below the surface.

    Drive screws

    コーススレッド 51mm

    ScrewSTEP 13 / 19

    Tip

    • Avoid screwing in the center of top boards to prevent catching on clothing; limit screws to directly above aprons.

    Watch out

    • Protruding screw heads can hurt skin. If overdriven, remove and reposition screws.
    • Do not screw within 20mm of board edges; wood can split.
14. 14

    Rechecking Overall Level and Distortions

    ≈ 10 min

    After fixing top boards, re-check horizontality using a level and verify there is no creaking or wobbling. Sit on the bench; if it rocks, tighten screws at joints further.

    Check level

    Level ✓

    LevelSTEP 14 / 19

    Tip

    • Some distortions only become apparent under load; always perform a seated test.

    Watch out

    • Creaking noises indicate loose joints; do not ignore and tighten screws promptly.
15. 15

    Cleaning Before Painting

    ≈ 10 min

    Thoroughly clean all surfaces with a vacuum and a well-wrung cloth to remove wood dust and oils. Fill obvious screw head depressions with wood filler and smooth with #240 sandpaper.

    Inspect

    No wobble ✓

    InspectSTEP 15 / 19

    Tip

    • Cleaning before painting determines 80% of the finish quality; be thorough.

    Watch out

    • Leaving wood dust before painting causes rough textured surfaces; completely remove dust with vacuum and cloth.
16. 16

    Applying First Coat of Wood Preservative

    ≈ 30 min

    Apply a thin first coat of outdoor wood preservative (e.g., Xyladecor) evenly with a brush along the grain. Allow to dry in a shaded, low-wind area.

    Paint

    Watco oil / varnish

    PaintSTEP 16 / 19

    Tip

    • A 50mm wide brush suits the bench size well.

    Watch out

    • Drying under direct sunlight causes surface to dry quickly but interior remains damp; dry in shady conditions.
17. 17

    Applying Second Coat of Wood Preservative

    ≈ 30 min

    After 24 hours drying of the first coat, apply the second coat. Two coats are necessary for effective preservation. Pay extra attention to the seat surface. Avoid touching until fully dry (another 24 hours).

    Paint

    Watco oil / varnish

    PaintSTEP 17 / 19

    Tip

    • For the second coat, apply evenly without thickly covering, with the intention to 'cover.'

    Watch out

    • Rain before full drying washes the coating away; check weather forecast before painting.
18. 18

    Installation and Final Level Check

    ≈ 15 min

    After complete drying (48 hours), position the bench at the installation site. When placing on grass or soil, raise the legs on bricks or blocks to reduce decay. Use a level for final check and add foot pads to adjust any wobble.

    Check level

    Level ✓

    LevelSTEP 18 / 19

    Tip

    • Direct placement on grass keeps leg bottoms damp; raising on blocks is standard for outdoor DIY.

    Watch out

    • Sitting immediately after assembly may stain clothes with wet paint. Wait at least 48 hours for full drying.
19. 19

    Completion and Maintenance Record

    ≈ 10 min

    Conduct a final visual inspection of the completed Engawa-style bench. For outdoor use, lightly sand with #240 grit once a year and reapply the same wood preservative to extend lifespan beyond 10 years. Mark maintenance date and preservative name in pencil on the bottom of legs.

    Done!

    Done — nice work!

    DoneSTEP 19 / 19

    Tip

    • Keeping maintenance records facilitates future work; record date, preservative type, and location.

    Watch out

    • Neglecting maintenance for 2-3 years causes coating to peel and wood decay. Annual repainting is key to longevity.

Warnings

• ⚠️When used outdoors, wood preservative coating is essential (recoating recommended once a year).
• ⚠️Use stainless steel screws (iron screws will rust).
• ⚠️Drill pilot holes before screwing to prevent wood splitting.

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