Step-Leveling Deck

Dimensions

Cut list

Tools you'll need

• ✓

  Measuring Tape (5m or longer)

  Used for measuring each material.

• ✓

  Pencil and Carpenter's Square

  For marking layout lines and confirming right angles.

• ✓

  Saw

  Using home center's cut service is recommended.

• ✓

  Electric Driver

  Using an impact driver improves work efficiency.

• ✓

  Sandpaper

  Prepare 2 types: #120 and #240.

• ✓

  Level

  Essential for checking level during assembly.

• ✓

  Clamps (2 or more)

  Used for temporary fixing during joining.

• ✓

  Brush and Paint Tray

  Used for applying wood preservative.

• ✓

  Mason’s Line and Stakes

  Used for setting reference lines.

• ✓

  Shovel and Crushed Stone

  Used for ground leveling and stone bedding.

Materials

Build steps

1. 1

   Confirm Installation Site and Check Ground Conditions

   ≈ 30 min

   Measure the installation site for the step-elimination deck (1200×900×200mm). Check ground levelness, sunlight exposure, ground strength (susceptibility to soft or muddy conditions), and drainage paths.

   Measure

   W 1200 mm

   MeasureSTEP 1 / 10

   Tip

   • If the ground is soft, prepare the base adequately by laying a thick layer of gravel.
   • Ensure deck height allows ventilation underneath (200mm) to prevent moisture issues.
   • Check the direction of rainwater flow and position to prevent water pooling.

   Watch out

   • Installing on weak ground causes the deck to sink and tilt over time.
   • Water pooling locations accelerate wood decay.
2. 2

   Prepare Materials for Cutting

   ≈ 30 min

   Prepare 12 pieces of Western Red Cedar deck boards (20×90×1200mm), 4 pieces of 2×4 joists (38×89×1200mm), and 3 pieces of 4×4 beams (89×89×1200mm). Also prepare six 150mm square pier stones and ninety-six 90mm stainless steel coarse-thread screws.

   Cut

   Use the in-store cut service

   CutSTEP 2 / 10

   Tip

   • Western Red Cedar is highly water-resistant and a standard outdoor decking material.
   • Choosing materials with few knots yields a beautiful finish; this costs more but offers longer durability.
   • Stainless steel screws are essential outdoor; iron screws stain wood with rust.

   Watch out

   • Using SPF lumber results in decay within 3-5 years; use water-resistant species like Red Cedar or Ipe.
   • Insufficient screw length causes weak joint between joists and beams.
3. 3

   Install Pier Stones and Level Them

   ≈ 60 min

   Place 150mm square pier stones at the four corners of the installation area. Excavate the ground and bury the stones, then use mason’s line and a level to align the tops of all four stones horizontally. Ensure measured spacing between stones is consistent (approximately 450mm left-right and front-back).

   Build the frame

   Tighten joints firmly

   AssembleSTEP 3 / 10

   Tip

   • Pier stone leveling is the most critical step determining overall deck levelness; take ample time.
   • Using mason’s line allows simultaneous level confirmation of all four points.
   • Set stones slightly raised relative to ground for better drainage.

   Watch out

   • Unlevel pier stones cause the deck to tilt and cause objects placed on it to roll.
   • Placing stones where water pools allows moisture to reach wood and cause decay.
4. 4

   Sand Beams and Joists

   ≈ 30 min

   Sand the 4×4 beams and 2×4 joists progressing from #120 to #240 grit sandpaper. As they are for outdoor use, preparing the surface before finishing is important. Pay special attention to end grain where water penetration is highest.

   Sand

   #120

   SandSTEP 4 / 10

   Tip

   • Beams bear the most load; orient surfaces free of knots or cracks upward.
   • Joists are laid perpendicular to beams; maintaining level surfaces on both is essential.
   • Perform sanding outdoors and wear a dust mask.

   Watch out

   • Insufficient sanding hinders finish penetration, causing premature deterioration.
   • Leaving sanding dust causes uneven finish.
5. 5

   First Coating of Beams and Joists

   ≈ 60 min

   Apply wood preservative to beams and joists before assembly. Pre-coating joint surfaces which cannot be coated afterward is a key tip. Coat all surfaces with outdoor wood preservative (e.g. Xyladecor) and allow 24 hours to dry.

   Paint

   Watco oil / varnish

   PaintSTEP 5 / 10

   Tip

   • Pre-coating joint surfaces greatly enhances post-assembly wood protection.
   • Apply extra preservative to end grain.
   • Prioritize thorough preservation on parts closest to the ground, which have highest decay risk.

   Watch out

   • Assembling before coating leaves joint surfaces unprotected and susceptible to water ingress and decay.
   • Exposure to rain before drying causes the coating to run off; check weather forecast before coating.
6. 6

   Attach Beams

   ≈ 45 min

   Place three 89×89×1200mm beams parallel on pier stones spaced 450mm apart. Insert a waterproof sheet between beams and stones. Fix from below with stainless steel screws or dedicated hardware. Confirm levelness at four points with a level.

   Build the frame

   Tighten joints firmly

   AssembleSTEP 6 / 10

   Tip

   • Insert a waterproof sheet (rubber sheet acceptable) between the pier stone and beam to prevent capillary water rise.
   • Dedicated hardware ('pier stone brackets') can strengthen the connection and is available at home centers.
   • Orient beams lengthwise to align with water flow direction.

   Watch out

   • Omitting waterproof sheets allows water to rise from pier stones and rot beams.
   • Unlevel beams cause the entire deck to tilt.
7. 7

   Attach Joists

   ≈ 45 min

   Lay four 38×89×1200mm joists perpendicular across two beams at 200mm intervals. Drill 5mm pilot holes through joists and fasten each connection with two 90mm stainless steel coarse-thread screws (eight screws total).

   Build the frame

   Tighten joints firmly

   AssembleSTEP 7 / 10

   Tip

   • A 300mm joist spacing supports standard 20mm thick decking boards; wider spacing causes board bending.
   • Pilot holes prevent wood splitting; 4×4 beams are thick but prone to splitting.
   • Check joist top surfaces are level during fastening.

   Watch out

   • Joist spacing over 500mm causes decking boards to sag under weight.
   • Insufficient screw length failing to reach beams weakens joint strength.
8. 8

   Install Deck Boards

   ≈ 60 min

   Arrange twelve 20×90×1200mm Western Red Cedar deck boards perpendicular to joists. Maintain a 5mm gap between boards by inserting a 5mm thick spacer (thickness of one nail) while fastening. Drill 3mm pilot holes at joist connections and drive two 50mm stainless steel screws per board (total 18 screws).

   Build the frame

   Tighten joints firmly

   AssembleSTEP 8 / 10

   Tip

   • A 5mm gap provides essential drainage and ventilation; eliminating it causes water accumulation.
   • Using a 5mm spacer ensures uniform gaps.
   • Install boards with concave side facing down (joist side) to reduce walking discomfort caused by upward cupping.

   Watch out

   • Skipping board gaps leads to water retention and decay on underside.
   • Driving screws too close to board edges causes edge splitting.
9. 9

   Sand and Finish Deck Boards

   ≈ 90 min

   Sand all deck boards with #120 followed by #240 grit sandpaper, carefully attending to surfaces, edges, and end grains. Remove sanding dust thoroughly before applying two coats of outdoor wood preservative. Allow 24 hours drying between coats.

   Paint

   Watco oil / varnish

   PaintSTEP 9 / 10

   Tip

   • Sanding opens wood pores, improving finish penetration.
   • Apply extra preservative to end grains.
   • Choose stainless steel screws; iron screws rust within a year.

   Watch out

   • Incomplete finishing allows water ingress causing decay; coat thoroughly.
   • Exposure to rain before drying causes finish to run off; check weather before application.
10. 10

    Final Inspection and Maintenance Planning

    ≈ 30 min

    Inspect the entire deck for screw tightness, board levelness, uniform gaps, and finish coverage. Test drainage by pouring water. Avoid placing heavy objects during initial curing. Annual recoating preserves deck lifespan over 10 years.

    Done!

    Done — nice work!

    DoneSTEP 10 / 10

    Tip

    • Lightly sand with #240 grit and recoating annually extends life beyond 10 years.
    • Remove leaves and mud monthly under the deck to eliminate moisture sources.
    • In cold climates, coat before winter to maintain protection through spring.

    Watch out

    • Neglecting outdoor maintenance causes finish peeling and decay within 2-3 years; annual recoating is vital.
    • Accumulated debris and soil under the deck cause decay from underneath if left unchecked.

Warnings

• ⚠️For outdoor use, wood preservative coating is mandatory (recoating recommended annually).
• ⚠️Use stainless steel screws (iron screws will rust).
• ⚠️Drill pilot holes before screwing to prevent wood splitting.
• ⚠️Install pier stones level (tilting causes joists to warp).

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