Concrete Expansion Joint Spacing Planner

Inputs

Results update as you type.

Structure
m
mm
Expansion joints
m
Δ°C
Joint layout along the slab2 → 3 panels of 30.00 m90 mexpansion jointscontraction jointsmyconstructioncalculator.comNot to scale
Diagram updates as you type.

Results

Check the working before you order.

Expansion joints
2→ 3 panels of 30.00 m
Movement at each joint12.0 mm (± 6.0 mm)
Minimum joint width24.0 mm for a ± 25% sealant
Contraction joint spacing (24–36 t)3.6–5.4 m use ≈ 4.5 m
Contraction joints per panel6 at 4.29 m each way
Saw-cut depth (¼ of slab)37.5 mm

Joint layout is a design decision: follow the joints on the structural drawings. Also add joints at changes in shape, re-entrant corners and where the building changes height.

Price This optional: add your own prices

Your prices are remembered on this device only.

Working
  1. Panels = ⌈90.00 ÷ 30.00⌉ = 3 → 2 expansion joints, panels 30.00 m
  2. ΔL = α × L × ΔT = 10.0×10⁻⁶ × 30.00 m × 40.0 °C = 12.0 mm
  3. Width = (ΔL ÷ 2) ÷ 25% = 24.0 mm (sealant moves ± about the installation width)
  4. ACI 360R: contraction joints at 24–36 × 150.0 mm = 3.60–5.40 m; many specifications cap this at about 4.5 m (15 ft)

Results are estimates for planning and material ordering only. They are not a substitute for structural design or approval by a qualified engineer. Read the full disclaimer.

Concrete Expansion Joint Spacing Planner byMy Construction Calculator: free construction calculators with the working shown.