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Masonry Garden & Fence Wall Height Calculator

NZS 4229 / Concrete NZ guidance. Indicative maximum heights for unreinforced concrete masonry garden walls and fences by wind zone and wall thickness. Scope: free-standing walls only — no surcharge, no retaining, no vehicle loads, no fill within 1 m of either face. NZS 4229 has been withdrawn; for any wall outside this scope use NZS 4230:2020 with a Chartered Professional Engineer. Results are indicative only and must be verified by a CPEng or LBP.

01 / Inputs

Measured from top of footing to top of wall.

Longer walls may need higher exposure zones for end regions.

Important note: NZS 4229:1989 has been withdrawn and replaced by NZS 4230:2020 for engineered masonry design. Garden and fence walls within NZS 4229 scope are limited to the heights shown in this tool. Walls outside these limits, or subject to vehicle loads, require specific engineering design per NZS 4230.

02 / Result

Maximum wall heights by wind zone (m) — NZS 4229 guidance

Wind Zone Single 90mm Single 140mm Standard 190mm Double 290mm
NZS 4229 — scope and limitations. This tool provides indicative maximum heights for unreinforced masonry garden and fence walls based on NZS 4229:1989 guidance and Concrete NZ recommendations. NZS 4229 has been withdrawn and replaced by NZS 4230:2020 for engineered masonry. The heights shown assume good construction practice, adequate foundations, and no surcharge loads (vehicles, buildings, or fill within 1 m of wall). Longer walls (>5× height) in H+ wind zones require H+ treatment for end regions. Cantilevered concrete masonry footings must extend minimum 300 mm below finished ground level. All designs must be verified by a Chartered Professional Engineer or Licensed Building Practitioner where any parameter is outside NZS 4229 scope.

Footing Requirements — NZS 4229 / Concrete NZ

i Min. footing depth below ground: 300 mm for all wall types (below frost line in cold areas).
i Footing thickness: Min. 150 mm concrete for single-leaf walls; min. 200 mm for double-leaf or piered walls.
i Footing width: Min. 2× wall thickness for single leaf; min. 600 mm for double leaf.
i Concrete grade: Min. 25 MPa (C25/30) for ground-bearing footings.
i Reinforcement: Minimum 2× D10 bars in footing for walls over 1.5 m height in H or VH zones.
i Drainage: Gravel backfill or weep holes required at 1–2 m centres at base for retaining situations.
! Mortar: Type M3 (1:1:6 cement:lime:sand) or Type M2 for standard masonry. Min. 10 mm joint thickness.
✓ Control joints: Every 6–8 m for unreinforced masonry to control shrinkage and thermal cracking.