Wall ties: cavity masonry and masonry veneer

TL;DR

Wall ties connect a masonry leaf to a frame or second leaf and are the only structural link keeping a brick skin on a building. Select the duty class from NCC 2022 Table 5.6.5a/5.6.5b (light duty for low-wind veneer, medium duty for N3+ or cavity), embed at least 50 mm into each leaf, and match the corrosion class to the site: 316L stainless within 1 km of the surf, 304L or 470 g/m² galvanised between 1 and 10 km, 300 g/m² galvanised inland. Omitted or under-embedded ties are a common defect that only shows up in a storm or when the brick skin starts to bow; by then the repair is costly.

What it is

A wall tie (also called a brick tie or masonry tie) is a mechanical connector embedded in mortar joints to transfer lateral load between a masonry leaf and either a structural frame (masonry veneer) or a second masonry leaf (cavity masonry). Without ties, a brick skin has no lateral restraint and behaves as a freestanding panel, which can fail in wind or seismic events.

Also known as: brick tie, cavity tie, veneer tie, masonry connector.

Wall ties must comply with AS 2699.1:2020, Built-in components for masonry construction, Part 1: Wall ties (verified 2026-05-11).

Properties

Property	Typical values
Material	Galvanised steel sheet or wire, stainless steel (304L or 316L), or engineered polymer
Standard	AS 2699.1:2020
Duty classes	Light duty, Medium duty, Heavy duty
Corrosion classes	R1, R2, R3, R4
Minimum embedment	50 mm into each masonry leaf
Typical form factors	Butterfly/double-triangle wire, corrugated strip, fishtail plate, screw-fixed channel

Grades and variants

Duty classes (AS 2699.1:2020)

Duty class	Typical application
Light duty	Masonry veneer in wind speed N2 or below (NCC 2022 clause 5.6.5(1)); cavity masonry at N1
Medium duty	Masonry veneer above N2; cavity masonry above N1; non-engaged piers; solid masonry
Heavy duty	Engineered masonry, tall parapet walls, post-frame structures; select per engineering design

Source: NCC 2022 Housing Provisions Part 5.6.5 (verified 2026-05-11).

Higher duty ties are suitable for lower duty applications. If unsure, specify medium duty, it is the minimum for most residential veneer above N2 wind class.

Corrosion classes (AS 2699.1:2020 Table 3.1)

Corrosion class	Coating specification	Typical exposure
R1 / R2	Galvanised sheet AS 1397 Z600 (42 µm) or hot-dip galvanised AS/NZS 4680 HDG300	Sheltered inland, protected from direct weather
R3	Hot-dip galvanised AS/NZS 4680 HDG470 (65 µm), or Grade 304L stainless	Moderate coastal (1-10 km from breaking surf) or industrial
R4	Grade 316L stainless steel or engineered polymer	Severe coastal (<1 km from breaking surf or <100 m from non-surf saltwater)

Source: AS 2699.1:2020 Table 3.1 (verified 2026-05-11); corrosion zone distances from NCC 2022 Housing Provisions Table 5.6.5d (verified 2026-05-11).

Note: Grade 316L and engineered polymer ties are suitable for all corrosion classes. Grade 304L stainless is suitable for R1, R2, and R3 only.

Where to use

External masonry veneer walls: ties connect single brick skin to timber or steel stud frame
Cavity masonry external walls: ties connect two masonry leaves across the cavity
Internal masonry walls requiring lateral restraint: medium duty ties to the structure
Parapet walls and freestanding piers: engineer specifies tie layout

Where NOT to use

Plain galvanised (Z600 or HDG300) within 1 km of surf or 100 m from other saltwater: use 316L stainless
Butterfly wire ties in high-wind zones (above N3): wire ties are light duty and may not meet the load requirement; check the duty class stamped on the product
Dry-stack masonry (no mortar): wall ties require a mortar bed for embedment; cannot be used in dry-stack systems
Polymer ties in applications exposed to UV without a masonry cover: check manufacturer’s UV rating

Fixing and installation

Spacing: masonry veneer (NCC 2022 HP Table 5.6.5a)

Stud spacing	Horizontal max	Vertical max
450 mm	450 mm	600 mm
600 mm	600 mm	400 mm

Spacing: cavity masonry (NCC 2022 HP Table 5.6.5b)

Direction	Maximum spacing
Horizontal	600 mm
Vertical	600 mm

Additional ties are required within 300 mm of corners, openings, and movement joints per NCC 2022 Part 5.6.5(2) (verified 2026-05-11).

Embedment

Minimum 50 mm into each masonry leaf (NCC 2022 HP Table 5.6.5c note, verified 2026-05-11)
Ties must slope slightly downward toward the outer leaf to drain moisture; a tie running level or sloping inward directs water to the frame or inner leaf
Do not allow the tie to bridge the cavity with mortar; keep the cavity clear

Pitch and drip

The tie must be bedded flat in the mortar joint with the drip or twist positioned in the cavity. The drip prevents moisture from wicking across to the inner leaf. Wire ties must have a twist or crimp for this purpose.

Tolerances and acceptance

Numerical

Item	Limit	Source
Embedment depth per leaf	50 mm minimum per NCC 2022 (verified 2026-05-11)	NCC 2022 HP Table 5.6.5c
Tie workmanship: embedment variation, plumb, spacing deviation	Per current HIA Guide to Materials and Workmanship and relevant state Guide. Verified numerical value pending HIA member access. [HIA-154]	HIA Guide / state guide

Visual acceptance at frame stage and lock-up

Ties visible at every stud (veneer) or at correct spacing (cavity): count ties in any 1 m² panel; confirm against the table above
Ties not bent down toward inner leaf or kinked: bent ties do not transfer load correctly
Cavity clear of mortar droppings on ties at each lift
Tie slope correct: outer end lower than inner end by approximately 15 mm per 100 mm of tie length
Corrosion class legible on product packaging and matches the site zone requirement

Working with other trades

Brickie: sets the ties as brickwork progresses. Frame must be straight and plumb before veneer starts; out-of-plumb framing creates a varying cavity width and ties may be under- or over-embedded
Carpenter (chippy): frame must be complete and braced before veneer ties are fixed; temporary diagonal bracing is removed only after the masonry has cured and tied
Engineer: non-standard situations (high wind class, parapet above 1 m, cavity over 75 mm, or tall single-storey masonry above 3 m) require an engineering specification for tie layout and fixings
Building inspector: ties are a pre-pour or pre-close inspection point; they are hidden once rendering or linings go on

Health and safety

Manual handling: tie installation is repetitive overhead and low reaching; use correct posture and rotate tasks to manage MSI risk
Brick and mortar face hazards: working adjacent to active bricklaying involves risk from trowel strike, dropped bricks, and mortar splash; use safety glasses
Working at height: tie installation above 2 m (on scaffold) follows the same safe work requirements as all scaffold operations: fall protection, platform integrity, edge guarding

Suppliers

Key wall tie brands in Australia:

Ancon (Leviat) (ancon.com.au): stainless and galvanised ties, remedial range
Helifix (helifix.com.au): remedial and new-build ties, including RetroTie, DryFix, ResiTie
Abey (abeytrade.com.au): cavity and veneer ties, publishes a corrosion zone selection map
Python Fixings (pythonfixings.com.au): PYTHON C remedial cavity tie system

[Sponsor / preferred supplier slot. ACCC disclosure required.]

Retrofit options

When existing ties have corroded, were omitted, or are under-embedded, the wall can be retrofitted without demolition using remedial helical or stainless steel ties drilled through the outer leaf:

Dry-fix remedial ties (e.g. Helifix DryFix): power-driven into both leaves through a small pilot hole; no resin required; fast and minimally invasive
Resin-bonded remedial ties (e.g. Helifix RetroTie, Ancon RemTie): inner leaf dry-fixed, outer leaf resin-bonded; suitable where the outer mortar joint is hollow or the drill hole needs filling
Helical cavity ties (e.g. PYTHON C): larger diameter helical ties providing verified shear capacity; used where structural interconnection is needed, not just lateral restraint

Diagnosis is the first step: a building engineer will tap-test the outer leaf (a hollow sound indicates tie failure or missing ties) and may use a borescope to inspect the cavity. Remedial tie design and spacing is an engineering task.

Source: Helifix Australia (helifix.com.au), Python Fixings Australia (pythonfixings.com.au) (verified 2026-05-11).

What can go wrong

Omitted ties: the most dangerous defect. No load path exists between the brick skin and the structure. The skin behaves as a freestanding wall and can collapse in high winds. Often only visible after a storm event or when brickwork starts to bow outward
Under-embedded ties: ties embedded less than 50 mm do not develop sufficient bond; the tie pulls out before the design load is reached. Common in sites where the mortar is too dry or the brick was placed after the mortar had stiffened
Wrong corrosion class for the site: a Z600 galvanised tie in a coastal zone will begin corroding within 10-15 years; corroded ties can expand to 7 times their original cross-section and crack the mortar joint, cracking the brick skin. Once the expansion cracks are visible, substantial repair is required
Ties sloping inward: water tracks along the tie into the frame or inner leaf; a common source of internal dampness that appears unrelated to the tie
Ties bridged with mortar snots: mortar droppings on ties bridge the cavity, directing water to the inner leaf. Clean the cavity and protect ties with hessian at each lift
Spacing too wide: long unrestrained spans allow the brick skin to deflect laterally under wind load; visual inspection from outside shows the wall is not plumb (either bowing out or a wavy face)
Incorrect duty class: a light duty tie in an N3 or above wind class may not transfer the design load; check the tie’s duty rating against NCC 2022 Table 5.6.5a before ordering

References

AS 2699.1:2020, Built-in components for masonry construction, Part 1: Wall ties (Standards Australia) (verified 2026-05-11)
AS 3700:2018, Masonry Structures (Standards Australia) (verified 2026-05-11)
NCC 2022 Housing Provisions Part 5.6.5, Wall ties (ABCB) (verified 2026-05-11)
Helifix Australia, Retrofitting wall ties (helifix.com.au) (verified 2026-05-11)
Python Fixings, Brick ties for existing walls (pythonfixings.com.au) (verified 2026-05-11)