Anchored veneer
Veneer ties and the checks around them for anchored veneer: the permitted design method, tie spacing or the force in the tie, the cavity and tie components, backing and height limits, and the out-of-plane stability of the backing. TMS 402-22 itself is not on hand: this follows BIA Technical Note 3C (July 2026), written to the 2022 code. Section numbers are marked to verify. BIA's note is for brick; concrete masonry veneer follows the same chapter, but its unit limits have not been compared.
Inputs of the anchored veneer #
- Design method. Prescriptive Basic, Prescriptive Enhanced or Tributary Area. The Modeling Analysis method is not offered: a wall that needs it says so.
- Load that governs, out-of-plane load, seismic design category. The load is at strength level: wind from components and cladding, seismic from Fp.
- Veneer. Specified thickness, unit height and weight. Over 30 ft (38 ft at a gable) on wood or cold-formed steel, detailed for differential movement is your statement.
- Backing, height hb, deflection. The backing is designed elsewhere; you enter its deflection, under 0.42 of the strength wind load or the strength seismic load.
- Veneer tie. Type, wire size or pintle legs, spacing both ways. In the Tributary Area method, the stiffness and strength come from TN 3C Table 6 or from your test values. BIA asks for professional judgment on in-house data.
- Cavity. Drainage space, continuous insulation, sheathing. The sheathing counts unless it bears 100 psi or the ties reach the framing.
Auto-design varies the tie spacing both ways, fewest ties first. Tie type, method, cavity and backing stay yours.
Checks performed #
| Check | Basis (BIA TN 3C, reading TMS 402-22 Chapter 13) |
|---|---|
| Method permitted for the load and category, 75 % of the loads for corrugated ties | Table 1 |
| Tributary area and spacing, Prescriptive | Table 2: 2.67 ft² and 24 in. Basic, 1.78 ft² and 16 in. Enhanced |
| Force in the tie, Tributary Area: 2, 2.5, 3 or 4 p At by stiffness | Tables 6, 7 |
| Cavity width by tie and component; drainage at least 1 in.; BIA's 2 in. as a note | Tables 3, 4, p. 5 |
| Component at most half the joint | p. 6 |
| Tie type allowed for the backing | Tables 3, 4 |
| Corrugated ties on wood at most 30 ft, 38 ft at a gable; movement statement otherwise | Table 5, p. 8 |
| Backing deflection for stability, no interpolation | Table 10 |
| Unit thickness, height and weight | p. 2, p. 8 |
Fasteners, edges, running bond and seismic detailing come out as notes: BIA states them and there is nothing to calculate.
Limitations of the anchored veneer #
- The Modeling Analysis method is not built. It needs a model of veneer, ties and backing with cracked hinges; MDG Example 16.2-7 covers it.
- Stability analysis for a slender backing (hb / t over 167) is not built.
- The backing, its fasteners' strength, shelf angles and lintels (L/600), movement joints, water penetration and corbels are not part of it.
- The allowable stress level of the Tributary Area method applies 0.6 to wind and 0.7 to seismic to the strength-level load, ILX's reading.
- A tie's fasteners to the backing are listed, not calculated.
- BIA's examples say corrugated ties are excluded once engineered, though its Tables 1 and 6 give values for them. ILX flags that and leaves it to you.
Verification examples #
Verification status: 28 values compared in 15 examples (14 published, 1 hand calculations from the cited equations): 28 within tolerance, 0 recorded deviations. Code basis: partial. Only some provisions were read in the target edition; the rest rests on older editions, examples or summaries.
BIA TN 3C (July 2026): the five design examples of Appendix A, pp. 18-26, wherever they compute or decide something, and seven values of Table 8. Example 3 is the case ILX refuses: it needs the Modeling Analysis method. The allowable stress level of the Tributary Area method has no worked value: by hand. The code was not read: when TMS 402-22 and the Designers' Guide arrive, check section numbers, the corrugated question, and add MDG 16.2-x.