DSA has issued Bulletin IR 25-4 titled ‘Self-Furring Lath 2019 CBC’ that was Revised 06/14/23 Under 2022 CBC. They state, “This interpretation of Regulations (IR) clarifies the acceptance of self-furring wire lath used as reinforcement for cement plaster on construction projects under DSA jurisdiction”.
Structalath III, Structalath Twin Trac 2.5, Structa Mega Lath, and Structalath V-Truss Walls and Ceilings are all self-furred laths and meet the product requirements of IR 25-4, specifically the 1/4 inch furring requirement.
These products are described with installation specifications in the Structa Wire IAPMO UES-Evaluation Report No 2017.
The California Supplement provides recognition that the products meet the requirements of the 2022 California Building Code (CBC) and the California Residential Code (CRC).
Bulletin IR 25-4 recommended these installation details:
- Lath should not be straightened by over-tightening, ensuring the lath remains offset from the backing.
- Furring out by ¼ inch over most of the wall area is required.
- The area within three inches of attachment points may measure less ¼ inch and not impact the embedment properties of the installed welded wire lath.
- Nails or staples must not be overdriven to prevent damage to the weather-resistant barrier.
Under the CBC and our ER report, it is noted that our lath attachment to horizontal supports shall comply with CBC Section 2507.3. This section requires a 1/2-inch crown by 1 1/2-inch length by No 9 ga ring shank hook staple to be applied at edge of each lath course at each framing member, omitting the 10d nail, if it captures a backing wire.
Structa Wire does not require the hook staple if there are two 16 ga staples at each overlap, one for each course. This provides equal or greater pullout strength as compared to the hook staple.
If you require further information, please do not hesitate to reach out to us at 1 800 887 4708.