Maximum opening size for welded-wire fabric lath with backing?

Maximum opening size for welded-wire fabric lath with backing?

• A. 2" x 2"
• B. 1" x 1"
• C. 3" x 3"
• D. 4" x 4"

Answer: (A)

Understanding plaster adhesion requires knowing how much open area the lath can have. For welded-wire fabric lath with backing, the openings must be kept to a manageable size so the plaster can grab onto both the wire and the backing without slipping through too far or creating voids. The standard maximum is 2 inches by 2 inches, which provides enough surface for a solid key and even thickness while preventing large pockets that could allow plaster to pull away or sag. If openings were larger, plaster could lose its grip, crack, or debond from the lath and backing; openings of 2x2 strike the balance between workability and bonding strength.

Understanding plaster adhesion requires knowing how much open area the lath can have. For welded-wire fabric lath with backing, the openings must be kept to a manageable size so the plaster can grab onto both the wire and the backing without slipping through too far or creating voids. The standard maximum is 2 inches by 2 inches, which provides enough surface for a solid key and even thickness while preventing large pockets that could allow plaster to pull away or sag. If openings were larger, plaster could lose its grip, crack, or debond from the lath and backing; openings of 2x2 strike the balance between workability and bonding strength.