INSTALLATION GUIDELINES METAL LATH

Lath Installation

Begin at the bottom right hand corner of the wall. Leave the paper backing overhanging at the top and left of the sheet. Offset paper backing has the paper overlapping 1-1/2 inches on one end and one side and retracted on the opposite end and side. The sheets should always be installed horizontally, perpendicular to the framing.

Laps

Minimum of 1 inch at edges with ends nested paper to paper, metal to metal. Apply the second sheet to the left of the first sheet lapping paper over paper and lath over lath. Place the third sheet centered above the first two sheets. This process is similar to that of laying brick. This staggers the vertical butt joint seams and allows a more uniform dispersal of stress.

Nailing Methods

On horizontal applications all nails shall be driven flush with base.

Lath Fasteners

(per ASTM C-1063)

• Concrete/Concrete Block: use 3/8 inch diameter shank, 3/4 inch minimum length. Use 4 powder actuated fasteners in the corners and 2 in the middle of long edges.
• Wood Framing: use 11 gauge, 1-1/2 inch nails with 7/16 inch heads (roofing nails 4d 1-1/2 in. x 1/4 in. head)
• Sheathing on wood framing: use 14 gauge 3/4 inch crown staples with a minimum 1-1/2 inch leg
• Metal Framing: use self drilling, self tapping #12 x 3/4 inch wafer head screws. Use of powder actuated fasteners is acceptable, but may cause spalling when shot to the substrate; follow manufacturer's instructions carefully.
• Insulating Concrete Forms: Consult specific ICF manufacturer.

Fastener Spacing

• Wood Framing: Spacing of nails, staples or screws is not more than 7 inches on center along the framing member
• Concrete/Concrete Block: 6 power actuated fasteners, 4 in corners, 1 on each side of long edge in center.

Cut and Trim to Fit

Standard aviation shears or metal cutting scissors are used for notching and snipping. A circular saw equipped with a metal cutting blade easily zips through steel lath to cut to desired lengths.

Wire Tie

(18-gauge) Lath is to be wire tied at 9 inches on center at edges, ends and at laps between framing members. On plywood sheathing, lath may be nailed or stapled in lieu of tying at 9 inches on center at edges, ends and at laps between framing members.

Accessories

Corner beads shall be used to protect all external corners with a plumb and true edge. Casing beads shall be used to terminate stucco or stone around doors, windows or other openings. Flashing shall be used where lath and stucco are to be applied on walls. Intersection of roof plane (i.e.: bulkheads, sidewalls, headwalls), a stucco stop, flashing/counter flashing shall be carried over the flashing to terminate the stucco and/or stone. Zinc alloy or vinyl accessories are recommended for exterior applications.

Important Installation Note

Lath accessories are designed to make plaster jobs easier, more efficient and provide the final product a more professional look. To ensure this, accessories should be attached every 18 inches with nails, staples or tie wires. For control joint, corner and casing beads, the nose can be used as a screed for the stucco brown coat, but must be embedded by 1/8 inch thickness of plaster on the final coat.

Jointing for Cracking Control

It is difficult to anticipate or prevent plaster cracks, but they can be largely controlled by means of expansion joints. The expansion joints should be installed between lath. The lath is to be broken underneath the expansion joint to function properly. Fasten the joints to the lath. Walls and ceilings that use metal lath for the plaster base should be divided into rectangular panels with control joint at least every 18 feet or at the juncture of a dissimilar wall, or in either direction in a length to width ratio of 2½ to 1, or in ceilings exceeding 100 square feet or walls exceeding 144 square feet in area.