Installation Guide

Installation Instructions
Welded Wire
Welded Wire: ¼’, furred lath is typically installed over open stud construction and with two (2) layers of
Grade “D” building paper over wood based sheathing. It also may be used in proprietary one-coat exterior
plaster systems recognized by the International Conference of Building Officials as well as the systems’
manufacturers. It is suitable for re-plastering over previous finished systems.
Installation:
1. Check flashing paper around all openings and ascertain the job is ready for lath.
2.
Where wood based sheathing has been installed, check that a 1/8” gap exists around the perimeter
of the sheets as suggested per the American Plywood Association.
3. The ¼” self-furred, welded wire fabric lath and building paper, shall be identified with product name,
manufacturer’s name and the International Conference of Building Officials – Evaluation Service
Research Report Number.
4.
Where ¼” self-furred, welded wire fabric lath is used, line wire is not required.
5.
The Uniform Building Code requires two (2) layers of grade “D” building paper over wood based
sheathing.
6. The Uniform Building Code requires the use of a minimum 26 gauge weep screed with a minimum
attachment flange of 3 ½”. Start building paper and lath at foundation of weep screed. The
building paper and lath must cover and terminate on the attachment flange of the screed.
7.
When welded wire fabric lath is used, extend the factory flaps. Lap building paper weatherboard
fashion, lapping not less than two (2) inches on horizontal and six (6) inches on vertical joints. Lap
succeeding courses of wire lath, minimum one (1) full mesh, wire to wire. After a field cut, paper
should be cut back a minimum of one (1) mesh at vertical and horizontal joints to allow for wire to
wire overlapping.
8.
All penetrations of exterior walls must be counter flashed with a minimum six (6) stripping of
flashing paper at sill, side and heads. Flashing at sill shall be over weather-resistive building paper
from below, at top and sides under building paper (weather board fashion).
9.
The welded wire, paperbacked, fabric lath may run parallel to rake of roof. Paper should be cut
back to provide proper wire to wire laps.
10. Vertical laps shall be made only at supports, but should not occur in line with framing members of
door and window openings.
11. Wire lath and building paper shall be cut neatly and snug against all openings and terminations.
12.
Exterior corner reinforcements are attached top and bottom and at both sides, a minimum eighteen
(18) inches on center. If exterior corner reinforcement is not used the wire lath must be furred out
at corners.
13.
Attach wire with approved divergent point staples, galvanized nails, galvanized eighteen (18) gauge
tie wire, clips or screws directly to support. Care should be taken to avoid unnecessary holes in the
building paper.
14.
The welded wire fabric lath is attached six (6) inches on center vertically, also top and bottom
plates and sixteen (16) or twenty-four (24) inches horizontal wood or metal stud spacing. The 3/8”
self-furred welded wire lath should be attached at the furring crimps. It is sometimes not possible
to make every attachment at furring crimps, but every effort should be made to return to these
points as
soon as possible.
15.
The welded wire fabric lath applied over wood based sheathing shall be installed with Uniform
Building Code approved fasteners and penetrate into supporting member the required distance.
Spacing of fasteners is the same as over open stud construction.
16.
These recommendations are subject to the approval of the local building inspection department in
which they are applied.
Important:
For a successful plaster job on all types of three coat laths each coat is important. The
emphasis must be placed on the scratch coat. It is the beginning of the finished product. Within this
scratch coat lies the strength of the bond that carries the weight of a level and uniform brown and finish.
The scratch coat must be (a) strong in mix (b) proper in consistency (c) applied as heavy as practical –
by machine or hand (d) worked with hand tools to form full keys and a base for succeeding coats.
Note: These installation instructions are intended to reflect the best construction practices and
compliance with current Uniform Building Code requirements. No guarantees or warrantees are implied
and it is suggested only trained and experienced lathers be employed to make installations.