Installation Instructions

MATERIAL REQUIREMENTS
RAINSCREEN
Rainscreen building techniques have been used in construction for many years. These techniques are
typically used to improve the escape of incidental water and decrease drying time. Rainscreen products
(such as drainage mats or formed polymer sheeting) or construction techniques (such as strapping or
furring) that create a capillary break/air space between the cladding and the primary water resistive barrier
can be effectively incorporated into manufactured stone veneer applications. Refer to the rainscreen /
drainage system manufacturer’s recommendation for applications with manufactured stone veneer wall
systems. Building codes may allow a single layer of WRB when a designed drainage space is incorporated in
the wall system (e.g. rainscreen).
LATH
All lath and lath accessories must be made of corrosion resistant material. All lath material must be self-
furred or use self-furring fasteners. The following materials may be used: 2.5 lb./yd
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self-furred metal lath
meeting ASTM C 847 or ⅜” rib, 3.4 lb./yd
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self-furred metal lath meeting ASTM C 847 or 18 gauge (or
heavier) woven wire mesh meeting ASTM 1032. Other approved lath may be acceptable for use with
manufactured stone veneer provided the lath meets an appropriate ASTM standard or the lath product
has an evaluation acceptance report from an ANSI Accredited Evaluation Service showing compliance with
IAPMO. Metal lath should be applied horizontally per manufacturer’s instructions and should overlap 2”
with a minimum of 1” on the horizontal and vertical seams. The ends of adjoining lath places should be
staggered. Metal lath is usually installed with the lath cups facing up. Metal Lath should be installed right side
up. Lath should be wrapped around inside and outside corners a minimum of 12” and to the next framing
member. Lath should be fastened every 6” vertically and maximum 16” horizontally into the framing
members and similar spacing on concrete wall surfaces. Do not end lath at corner framing. Alternate lath
should be installed per manufacturer’s instructions.
WATER RESISTIVE BARRIER (WRB)
Minimum two separate layers of any of the following: No. 15 felt complying
with ASTM D 226 for Type 1 felt, or Grade D paper (ICC-ES AC38), or
house wrap (ICC-ES AC 38), or any combination two separate layers of
these materials. One layer paper-backed lath meeting requirements for
Grade D paper may be substituted for the outer layer. Install WRB in
a shingle fashion, starting from the bottom of the wall. The inner layer
of WRB should be installed, along with ashings, to create a drainage
plane. The outer layer of WRB is intended to keep the scratch coat from
contacting the inner layer of WRB. The upper layer of WRB should lap
on top of the lower layer by a minimum of 2”. The vertical joints of WRB
must be lapped a minimum of 6”. Inside and outside corners must be
overlapped a minimum of 12” past the corner in both directions. The WRB
should be installed in accordance with manufacturer’s recommendations
and be integrated with all ashing accessories, adjacent WRBs, doors,
windows, penetrations and cladding transitions.
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Disclaimer: This installation guide follows published MVMA and IAPMO specications.
Check your state building guidelines and codes for additional installation information.