Installation Instructions
INSTALLATION OF MANUFACTURED STONE VENEER
Prior to commencing installation of manufactured stone veneer, ensure that the WRB and ashing are
properly installed and integrated with each other. Before installing the manufactured stone veneer, it is
recommended that a minimum of 25 sq. ft. is laid out at the jobsite so there are a variety of sizes, shapes
and colors from which to choose. Mixing manufactured stone veneer sizes, shapes, textures and colors will
allow for variety and contrast in the design to achieve the desirable nished project.
MORTAR SCRATCH COAT
After the lath is installed, apply a nominal ½” thick layer of
mortar ensuring the lath is completely encapsulated with
mortar. The mortar should be applied with sufcient pressure
and thickness to fully embed the lath in the mortar. Total scratch
coat thickness is comprised of ¼” mortar embedded into and
behind the wire lath and ¼” mortar on the face of the wire lath.
Once the mortar is thumbprint hard, scratch (score) the surface
horizontally to create the mortar scratch coat.
Moisture curing the mortar scratch coat may help reduce
cracking and ensure proper hydration during curing. Before applying manufactured stone veneer, the
mortar scratch coat can be dampened so that the surface appears wet but free of standing water. It is
acceptable to install stone on a fresh mortar scratch coat once it has obtained a workable texture such as
thumbprint hard.
GROUT JOINTS
The back of each manufactured stone veneer should be entirely
buttered with mortar to a nominal thickness of ½”. Cover the
entire back of the manufactured stone veneer, not just the
perimeter. Buttered manufactured stone veneer should be rmly
worked onto the scratch coat and slid slightly back and forth or
with a slight rotating motion to set the manufactured stone
veneer. Achieve mortar squeeze out in a volume which results
in a full setting bed which covers the scratch coat completely.
With the proper mortar mix, moisture content, and scratch coat
preparation, the installer will feel the mortar start to grab within
a few seconds of the setting movement process. At this point, no further movement of that manufactured
stone veneer should be made as bonding will be broken.
If the manufactured stone veneer is inadvertently moved after initial set has begun, it should be removed,
mortar scraped off the back of the manufactured stone veneer and scratch coat, and then reinstalled
following the application process. Install manufactured stone veneer from the top down when possible to
minimize cleanup requirements.
Grouting may be done with a grout bag, lling joints to the desired depth, ensuring that mortar is forced
into all voids. Grout should be “thumbprint hard” before raking the joints. This curing time before
the grout is ready will vary signicantly with temperature and humidity. Use a wooden raking stick or
pointed tool to rake the joints to the desired depth. Extra precaution should be taken while raking so
the surface of the manufactured stone veneer is not damaged. Clean off the remaining grout debris on the
manufactured stone veneer surface with a dry, soft- bristled brush. To prevent mortar smearing,
DO NOT use a wet brush to treat uncured mortar joints.
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Disclaimer: This installation guide follows published MVMA and IAPMO specications.
Check your state building guidelines and codes for additional installation information.