Manufactured stone can be installed with a general knowledge of masonry practices. Over brick, block or concrete foundation walls, metal lath should be applied to ensure a good bond. Over exterior wall construction, a weather resistance barrier must be applied first under the metal lath.
Product Installation Procedure
- Preparing the Surface for Manufactured Stone
Our stone veneers can be applied to any structurally sound surface. Due to its light weight, no special foundation or structural alterations are necessary. On masonry walls (block, poured concrete, full brick) install 2.5 galvanized mesh directly to surface using concrete fasteners with a minimum of ¾” length and a minimum 3/8” diameter head. For all wood or steel stud construction, all exterior sheathings should be covered with weather resistant barriers with an ASTM E1677 Type 1—such as Tyvek®. Apply a minimum 15 lb. felt paper as well. The 2.5 galvanized metal lath should be attached with galvanized nails or staples penetrating 1” into stud, 16” on center with nails 6” apart. Lath to metal studs should be done with non-corrosive self tapping screws having a minimum 1” in length and a minimum of 3/8” diameter head. Metal lath must overlap 4” at horizontal and vertical joints with vertical joint overlaps on a stud.
- Applying the Scratch
As a rule, lathed surface should be covered with a ½” thin coat mortar (Type S or Type N). The mortar should be applied with sufficient pressure and thickness to fully embed the lath in mortar. Once the mortar is thumbprint hard, scratch (score) the surface horizontally to create the mortar scratch coat. Before applying the stone veneer, the mortar scratch should be dampened so that the surface appears wet but free of standing water.
- Mortaring the Architectural Stone
Before starting to install manufactured stone, it is best to lay out the manufactured stone near your working area to give you a selection of stone for an area of the surface you wish to cover. Select a stone and apply a 1” thick, even layer of mortar to the back of the stone.
- Applying the Manufactured Stone
Press the manufactured stone firmly into place on the wall surface so that the mortar behind the stone squeezes out around all sides. Using a gentle wiggling action while applying the stone will ensure a good bond.
In warm weather, masonry surfaces may need to be dampened prior to installing the stone so that the moisture will not be drawn from the mortar to rapidly. To keep the stone clean during construction, start installing the stone at the top of the wall surface and work down. Install the corner pieces first for easiest fitting. When selecting stones, try to achieve a balanced pattern of shapes, sizes, colors, thickness and textures. Keep mortar joints between the stones as tight and as uniform as possible. Avoid long straight unbroken lines.
- Grouting the Joints
After all the stone has been applied to the wall surface, fill a grout bag with mortar, and in the manner of decorating a cake, partially fill the joints between stones with mortar. Be sure, when grouting, to cover any noticeable broken stone edges with mortar. If you prefer colored mortar joints, oxide colors can be added to the mortar prior to grouting.
- Striking the Joints
When the mortar joints become firm, use a metal striking tool to rake out the excess mortar to the desired depth and at the same time to force the mortar into the joints to thoroughly seal the joint edges. Be careful not to work the joints too soon or the mortar will smear.
Brush the mortar joints with a whiskbroom or soft brush to smooth and clean away the loose mortar. At the same time, broom off any mortar spots from the face of the stone. Loose mortar and mortar spots which have set for only a few hours clean up easily and should never be allowed to set overnight.
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