Thursday
Nov032011
Stencils Application Instructions
These instructions will discuss the techniques for installing Faux Brick® running bond stencil on a rectangular slab. For purposes of this discussion, the two edges of the slab running parallel to the running bond stencil will be referred to as "sides" of the slab, and the two edges running perpendicular to the running bond stencil will be referred to as the "ends" of the slab.
- Layout
- Form work. It is extremely important that form work be square. If forms are not perfectly square, partial bricks at the ends and sides may grow noticeably larger or smaller from side to side or end to end.
- Expansion joints. Care must be taken in the placement of expansion joints. If there is only one expansion joint, it should be placed halfway between the two sides. Careful measurements should be taken to assure that it is parallel to the sides. If the slab will contain more than one expansion joint, then the distance between expansion joints must be exact multiples of four and one-half inches (the width of one course of bricks). Placing the expansion joints in this manner enables you to place the stencil so that expansion joints fall on a mortar joint rather than cut through the center of bricks.
- Place concrete, screed, and float in a normal fashion. Concrete slurry should have a slump of four to five, contain no calcium chloride, and no more than six percent entrained air. It is preferable to keep entrained air below three percent.
- Cut stencil into lengths approximately two feet longer than the length (end to end) of the slab.
- Snap a center line from side to side equidistant between the two ends.
- While the concrete is still wet (surface should have a moisture sheen), begin laying the lengths of stencil on the surface of the concrete. If there is standing water, it should be removed mechanically. Begin laying the stencil at one of the expansion joints or at either side if there are no expansion joints. The stencil is placed by two men holding each end of the stencil and lowering the trailing edge onto the surface while holding the leading edge twelve to eighteen inches above the surface. The long mortar joint at the trailing edge of the stencil should lie in the expansion joint or the form at the side if there is no expansion joint. The short mortar joints (those running perpendicular to the running bond stencil) should lie on the center line mentioned in step 4 above. If the trailing mortar joint does not land properly, pick the stencil up and repeat this step. Do not attempt to pull the stencil sideways to line it up with the center line or expansion joint as this will create wrinkles and distortion. When the trailing edge of the stencil is properly placed, gently lower the leading edge onto the concrete, making sure that the short mortar joints land on the center line. Repeat this step working outward to the sides and overlapping the mortar joints on the trailing edge of the stencil with the mortar joint or the leading edge of the previous section of stencil.
- Pass a stencil roller over the surface to embed the stencil into the surface of the concrete.
- Apply color hardener according to manufacturer's specifications.
- When the concrete has cured sufficiently to bear weight, float trowel or broom finish the surface.
- Lift out the stencil when the concrete has stiffened sufficiently to allow clean edges on the bricks. You may test this by lifting out a small portion along the end. In general, the stencil should be removed when pressing your finger on the surface no longer leaves a fingerprint.
- Blow loose particles and chips off with a mechanical blower and spray the surface with a resin base sealer and curing compound.
- Dismantle forms.
- If edges of slab will be exposed after landscaping, then edges may be finished as follows: Brush on a thick viscous mixture of color hardener and water. Using a screwdriver, scrape out a slot at the appropriate locations where the mortar joints should be located. This should be done within 24 hours of pour.
These are very general instructions for a simple rectangular slab. For more detailed instructions on particular situations, please call our technical staff at 318-379-2000.
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