CONCRETE STENCILING

Types of Stencils:

Concrete stenciling has been used in both commercial and residential use for years and is an easy and inexpensive process can to add a fresh look to any concrete surface including entryways, sunrooms, and basements.  Concrete stencils can be used on new concrete or on existing concrete. 

Stencils are available in either paper (cardboard) stencils or plastic stencils.  Paper stencils are less expensive than plastic stencils but do not have the durability of plastic stencils as paper stencils usually deteriorate once they become wet.  Plastic stencils are cost upwards of $0.50 a square foot for installation.  There is a third type of stencils, which are made of paper but are wax coated on one side.  This allows for easy release when used on conventional concrete.  Because of the wax coating, they do not tear as easy as regular paper stencils.  These high quality paper stencils are suitable for applications such as cast-in-place, overlayment, sandblasting, and vertical applications.

Concrete stenciling utilizes the blocking technique, which is utilized prior to color application.  Because of this, it is possible to use customized colorization.  This will allow you to use a one-step application to apply several colors to your borders and or fields.

If the pattern you are planning to use is a repeating pattern, then it is important that make sure the forms are square.  If they are not, then your pattern will not be properly aligned with the form.  If the room or area were of an odd shape then perhaps it would be best to consider a random stone or geometric pattern, or if money is not an issue then you can have a stencil custom made so that the patter will fit the room or area perfectly. 

If you are stenciling a new concrete pour, it is important that the stencil is not initially applied too deeply and that it is visible on the surface.  The reason for this is that when you are floating and finishing, the stencil will be pushed deeper in the concrete.

Another critical step in stenciling is timing.  If you remove the stencil too early, it will not remove come out clean and breakage can occur.  On the other hand, if you remove the stencil too late, after a prolong period of curing removing the stencil could be very difficult.

Concrete stencils can also be used on existing concrete.  To use on existing concrete a thin decorative coating will be applied.

The following steps are used in applying concrete stenciling to existing concrete:

1.      Tape any surrounding surfaces you do not want sprayed with the thin decorative coating.

2.      Spread out the stencils over the existing concrete.

3.      Spray a thin coating of the decorative layer over the surface.  Make sure that you use the correct color. 

4.      Apply the finish coating.

5.      Carefully remove the stencils.

6.      Apply Sealer to the surface.

Using Stencils for Sandblasting and Acid Etching:

Concrete stencils templates can be used in also with sandblasting.  After you have stained and sealed the floor, apply your templates and sandblasted.  Once you have finished and have removed the templates, the pattern is then left natural or you can apply a stain.  However, if you decide to stain the area, you will need to clean the floor again.

Vinyl concrete stencil templates can be used with a gel acid.  Once you have applied the stain of your choice to your concrete flooring, do not seal your floor.  Place the vinyl templates on the concrete, then apply a gel acid to remove any stain, then remove the vinyl templates.  However, if you are custom staining the area, then the keep the vinyl templates in place and apply the stain.* 

*NOTE: Only hard-toweled finished floors can be restrained.  There may be some bleeding under the vinyl templates.

Stenciling New Pour Concrete Surfaces:

To save time, all stencils should be precut before the concrete is poured.  All forms must be set square in order to keep the intended patterns aligned.  Once the concrete is poured, the surface must be bull floated and then edged.  Place the stencils on the surface and adhered them to the surface.  The following tools can be used to apply the stencils to the concrete:

·        Speed trowel

·        Stencil roller

·        Fresno. 

DO NOT USE BULL FLOAT!

One the stencils have been properly applied cast the dry shake color hardener over the slab.  Make sure that you follow the color manufacturer’s instructions.  Make sure that you use the recommended amount of color so that you achieve the correct surface abrasion, wear resistance, and the true color of the product.  The majority of products on the market today require two applications in order to achieve the true color.  Making sure that you follow color manufacturer's instructions, you want to float the color into the slab with a bull float, then using a trowel close up the concrete.  To create optional finishes, you can use a broom, sponge float, wood float, cork float, or hard trowelled.  However, we strongly suggest that you practice creating these finishes on test projects to understand the finish each tool will create, before attempting them on your entire floor. 

As soon as you have finishes applying all coatings of color, your next step is to use a release agent according to the manufacturer’s instructions.  Once you have applied the release agent, the surface is ready for texture.  This can be with a roller, or seamless texture skin.

Once the concrete has lost its adherence to the stencil, the concrete will chip away from the stencil as you remove the stencil.  You will be able to walk on the slab at this time and within 24 hours, expansion joints are cut to ACI - American Concrete Institute standards.

After removing the stencils, you want to rinse the slab to remove most of the chips as well as the left over release agent.  Sprinkle a muriatic acid solution over the wet surface and scrubbed the surface using a stiff bristled brush to remove at least 90% of the release agent.  For large areas, you can use a floor buffer and a medium grit pad.  However, the concrete has to be sufficiently cured in order to use a floor buffer.  Once you have cleaned the concrete and reached the desired color, allow the concrete surface to completely dry.  You will then apply two coats of sealer.  For the first coat, we recommend 15 to 20% acrylic sealer, followed by a 25 to 35% acrylic for the second coat. 

*NOTE: Always apply the 15 to 20% sealer first!

Maintenance:

After the first year of use, clean and reseal the concrete surface using a 15 to 20% acrylic sealer.