How to Finish a Concrete Garage Slab
Pouring a slab for your garage is only the beginning of the project to create a useful long-lasting concrete surface. Once the slab has been poured, the concrete must be finished in place. The finishing process provides you with the final look of your garage slab. It also helps in the curing process of the slab so that your concrete surface is strong enough to provide necessary support. There are a variety of finishes, from a textured finish meant for extra traction, to a smoothly polished surface intended to bring beauty and function to your garage. Regardless of the finish you choose, your concrete garage slab will serve as a useful addition to your home. Does this Spark an idea?
Things You'll Need
- Concrete screed
- Bull float
- Trowel
- Concrete broom
- Concrete overlay mix
- Squeegee
- Concrete stain
- Hand pump spray bottle
- Plastic sheeting
- Masking tape
- Concrete grinder
- Diamond grinding pads
- Resin grinding pads
- Polishing compound
- Concrete sealant
- Concrete non-stick sealant
Instructions
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Level the surface of the concrete--if the concrete has just been poured--by dragging a screed across the concrete. Pull the screed bar by hand or connect it to a pipe to pull towards you to collect and evenly distribute any excess concrete on the slab. When finished, the slab should appear flat and even. If the concrete has already set due to prior installation, then proceed to Step 4.
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Float the concrete using a bull float to further level the concrete and bring moisture to the surface to slow concrete drying time and aid in the hardening process that occurs during concrete curing.
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3
Cut a set of control joints into the concrete slab, to prevent the slab from developing cracks due to temperature variances. Cut the joints to a depth of one and a half inches and place a joint every eight to twelve feet across the slab's surface using a trowel.
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4
Choose a finish type you wish to place on the slab. A broom finish is a textured finish created by pulling a broom through the wet surface of the concrete, roughing up the surface with a series of lines to increase traction for the slab. Dyeing or polishing the surface as a finish can provide for a more decorative garage floor.
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Pull a concrete broom across the surface of the slab to add texture. The broom should be pulled perpendicular to the slope of the slab if a slope has been installed. If the garage has a drain installed, direct the lines created using the broom towards the drain in order to aid water flow. If the concrete has set and you wish to create a broom finish, then spread a layer of concrete overlay mix onto the surface of the hardened concrete. Spread the overlay mix using a squeegee, and then allow the overlay to cure for 24 hours before applying a broom finish to the new surface.
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Color the surface of the garage slab if desired by spraying a layer of concrete stain onto the slab's surface. Place the concrete stain in a pump handles spray can and begin spraying at a corner of the slab and apply an even coverage across the surface of the garage. The stain will penetrate the surface of the concrete so that it will remain colored as the concrete wears. For increased depth of color, apply multiple layers of the concrete stain.
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Cover the slab with a layer of plastic to keep it from drying out too quickly and allow the concrete to cure for a week. Remove the plastic sheeting and wait two more weeks for the concrete to be ready for the final finishing steps. Use masking tape to tape the edges of the sheeting to the walls.
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Polish the surface of the concrete to a smooth shiny finish if desired. Run a concrete grinder equipped with a 32 grit diamond pad over the surface of the concrete to smooth any imperfections. After a pass with the 32 grit pad, change to a 60 grit pad and grind the surface again. Change to a 120 grit pad to create a completely level surface. Switch to a 50 grit diamond resin based pass to begin the polishing process. Work your way through increasingly finer grit pads until you do a final pass with a 3000 grit resin pad, polishing the concrete to a bright shine. Before the final pass, use a squeegee to spread a polishing compound across the surface of the slab to increase the shine.
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Apply a layer of concrete sealant to the surface of the concrete when the curing is complete or after polishing the concrete. For unpolished concrete, such as the broom-finished slabs, a transparent sealant can be used. Use a sealant containing a non-stick additive for polished concrete to help increase traction on the polished surface. Spread the sealant using a squeegee across the entire surface of the slab and then allow it to dry according to the manufacturer's instructions.
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References
Resources
- Photo Credit rough concrete surface image by angelo.gi from Fotolia.com
