Renewing an Old Concrete Slab

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Ver time, exposed concrete surfaces can start to show a lot of wear. Weather, hard use, and problems with the initial pour and finishing are among the most common causes of surface blemishes.

But despite a shabby appearance, old concrete is often structurally sound and can last for many more years. So instead of breaking up and replacing an old slab, you can easily renew its surface with concrete resurfacer. With the simple application, your concrete will have a freshly poured look and a protective surface layer that’s typically stronger than the slab itself.

Concrete resurfacer is suitable for any size of slab, outdoors or indoors. You can also apply it to vertical surfaces to put a fresh face on steps, curbs, and exposed patio edges. Depending on the condition of the old surface, the new layer can range in thickness from one sixteenth to one quarter inch.

Vi" drill with paddle mixer Duct tape or backer rod

Stiff-bristle broom Concrete resurfacer Eye protection and work gloves

After  Before

Concrete resurfacer offers an easy, inexpensive solution for renewing patios, driveways, paths, steps, and other concrete surfaces that have become chipped and flaked with age.

 

Thoroughly clean the entire project area. If necessary, remove all oil and greasy or waxy residue using a concrete cleaner and scrub brush. Water beading on the surface indicates residue that could prevent proper adhesion with the resurfacer; clean these areas again as needed.

Wash the concrete with a pressure washer. Set the

Washer at 3,500 psi, and hold the fan-spray tip about 3" from the surface or as recommended by the washer manufacturer. Remove standing water

 

подпись:
Fill sizeable pits and spalled areas using a small batch of concrete resurfacer—mix about 5 pints of water per 40-lb. bag of resurfacer for a trowelable consistency. Repair cracks or broken slab edges as shown on pages 286 to 287. Smooth the repairs level with the surrounding surface, and let them harden.

On a large project, section off the slab into areas no larger than 100 sq. ft. It’s easiest to delineate sections along existing control joints. On all projects, cover or seal off all control joints with duct tape, foam backer rod, or weatherstripping to prevent resurfacer from spilling into the joints.

Mix the desired quantity of concrete resurfacer with water, following the mixing instructions. Work the mix with a V" drill and a mixing paddle for 5 minutes to achieve a smooth, pourable consistency. If necessary, add water sparingly until the mix will pour easily and spread well with a squeegee.

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Saturate the work area with water, and then use a squeegee to remove any standing water. Pour the mix of concrete resurfacer onto the center of the repair area or first repair section.

Tool Tip ►

For improved color consistency, apply a thin, slurry coat of concrete resurfacer to seal the concrete substrate. An additional coat can be applied after two hours.

Spread the resurfacer with the squeegee using a scrubbing motion to make sure all depressions are filled. Then, spread it into a smooth, consistent layer. If desired, broom the surface for a nonslip finish (opposite page). You can also tool the slab edges with a concrete edger within 20 minutes of application. Let the resurfacer cure. Resurface outdoor projects when the temperature will stay above 50°F for 8 hours and the surface won’t freeze for at least 24 hours. Cover the area only if necessary to protect it from rain in the first 6 hours of curing (this may affect surface appearance and uniformity). During extreme wind or sun conditions, moist-cure the surface with a water fog-spray twice daily for 24 to 48 hours after application. Let resurfacer cure for 6 hours before allowing foot traffic and 24 hours before vehicle traffic (wait longer during cold weather).

Options for Resurfacer Finishes ►

 

For thicker resurfacing, simply add more layers of resurfacer as needed. Wait until the surface can support foot traffic—typically 2 to 6 hours—before applying the next coat.

Nonslip broomed finish: Within 5 minutes of applying the resurfacer, drag a clean fine-bristled push broom across the surface. Pull the broom backward in a straight line, moving across the entire area without stopping. Repeat in parallel rows until the entire surface is textured.

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Trowel application: A trowel is handy for resurfacing small areas. Use a stiffer mix for troweling—approximately 5 pints of water per 40-lb. bag of dry mix. Spread and smooth the resurfacer with a steel concrete finishing trowel.

Brush application: Resurface curbs, step risers, and slab edges using a masonry brush. Mix a workably stiff batch of resurfacer, and apply it evenly over the repair area. Finishing the surface with short brush strokes produce a mottled appearance; straight, continuous strokes create a broomed look.

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