Concrete Resurfacing

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                                6200 sq. ft. Grove Park Inn and Resort – Asheville, NC 

                               Resurface existing concrete, hand cut flagstone pattern

 

                             INTERIOR & EXTERIOR APPLICATIONS– 

Want to permanently cover up surface imperfections in existing concrete? Or turn a plain-jane slab from drab to fab? With today’s decorative overlays, it’s easy to give almost any concrete surface, indoors or out, a complete face-lift and at a lower cost than removal and replacement.

Although cement-based overlays have been around for decades, many of today’s systems blend polymer resins with cement, sand, and other additives to improve performance, wear resistance, and aesthetic qualities. Polymer-modified overlays can be applied in layers as thin as a credit card or up to several inches thick without delamination or failure. They adhere well to existing concrete and resist damage from salt, chemicals, UV exposure, freeze-thaw conditions, and abrasion.

 

When to Use a Polymer Overlay

Breaking out and replacing an existing concrete slab can be expensive, messy, disruptive, and time-consuming. With an overlay, you can give worn, lackluster concrete a decorative makeover or restore it to like-new condition in as little as a day and at a fraction of the cost (from about $2.50 to $4.50 per square foot, depending on the type of system installed).

Polymer-modified overlays are ideal for:

  • Adding pattern, texture, and color to exterior concrete slabs, including patios, pool decks, driveways, and sidewalks.
  • Resurfacing interior floors, including those previously covered with linoleum tile or carpeting (after removal of all residual mastic). With the use of stains or dyes, it’s possible to create colorful graphic designs, logos, or stenciled patterns.
  • Smoothing and leveling uneven or spalled concrete surfaces.
  • Restoring surfaces quickly with minimal downtime. Polymer overlays cure fast and some systems can support foot traffic within a few hours.

Not all existing concrete is a suitable candidate for an overlay. The concrete must be structurally sound, without gapping cracks, severe delamination, or an unstable sub base. Proper surface preparation of the concrete is also imperative to ensure good bonding of the overlay. Any non-structural cracks wider than hairline should also be repaired.

 

Types of Overlays

*Stampable overlays

A stamped overlay offers all the aesthetic benefits of conventional stamped concrete but is less time- and labor-intensive to install. The overlay mix is usually applied by a gauge rake (a tool with an adjustable depth gauge for achieving a uniform topping thickness) and then imprinted with stamping mats or texturing skins. These semi-flexible stamping tools are available in dozens of patterns, allowing overlay installers to duplicate the beauty and texture of natural stone, brick, slate, wood planking, and other materials. Overlay thicknesses range from 1/4 to 3/4 inch, depending on the depth of the imprint.

* Microtoppings and skim coats

These ultra-thin decorative toppings are applied by a trowel or squeegee in layers as thin as 20 mils, or a mere 0.02 inch. They can go on silky smooth and taken down to a featheredge. Or you can apply several coats to create a textured broomed or troweled finish. Some systems come pre tinted in a wide range of colors while others can be custom tinted by mixing in the desired amount of liquid coloring agent. Interesting color variations can be achieved by applying layers of different hues.

* Adding Color to Overlays

The color options for concrete overlays are limitless. You can buy mixes that are pre tinted like paint or you can add the pigment of your choice during mixing to produce custom hues. Once the overlay is applied, experienced installers can achieve more elaborate color effects, such as antiquing or marbleizing, by accenting the base color with layers of topically applied color. Some of the options include:

  • Dry-shake color hardeners
  • colored liquid or powdered release agents (typically used with stampable overlays)
  • Dyes
  • Chemical or acrylic-based stains
  • Tinted sealers

For more pizzazz, you can even seed overlays with decorative aggregates, color chips, or recycled glass.

 

Factors to Consider when Choosing a Resurfacing System…

Selecting the most appropriate resurfacing system often involves weighing performance attributes against aesthetic value. Here are some questions to ask to help you find a system that will strike the perfect balance for the job at hand.

What is the condition of the existing surface?

Does the concrete have a lot of cracks or gouges? Is the surface out of level? If so, choose a higher-build material, such as a self-leveling or stampable overlay that can be applied at a thickness of 1/4 inch or greater. Unless the surface imperfections are expertly patched or filled, they could telegraph through a thinner overlay, such as a microtopping or skim coat.

What conditions will the overlay be exposed to?

Be sure the topping or overlay system is tough enough to withstand all the conditions it will confront. Is the slab outdoors and subject to weather extremes and freezing and thawing? Is it a floor surface in a high-traffic area or subject to chemical, grease, and oil spills? Although most systems will stand up well to wear, chemical attack, and dirt penetration when properly installed and sealed, some are better suited than others for harsher exposure conditions. Often a higher-build material or a material containing aggregates will perform better in aggressive environments.

What is the installed cost?

The total cost of overlay installation will be higher if you are using stencils, stamping mats, or decorative engraving or saw cutting to pattern the surface. Using more than one coloring method (such as integral color combined with broadcast pigments and stains or dyes) will also boost the final cost.

How much maintenance is required?

A decorative overlay should always be coated with a compatible sealer to help protect it from water penetration, stains, dirt, and grease. Sealed surfaces will also be much easier to clean. Floors typically require only routine sweeping to remove any abrasive particles and occasional wet mopping with a mild detergent, depending on how much traffic they receive. Occasional pressure washing may be needed to clean exterior slabs. Exterior slabs should be resealed every 2-3 yaers for optimal protection. This is an easy process that anyone can do; simply power wash or scrub the surface with a mild detergent, allow to dry overnight and apply 1-2 coats of solvent based acrylic sealer by brush and roller.

Cleaning and sealing stamped and colored concrete should be done on a regular basis just like any other home maintenance. The frequency will depend on how high a traffic area to cars, foot traffic, water, and any chemicals the concrete is exposed to.

Concrete should be resealed every 2 or 3 years. If you wait longer, you may notice the color fade slightly. But just like waxing a car, reseal your stamped concrete and the color will be as vibrant as the day it was installed.

  • Rinse dirt/debris off stamped concrete surface with a garden hose or pressure washer.
  • Apply a small amount of liquid dish soap to surface and scrub with a push broom.
  • Rinse well with a garden hose or pressure washer until there is no sign of soapsuds.
  • Allow surface to dry at least 24 hours
    DO NOT APPLY SEALER TO A DAMP/WET SURFACE.
  • Once the surface is completely dry, apply the sealer as follows: Stir in one jar of Anti-Skid material to a 5-gallon pail of sealer. APPLY SEALER USING A 1″ NAP ROLLER ONLY. ANTI SKID MATERIAL WILL NOT TRANSFER THROUGH A SPRAYER. Apply sealer in approximately 2′ x 4′ sections. This will ensure full coverage without missed spots. Keep stirring sealer while applying to keep the Anti-Skid suspended in the sealer. Sealer should be applied when air temperature is above 55 F. Best results will be obtained by applying sealer during cooler temperatures — fall and spring — or before 10 am and after 4 pm in summer months when surface temperatures should be under 90 F.
  • A second coat can be applied after the first coat is tack free (not sticky to your touch).
  • Your stamped concrete should be resealed every 2-3 years to protect your investment. One 5-gallon pail of sealer will cover approximately 1,000 sq.ft.

 

Is it worth fixing?

Cracked concrete should be replaced if due to the three conditions listed below:

  • Widespread, deep cracks, settlement has occurred
  • Sunken Concrete
  • Frost Heave

Any patching compound used to patch these types of cracks will only be a short term fix. You definitely would not want to patch these cracks and then spend money resurfacing the concrete or doing a decorative topping.

 

Widespread, deep cracks, settlement has occurred…

When concrete is cracked all the way through the surface due to the weight of large trucks, improper preparation of sub grade, erosion of sub grade, or any other reason:

Get the advice of a local soils engineer on sub grade preparation for your area and material needed to prepare sub grade (sometimes existing material is OK)

  • Remove the concrete
  • Remove the sub grade
  • Replace sub grade with compactable material (sometimes existing material is OK)
  • Compact the sub grade
  • Pour back concrete

Sunken Concrete…

Sunken concrete occurs when the sub grade was not prepared properly. Loose dirt may have been used for the sub grade. When this dirt settles-sometimes due to sprinkler or rain water going under the concrete- the concrete is unsupported and will be more susceptible to sinking.

It is possible that the sub grade was compacted and the concrete was subjected to extreme weight which caused the concrete to sink.

Get the advice of a local soils engineer on sub grade preparation for your area and material needed to prepare sub grade (sometimes existing material is OK)

  • Remove the concrete
  • Remove the sub grade
  • Replace sub grade with compactable material (sometimes existing material is OK)
  • Compact the sub grade
  • Pour back concrete

Frost Heave…

Frost heave is very common in cold climates. Moisture in the ground freezes and the concrete pushes upward.

Get the advice of a local soils engineer on sub grade preparation for your area and material needed to prepare sub grade (sometimes existing material is OK)

  • Remove the concrete
  • Remove the sub grade
  • Replace sub grade with compactable material (sometimes existing material is OK)
  • Compact the sub grade
  • Pour back concrete