Amidst this relentless winter, we have already seen many cases of scaling, spalling, and cracking of all sorts. We have seen damaged driveways, walkways, patios, and pool decks. Nearly every type of finish has been affected and the winter still continues. In this section, we’ll discuss a few unique products and how they can be used for making repairs in various cases.
Concrete Crack Repairs
We’ll start with crack repairs as a single approach can apply to many types of finishes such as stamped concrete, broom-finished concrete, and mag-finished (rosette) concrete. We are now promoting a very versatile material for crack repairs that is extremely fast to install, colorable with pigments and colored quartz, and very cost-effective.
Matchcrete Clear is a two-component resinous liquid made by Roadware. This product is UV stable, almost crystal-clear as supplied, and can be used in conjunction with colored silica sand and or pigments to help make a well-camouflaged crack repair. It’s also fairly quick-setting and extremely thin in viscosity which can help make quick, effective repairs for even very thin cracks. It’s important still, to understand how to make your crack repair as effective as possible. This may include chasing out the crack, in many cases, with a diamond blade or it may include creating new control joints or deepening other existing control joints to properly transfer the stress away from the crack. This is an excellent product with an unmatched ability to be camouflaged. See below for a demonstration video on the use of Matchcrete Clear…
Matchcrete Clear has a great versatility for other types of repairs as well, including some forms of spalling. Surface spalling can be cleaned then filled with dry sand and or stone (for exposed aggregate, select a stone that matches closely to the aggregate within the concrete. Aquarium stores have a great selection of stone and gravel in small bags as a tip). Sealant Depot stocks a variety of colored silica sand in small containers that will also be useful. First, prime the repair by wetting the area with the Matchcrete Clear. Using a combination of the sand or stone, fill the areas to be repaired by setting the dry materials inside the damaged area until you re-create a level surface. Then, simply dispense the Matchcrete Clear over the area. It’s thin viscosity will begin to wick through the loose fill that you installed and it will penetrate until it bonds to the concrete substrate. Deeper repairs may require layering of the Matchcrete Clear and sand. As an added tip, if you have to prep the surface by grinding or some form of minor demolition, try to collect your dust and or chips. By using these chips or dust as a light, final dusting over the surface of the still-wet Matchcrete, you may be able to create a nearly-perfect camouflage to your repair work. This technique can be used to repair nearly any and all cracks as well as spalling at the surface of the concrete that is deep enough to be practical (estimated depth of at least 1/16″ or deeper is fairly reasonable).
Video of Hairline Crack Repair in Concrete Driveway with MatchCrete ™ Clear
Additional and traditional approaches to repair spalling usually involve the use of a cement-based patching compound. The market literally has hundreds of excellent products but we’d suggest sticking to materials that are polymer-modified in some sense, whether it be a dry powder polymer blended in the bag or a polymer liquid admix. While most of these products can perform extremely well, it’s usually critical to keep patchwork relatively discrete-looking. For this reason, we suggest locating a patching mortar that allows for some color variety. In some cases, this may simply be concrete-gray or precast-white. Sealant Depot offers a product series called Patch-It from Renew-Crete which comes standard in light base and standard gray base (both of which can be pigmented), as well as a stainable base. For many repairs of surface spalling or deeper scaling, one of the Patch-It products will often be our top recommendation. Another clever patching method for going over colored concrete, can be done with Color Hardener. Since Color Hardeners are cementitious, they need only be mixed with water or a polymer liquid to make an effective patching mortar with a wide variety of color options. Further, Color Hardeners may be blended together with each other to help customize the color of your patching needs. Remember, patching can be an art but it’s also a learned trade/craft. With cement-based patches, be sure to use good practices which typically include good surface preparation, ensuring the surface to be SSD (Saturated, Surface Dry) prior to installation, and proper mixing of the product you’ve selected.
Since scaling issues can be extremely superficial, it can often be impractical to attempt to repair these areas with any of the aforementioned approaches. There are, however, many other products that can be handy to take advantage of when repairing a surface with shallow scaling problems. There are several products on the market that are used for antiquing stamped concrete. We have seen these products used beyond the scope of stamped concrete as well. Products such as Proline’s EZ-Tique and Brickform’s Antique-It are inexpensive, pre-colored, cement-basedaccessories that can be mixed with water to a very thin consistency. These types ofproducts can be mixed so thin that they can be used exclusively for cosmetic purposes (essentially a colored wash) or they can be mixed a little thicker than intended to function nearly is a thin grout. They are available in approximately 40 colors and you can always blend colors to customize your technique.
These antique wash products are a fantastic tool for helping to blend any of your patching attempts, so keep them in mind. Stamped concrete projects almost always are coated with some type of sealer, most commonly a film-forming sealer such as an acrylic. When damages occur on projects that are sealed this way, certain considerations should be made when performing repairs. Does your plan work over a sealed surface? Most times the surfaces that you will be repairing will have lost the sealer completely when the damage occurred so isolated repairs may not be affected greatly. However, it can be extremely time-consuming performing isolated repairs over an expansive scaling issue. If the scaling is scattered widely, but all damage is superficial, you may consider a holistic approach and treat the entire area with one broad treatment, rather than address each of a thousand little patches one-by-one. This can still be very cost-effective and easy. The most critical piece of information will be related to the sealer that was used. If you know the specific product, there is no more valuable knowledge than that. If the sealer is unknown, be wary of proceeding without testing or removing the existing sealer.
With a known solvent-based sealer, there is a very easy and effective method of camouflaging a scaling issue. Most times, it’s feasible to use the antiquing product with discretion over the entire area. Then, once dry, follow with a re-seal with a compatible product. Tip: if you apply your sealer coat by roller, you can effectively move or relocate some of your antiquing effects to better conceal those pesky, light-colored, scaled areas. Do this by using a roller saturated in sealer or solvent and massage the surface of these areas/patches in a circular motion. This should help to really disguise these areas. This technique should not be attempted without knowing good information about the existing sealer and it should be tested for results first.
Stripping sealer is generally a process reserved for extreme cases and is rarely necessary to make these types of repairs. Nevertheless, it should be a part of this discussion as it can be a primary part of many restoration projects, especially those of large size or those projects that exhibits many issues that need to be repaired. There are two general methods used for stripping sealer: chemical Stripping and mechanical removal. Given the choice, mechanical means are generally more thorough, less messy, and preferred by most of those who have ever tried the alternative. Chemical strippers come in a wide variety and at an even wider range of prices. For simplicity, I will be cynical about this and say you can either go green or save your green.
It’s common to find some nasty chemicals, like methylene chloride, that do a very good job of removing most paints, sealers, thin coatings and just about anything else. The bad news is that they can also take their toll on the person using them. For small areas, we’ve found that most big box stores sell a very effective product called Klean Strip KS-3. It’s not terribly expensive and it works well. For reasons of health, safety, and mess; we suggest trying to reserve this product’s use for only small areas and stubborn patches that resist other products or methods. This product does contain methylene-chloride which will cause chemical burns and presents other health concerns for you, your client, and any animals who may come in contact with it. Removal and cleanup of this product is also critical to be careful with. Grass, plants, and live landscaping of all sorts can and will be damaged or killed if exposed to this stuff. DO NOT DRINK!
For something a little more user-friendly, Sealant Depot offers several products. One of the better-known options isSoy-Gel from Franmar Chemical. Soy-gel is all natural, easily neutralized, and far more safe for everyone. To boot, it works very well. Soy-gel is effective on a very wide variety of sealers, paints, and coatings. While it effectively works to strip sealers, directions should be read carefully for best results. It may take some time in most cases to get the job done, but it really works with less effort than many “fast-acting” (fast to work, but also fast to dry and become ineffective quickly) solvent-based alternatives. Soy-gel is not cheap and it doesn’t cover a tremendous surface area, but if used correctly, it will become your preferred chemical stripping product when stripping is needed.
When the task of stripping with chemicals is too daunting, expensive, slow, inefficient, or labor-intensive, consider mechanical removal. Mechanical removal will include various forms of media-blasting (sand, soda, glass, etc.) as well as abrasive tools. If the finish of your substrate is not going to be resurfaced, then this process must be done with a delicate touch. Small, wet sand-blasting accessories are available for purchase and rental at Sealant Depot. This type of tool is not overly fast and results will vary based on the type of pressure washer that you use as well as the conditions of the concrete, but can prove very effective at removing sealers without disturbing the finish too much. Far more effective, are larger pieces of specialized equipment. Consult a local professional service, such as Atlantic Green Pro, about your specific needs. In most cases, the expense of subcontracting to such specialty professionals is well justified and results are rarely matched by chemical means.
While removing sealers and stripping the surface can prove challenging, it does open up the opportunity for far more restoration procedures. Once stripped of sealers, paints, and coatings, there are several resurfacing products that can be considered for restoration work. Deeper repairs can first be made with patching mortars. Cracks can then be repaired by various means. These types of repairs can now be made more simply before resurfacing is done and the repairs become far less visible. Some resurfacing products are so simple as to apply by roller. Products like Brickform’s Cem-Coat and Renew-Crete’s Roll Coat are cement-based resurfacers that can be roller-applied over stamped concrete, broomed, and mag-finished concrete, creating a new, colored, cement surface with ease and efficiency (material costs under $0.25/SF). Other products can be squeegeed, sprayed, or trowel-applied and broomed. These types of procedures are generally used for more intensive restoration work but it illustrates just how versatile you can be in the fields of concrete repair and restoration.
Damaged concrete is unavoidable, more so through the destructive conditions of winter 2014. Hopefully this discussion has illustrated how concrete is affected, how you can employ various preventive measures against cracking, scaling, and spalling,and how you can effectively repair damaged work.