Many elements in a warehouse must be maintained, from the lighting to the materials handling equipment to the heating and cooling systems. But one of the most important parts of a warehouse to keep in good condition is actually just beneath your feet - the concrete floor.

Floors are the foundation of warehouse productivity, yet are often overlooked, even when repairs are obviously needed. If the floor's surface has cracks and gouges from heavy traffic or is dusty because it was improperly finished, efficiencies and equipment are suffering. Consequences of damaged floors include vibratory damage to equipment, in- creased wear of wheels, tires and casters, employee dissatisfaction, and excessive downtime for repairs, just to name a few.

Despite such negative effects, few warehouses report that their overall concrete floor condition is excellent (8%) or good (17%), according to a survey conducted of several warehousing and distribution facilities by Metzger/McGuire (800-223-6680), a manufacturer of industrial floor repair products. And 79% of the respondents admit that their companies have no floor repair budget, even though an even greater majority (87%) acknowledges increased vehicle costs due to floor defects.

There are various types of concrete floor deterioration resulting from long term use, design and construction deficiency, as well as abuse and neglect. Fortunately, many kinds of materials such as fillers, sealers and coatings are available to repair defects and keep your foundation strong and smooth.

Composed basically of cement, coarse aggregate, sand and water, concrete forms a highly durable industrial floor as long as it is constructed correctly.

Water is necessary to thoroughly mix the various concrete components, hydrate the cement and create a mixture workable enough for placement. The amount of water used is critically important. A concrete mixture with too little water will be difficult to properly place and finish, whereas a concrete mixture with too much water will result in a weak floor.

Once the cement is fully hydrated, the water must evaporate slowly over a protracted time period, a process called curing. During this period, which generally lasts a year or more, concrete naturally shrinks as it loses moisture. To accommodate this shrinkage and ensure that the floor's surface does not crack randomly, control joints are created, compelling the concrete to crack in straight lines. The concrete slabs are kept together by interlocking the concrete's large aggregate rocks and placing dowels between the slabs at the joints. As the concrete shrinks, joints must be filled with a substance rigid enough to support heavy traffic, yet flexible enough to allow the joints to open up as the concrete's water evaporates.

If any part of the construction process is substandard, floor defects will be unavoidable.

One of the most common problems of concrete floors is spalling, which is the deterioration of the concrete along the joint lines or edges of a slab. According to the Portland Cement Association (847-966-6200), spalls measure an inch or more in depth and six inches or more in diameter. Spalling can occur for a number of reasons-edges are not cured or formed correctly, joints are not filled to the proper depth, and fillers used are not firm enough to support traffic.

Random cracking is another problem that is usually the result of poor construction. There are several potential causes. Joints can be cut too shallow or spaced too far apart to force cracking in straight lines. Random cracks will also appear if the base underneath the slab is not formed evenly or compacted deeply enough to support concrete segments.

More harmful to the floor than random cracks is a rocking slab. When a floor has no dowels or secure aggregate interlock, the concrete slabs will move independently of each other. Under the weight of heavy equipment, the floor may allow one slab to move while the next remains in place. The equipment's wheels are then likely to damage exposed slab edges or be damaged themselves.

Surface dusting, though frequently ignored as a significant problem, also affects warehouses. As the National Ready Mixed Concrete Association (301-587-1400) notes, floors that powder under any kind of traffic and can be easily scratched have surface dust. Resulting often from an improperly finished or inadequately cured floor, surface dust can produce an unhealthy and unpleasant working environment.

The first step toward a better warehouse floor is an evaluation of the defect and repair requirements. For example, a joint separation problem requires a carefully applied semi-rigid filler to allow further shrinkage, while a small crack needs only a brushed-on protective coating.

Once the severity of the floor repair has been determined, the amount of time and knowledge necessary to perform the repair should be considered. For instance, fixing a small crack does not involve expert knowledge and halt traffic in an entire warehouse during a repair. However, coating an entire floor or repairing a spalled joint may require outside help from a specialist, not to mention a complete warehouse shutdown while the coating or filler cures.

Attention to environmental requirements is also critical. Some filler and coating materials contain volatile organic compounds, referred to as VOCs. When VOCs escape into the atmosphere, they can cause pollution and even serious health problems, so buildings must ordinarily be vacant while these products cure. A warehouse will not be able to use such products if it is located in one of the various states where VOC-containing products are banned or if food processing and other sanitary applications occur.

When such issues are addressed, a repair product can be selected based on its characteristics. Many materials are available as fillers and coatings. Plastic-like proprietary substances and polymer concretes like polyurea and methyl methacrylate cure quickly. While these fast-curing products support heavy equipment soon after application, they often set so quickly that personnel must be well trained in their application. Other polymer types include epoxies and urethanes, which offer good chemical and abrasion resistance. However, they typically have long curing times and high levels of VOCs.

Click on the icon to find out how concrete repairs are made.

Ideal for repairing spalled joints and filling random cracks and other surface defects, Tigerthane 220 is a flexible two-part polyurea elastomer seal made of 100% solids. The rapid-setting sealer requires only one hour to set in conditions ranging from 32 to 130 degrees Fahrenheit. Unlike many concrete repair materials, Tigerthane 220 will not become brittle and separate itself from concrete slabs as joints expand and contract.
Garon Products Inc.
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Two high-traffic systems floor coatings, Eco-HTS and VOC-HTS, are made from moisture-cure urethanes to offer 50% more wear resistance than standard urethanes, according to the supplier. The coatings provide a satin finish that resists dulling in traffic aisles. Both HTS coatings comply with volatile organic compound (VOC) regulations.
Tennant
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Durable and impermeable, the FDT Topping Dewatered Traprock provides an impact-resistant and light-reflective wear surface without the use of a sealer or epoxy. To create the floor, all process materials are optimized to formulate a Traprock topping mix-design with a higher than normal coarse aggregate and cement content. The topping is placed over the base slab at a high slump so that every void is filled ensuring proper consolidation and bonding.
Frick Floor Systems
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Repair spalled joints, cracks and gouges in 30 minutes using Spal-Pro 2000, a two-component polyurea polymer liquid of 100% solids content. The material can withstand moderate traffic loads after 15 minutes of curing and heavy traffic loads after 30 minutes of curing. Spal-Pro 2000 is available in 50-gallon drums, 5-gallon pails and dual-cartridge kits.
Metzger/McGuire
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