Whether it is visible or not, most everyone is aware that concrete is quite prevalent in both residential and commercial construction. Concrete is first poured (or pumped into the building), and then carpets or hard-surface coverings are installed. However, a problem can develop and far more frequently than is often realized—when moisture is released from the concrete. When this happens, carpets glued to the concrete may lose their bonding and begin to look soiled and buckle, VCT adhesive begins to ooze, the flooring may actually lift, and it‟s likely that mold and mildew will grow. Is It Cured and Dried? So many buildings today, both commercial and residential, are built under “fast-track” conditions. Typically, contractors and subcontractors have a limited period of time to complete their part of the construction project. If they fall behind, they can be penalized financially and set the entire project behind schedule. This rush to complete the job is often the core reason we have concrete moisture problems. The building may be completed before the concrete has had a chance to dry and cure. If flooring, whether carpet or hard surface, is applied over concrete that has not properly dried or cured, it can become a problem just waiting to happen. Dry and cured are two different things. A floor may be dry to the touch and the excess moisture used to apply the concrete evaporated, but that does not mean it has cured, which is a chemical reaction that bonds the ingredients with the concrete. In most situations, concrete slabs require a minimum of 28 days to cure under ideal conditions before a floor covering should be installed.

A curing compound can be used to help expedite the curing process, but must be removed before flooring is installed. In most cases, the compound is left on the concrete too long, preventing the moisture from getting out of the slab—the opposite of the application‟s intended effect. Additionally, vapor retarders can be applied, which can help reduce moisture problems. However, in many cases they are left out in the interest of saving money.

Detection and Responsibility Many building professionals incorrectly rule out concrete moisture problems if the floor-covering problems mentioned earlier occur on a higher story in the facility. Although the problem is more common on lower stories, it can occur on any floor. Also, buildings in dry climates, even older buildings that have never had problems in the past, can develop moisture issues. Again, the crux of the problem is not climate or age or on what story the problem is occurring, but whether the concrete was allowed to cure properly. There are various ways to detect a concrete moisture problem, but according to Williams, moisture testing is the only true way to verify the moisture content of a concrete slab. Proper testing of the concrete in the area experiencing moisture problems is required and should have been done in the first place. If moisture testing was done prior to the flooring installation, run new set of tests and compare the results. The goal is to get the meter

reading to the required acceptable levels of the flooring manufacturer.” If a moisture problem is detected, often the flooring contractor is thought to be the guilty party. However, in most cases, the contractor is just following the specifications of the architect, while also meeting the fast-track demands of the general contractor. If moisture problems are suspected, the first thing to do is to discuss the possible solutions with their clients. In most situations, the floor covering will have to be removed, and disposed of. Once the flooring has been removed, air movers and dehumidifiers can be placed at strategic locations throughout the problem area to expedite drying. Additionally, ventilating the area and turning up the heating system to 75 degrees Fahrenheit also will help. Studies have found that using air-conditioning can actually make the problem worse because the cool air can increase condensation on the concrete surface. The flow of air over the concrete, which creates the greatest rates of evaporation, is what‟s most important.

Now, the problem must be determined and the source found. Was the concrete not dry to begin with or did the problem just occur. This is why preliminary moisture testing is important before installing any flooring. Now you have some results to compare to. If it is truly just wet concrete, this will require a moisture retarding system to bring the moisture down to the required levels. If mold or mildew is suspected, an air scrubber may be necessary. More advanced systems have HEPA filters and multistage filtering systems that help capture contaminants, particulates, mold, and fungal spores. For greater mobility, select a machine that has a „dolly design,‟ so even one person can transport the machine. A machine that can be used vertically or horizontally allows greater versatility. Remember, it was likely the rush to complete the facility and flooring installation that caused the concrete moisture problem in the first place. In most cases, it takes about two weeks to ensure that the concrete dries, is cured, and the moisture problem has passed.