Evolution of moisture mitigation in concrete flooring

Preemptive moisture mitigation

Dome over a CaCl test.

Preemptive moisture mitigation has become commonplace in hospital settings because a flooring failure resulting in downtime is far more costly than the price of moisture mitigation as an insurance policy. While this practice is extremely effective, it has not been widely adopted across commercial construction because adding $4 to $7 per square foot to the overall budget is not an option. Instead, contractors install the slab, wait as long as possible to test it and then deal with the problem if testing reveals an issue.

Therefore, moisture mitigation has had to evolve and improve. Owners were shocked to hear fixing their floors would cost more than the finish they had selected for them. Floor prep and flooring manufacturers started releasing products which did not require mitigation or testing. While many of these products work, they do not address the underlying moisture issue, which will remain a necessary consideration for every future flooring change. When it comes to moisture, it is generally accepted across the industry that it is best to fix the problem, thus floor prep manufacturers began exploring more cost-effective moisture mitigation technologies. Sodium silicates hit the scene as a solution for moisture emissions about 10 years ago. Sodium silicates are added to the concrete at the batch plant or onsite as the concrete pour is happening. These products have worked in certain settings, but overall have had mediocre success due to potential bond issues. Many flooring manufacturers do not recommend them underneath products. As such, their warranties generally require the presence of someone onsite to make sure their product is installed properly to prevent a moisture or bond failure.

Single-component mitigation technology

Single-component mitigation technology has been an area of advancement driven by excessive cost associated with the installation of a two-part epoxy moisture mitigation system. While some of these products have proven to perform as well as two-part epoxies, there has been pushback from architects and general contractors who are looking to adhere to ASTM F3010, Standard Practice for Two-Component Resin Based Membrane Forming Moisture Mitigation Systems for Use Under Resilient Floor Coverings. ASTM committees create several different types of documents, such as testing methods or practices for the industry. Standard test methods are procedures that generate test results defined to provide a uniform method for collecting specific data. ASTM F3010 is often perceived as a standard test method, however it is a standard practice, which is a set of instructions that does not generate a test result.

ASTM F3010, however, references ASTM E96, Standard Test Methods for Water Vapor Transmission of Materials. This standard test method is the key to ensuring a system can block moisture vapor emissions, and it is used across a variety of industries to test a broad range of products including moisture mitigation systems, tape, food, and pharmaceutical packaging.

The major advantage of a one-component product is its price advantage. A one-component product can be installed for several dollars less per square foot than a two-part epoxy system. Single-component moisture barriers generally only require an open surface to be installed. Instead of an aggressive CSP three to five, achieved through shotblasting, proper surface preparation can be achieved through the less intensive process of grinding. Single components are installed in two coats. However, the second coat also serves as the primer for the underlayment or flooring, which eliminates the need for an additional primer or sand broadcast. Because a single component is not activated by a chemical reaction as with a two-part epoxy, the installation process is more forgiving.

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