Contemporary moisture mitigation treatments coincide with increased expectations for accelerated construction timelines. Moisture mitigation, as commonly used in the industry, is usually a reactionary measure for overly moist concrete slabs. Because concrete placement and drying constitute a significant chunk of a facility’s construction timeline, developers rush to accelerate the process through methods that can potentially compromise the health of a project.
As the term “moisture mitigation” implies, the mitigation of moisture is simply the mitigation of risk, not necessarily an elimination of the root problem. Furthermore, moisture mitigation as a “quick fix” nevertheless takes time to install and delays the installation of flooring — sometimes significantly. There are various methodologies and philosophies regarding proper moisture mitigation, many of which are far less effective than others.
Rapid-drying concrete, meanwhile, eliminates excess moisture (known as “water of convenience”) throughout the drying phase. Compared to conventional concrete, rapid-drying concrete cuts water vapor pressure (the primary cause of flooring issues) in slabs by two-thirds. Tests on rapid-drying concrete show target relative humidity levels (RH) are reached 45 days, a far cry from the potential 100+ day drying times of conventional concrete.
Breaking Down the Risks of Moisture Mitigation Methods
The reactionary nature of moisture mitigation in itself increases the risk of future moisture-related flooring problems. If a concrete slab retains too much moisture, many moisture mitigation approaches may not install properly or will eventually deteriorate over time. A reactionary measure of moisture mitigation does not eliminate the moisture in the slab, it only traps it in the slab. This can create moisture vapor issues later down the road. If moisture mitigation is required for any concrete slab, project costs rise as a result of the additional installation.
Still, moisture mitigation can be effective despite methods possessing their respective flaws. Here are some of the risks developers should consider if moisture mitigation is necessary:
- Accelerated Drying — If the natural drying of the slab is not sufficient, drying will be accelerated through temperature and humidity control. Though this method reduces drying time, it remains expensive and works best only if the slab is shotblasted open to release excess moisture.
- Cementitous Overlays — A primer is applied to the surface of a concrete slab before a dense cementitious layer is poured over the top. Within this method, the slab is isolated from the floor covering system. This can be an effective moisture mitigation solution although it doesn’t deal with the primary issue at its source and creates significant delays in the construction timeline.
- Reactive Silicates — A silicate-based treatment reacts with the calcium hydroxide naturally emitted from the concrete. Though this can densify the surface of a slab, its moisture mitigation effectiveness is questionable and flooring manufacturers have been known to refuse warranty when these products are used.
- Moisture Mitigation Coatings — Developers apply acrylics, hybrid epoxies or urethane coatings on the surface of a concrete slab. This is a very labor-intensive and time-consuming topical moisture mitigation treatment, where alkali-silica reactions, near-surface alkali reactions and the development of osmotic cells could deteriorate the coating. The situation is especially volatile if MVER and/or relative humidity is critically high during the application.
Rapid-Drying Concrete as a Solution
Rapid-drying concrete effectively eliminates the need for moisture mitigation methods since concrete slabs quickly reach target moisture levels within a remarkably short timeframe. Its ability to shorten construction timelines while eliminating the need for additional costs make it a lucrative alternative for developers seeking a concrete solution beyond conventional products.
Though moisture mitigation solutions on conventional concrete slabs have been the norm, rapid-drying concrete essentially eliminates the need for additional moisture-related precautions.