Moisture Mitigation

How Does Moisture Affect Your Floor?

The presence of moisture within a concrete slab is one of the most common causes of adhesive and floor covering failure in the flooring industry today. Tripping hazards, unsightly curling and bubbling and a weak floor surface can all be linked to high moisture. These failures raise questions about the construction process; why does this happen, how can I tell if it is happening to my floor, and how can the issue be solved? In all situations, it’s important to understand what is going on with your floor and to know that no two cases of moisture are the same.

Why Do Moisture Issues Occur?

Simply put, moisture issues occur because of water vapor migration through the concrete substrate.

Unfortunately, there are plenty of slabs on-grade today that do not have protection from the underlying soil in the form of a vapor retarder. Substrates without a properly placed vapor retarder are commonly referred to as “open systems”. Open systems are typically vulnerable to unsuitable levels of vapor emissions that can lead to a floor covering failure.

All concrete contains water and must be allowed to dry properly to avoid issues, however, in the fast-paced industry of construction many developers don’t provide sufficient time for concrete to cure naturally to a level acceptable for the installation of flooring or coating materials. In addition, curing, sealing, or bond-breaking compounds are commonly used in concreate slab construction all of which prevent the release of free moisture from within the slab.

If there is inadequate time for the concrete to dry, the adhesive bond at the surface can be compromised. If a floor covering is installed prematurely, the concrete will continue to emit moisture in the form of vapor as it migrates upward to the surface, bringing with it, soluble salts. The moisture is unable to pass through impervious flooring, (vinyl tile, ceramic, etc.) and remains trapped between the flooring and the concrete slab. Over time, this buildup of moisture and soluble salts attacks the adhesives until the bond is compromised.

How Can I Tell if My Floor is Affected?

Cupping and curling around the edges of tiles, cracking and adhesive failure, are clear visual indicators of distress caused by moisture. These issues are unsightly and can pose a safety risk if corrective measures are not taken immediately.

Moisture and alkalinity testing performed by a certified independent inspector can help determine the severity of the issue. Relative Humidity (RH) testing is performed by placing a sensor into a drilled hole in the concrete at a pre-determined depth to measure deeper levels of moisture. Anhydrous Calcium Chloride(CaCl2) testing is performed using a petri dish covered by a plastic dome which is placed within a previously abraded 20 inch x 20 inch area of the concrete for 60-72 hours, and then weighed to determine the moisture vapor emission rate (MVER) typically found in the top half inch of the concrete.

Both testing methods will yield quantifiable measurements that can be used to determine the severity of the moisture problem and help determine the best solution options. Manufacturers of floor covering materials and adhesives will clearly point out in the material specifications, the limits of their products relative to the readings of either, or many times, both the CaCl2 and RH test methods.

How Can Moisture Issues be Solved?

Once test results have been gathered and analyzed, there are often many solutions. There is an uptick in the use of reactive penetrants recently, with a major difference in when they are applied. In the past, most reactive penetrants were applied after the concrete was placed. Today, they are applied during the pour, ensuring proper penetration be used to reduce the surface porosity and thus reduce the amount of moisture transfer. These are only affective in situations when there is high enough calcium hydroxide (Ca(OH)2) in the concrete to complete the chemical reaction.

Another solution growing in popularity is the use of membranes. Membranes are buffers that sit between the concrete slab and the flooring material. These have become popular due to ease of installation. Coatings have been around longer than any other solution because they have proven effective time and time again. Typically, an epoxy style coating is used requiring the floor to be blasted or grinded. The difficulty with coatings is that they usually can’t be used in an open store/occupied remodel due to dry time. Other, less common solutions include specialty tiles that allow moisture to pass through them, polished concrete, and ceramic tile.

How Can Inside Edge Help You?

First, the solution would be to avoid the issue all together. Calling Inside Edge to install flooring the first time will ensure that it is done right. Moisture/alkalinity testing before the first floor is ever put down will save you thousands of dollars, and a lot of headaches down the road.

If moisture is already an issue, there is no ‘one size fits all’ fix, so Inside Edge takes the time to properly test and evaluate the concrete slab to determine any underlying concerns. Moreover, our experts take the time required to help our customers determine a custom, effective solution that works for your business and your budget.