Is Waterproof Flooring All Wet?

By John Taylor

Living in the Sunshine State, the weather can be a huge problem for our homes. Frequent heavy rains, hurricanes, tropical storms and humidity wreak havoc on our homes, especially our floors. Over the past several years, many homeowners have turned to waterproof flooring, hoping to avoid moisture's mess. However, waterproof flooring doesn’t always live up to its namesake. Moisture-related flooring failures across the country continue to cost contractors, businesses, and homeowners an incredible $2.4 billion per year in remediation and repairs.

Sure, waterproof flooring works great if something is spilled on the floor’s surface, but what if the moisture comes from beneath? If a waterproof flooring product is installed over a concrete slab, there may be a significant amount of moisture in the substrate. Water is one of concrete’s most essential ingredients. It is what makes the material strong and durable. When the concrete begins to dry after being poured – a process that can take months – the water evaporates from the slab’s surface. This drying process ends up trapping some moisture deep down in the slab. A concrete slab that looks dry on the surface could be holding moisture inside.

Family enjoying fun time on a waterproof floor

The water trapped in the slab will rise to the surface and evaporate over time – only it can’t because it is now trapped under the waterproof flooring. The moisture then causes the flooring to fail, which leads to cupping, mold, mildew and other disastrous issues. These issues can be avoided. Before having your waterproof flooring installed, be sure to have moisture testing done on the concrete. Installation instructions from any reputable flooring manufacturer should state that this takes place.

The instructions may read something like this:

All concrete slabs must be checked for moisture before installing material. Moisture emissions from the subfloor cannot exceed three pounds per 1,000 square feet per 24 hours as measured with the calcium chloride test or in excess of 75% in-situ relative humidity. Responsibility for determining if the concrete is dry enough for installation of the flooring lies with the owner and installer.

Once moisture testing is done and the slab is determined to be moisture-free, it’s okay to lay down the floor, right? Not quite. Even if the slab tests moisture-free today, the conditions of the slab may change tomorrow.

Here’s what you should consider before laying down the flooring:

Vapor Barriers and Underlayment – Concrete can absorb and release moisture over time based on changes in humidity and temperature. Even if it’s dry now, it may not stay that way. Most flooring manufacturers require a vapor barrier or underlayment to protect against future moisture intrusion.
Manufacturer Requirements – Every flooring type (vinyl, laminate, engineered hardwood, etc.) has specific installation instructions. Skipping steps like vapor barriers or recommended adhesives can void warranties.

Surface Preparation – The slab needs to be clean, flat and free of cracks, adhesives or debris. Even small imperfections can cause flooring issues later.

Local Conditions – In places like Florida, where humidity is high and groundwater levels fluctuate, even a “dry” slab can draw in moisture later. Preventive measures are vital to prolong the life of any type of flooring.

Moisture testing is just the first step in protecting your floors. To ensure lasting performance and prevent costly damage, follow manufacturer guidelines and use a vapor barrier or underlayment. A little extra precaution today can save major headaches and expenses down the road. Still got questions? We're here to help at Taylor Carpet One Floor & Home!