Surface Preparation And The Risk You’re Not Addressing

Picture this: You’ve spent hours, maybe even days, ensuring a floor surface is immaculately prepared. Everything seems perfect, but a few months later, you’re summoned back to the site to address flooring issues.

The culprit? Moisture lurks beneath the surface, a silent destroyer you might’ve overlooked. In surface preparation, focusing only on the visible top layer can be costly. Digging deeper, literally and figuratively, to assess the moisture condition of the subfloor can be a game-changer in your flooring projects.

To achieve a durable, beautiful floor, make sure your prep work always includes a proper assessment of the moisture condition of the subfloor.

Join us as we delve into why it’s essential to peek beneath the surface, the risks of missing out on this vital step, and how Wagner Meters’ latest technology can be your safeguard against unforeseen moisture disasters.

Buckle up, because we’re about to dive deep into the underbelly of surface preparation!

• How does your surface prep take care of excess moisture in the concrete substrate?
• Moisture Testing is Surface Preparation
• The Ripple Effect of Moisture Damage
• An Ounce of Prevention
• It’s not “One Size Fits All”

Surface preparation is key to laying down a durable, beautiful floor. It’s easy to want to rush through the surface preparation phase. All general contractors and building owners want the floor installed quickly, but speeding through surface prep is a trade-off. You’d take short-term time savings at the long-term risk of flooring failures.

That’s why one of the biggest mistakes you can make in surface preparation is focusing only on the surface.

You already do many essential steps to create the right concrete surface profile for your tile assembly: filling in cracks; cleaning away dirt, dust, chips, and other material remnants that create an uneven surface; and removing any surface obstruction that could impact bonding.

But what about what’s lurking below the surface?

There is always moisture in the concrete slab. If the concrete is new, it may not have had enough time to cure and dry. If the concrete is old, some of the damage you cleaned away could have been a sign of a bigger issue: excess moisture. Signs like salt deposits or efflorescence could all be due to moisture issues.

How does your surface prep take care of excess moisture in the concrete substrate?

Concrete holds most of its moisture below the surface, and that’s the moisture that can kill your work. The only concrete moisture test that gets below the surface is an in-situ relative humidity (RH) test. Consequently, measuring the concrete moisture below the substrate surface with an RH test must be part of your surface prep routine.

This excess moisture evaporates over time from the surface of the concrete. That’s why a surface moisture test can’t tell you the real moisture condition of the concrete. It only tests the surface and ignores all moisture waiting to evaporate over time.

When preparing for a tile floor installation, one of the biggest mistakes you can make is to focus only on the surface.

When the floor covering goes down, the moisture moves upwards and gets trapped under the low permeable finish installed on the surface.

Concrete moisture contains alkaline salts. With tile, these salts can potentially transfer to the surface through grout lines causing unsightly issues. Additionally, with the increased usage of large format tiles with smaller grout lines, there is less area for excess moisture to escape, potentially getting trapped and causing issues to the entire system.

At times, these effects are more than ugly. They can be dangerous. And they might not show up until months after the installation. That’s when you’ll be called back in to fix it all—at your expense.

Moisture Testing is Surface Preparation

The moisture condition of concrete isn’t something you can eyeball, though. Wouldn’t that be nice?

You can’t wait a designated amount of time and then be certain the moisture RH is low enough. No, instead, the only way you can know whether your materials’ moisture condition is in the right RH range is if you measure it.

Independent Floor Testing & Inspection (IFTI) lists the top causes of flooring failure, and one is the application of flooring to a concrete subfloor with too much moisture.

IFTI states that “The only solution to this issue is to invest in adequate concrete moisture testing before applying flooring to the substrate. This allows your team to understand the risks of moisture-related failures, and make a plan to navigate around them.”

If you worry only about surface moisture, you’re missing the bigger picture. The moisture isn’t evenly distributed in unsealed concrete. Most of the moisture is held deep in the slab. This deep moisture below the surface slowly seeps upwards and gets trapped below your installation. If you only measure the moisture condition on the surface of the concrete, you miss all the moisture waiting underneath it.

The only concrete moisture test that tells you the moisture condition within the concrete is an in-situ RH test. Surface-based moisture tests only tell you what moisture is present on the surface. They can’t tell you anything about how much moisture is below.

Use an in-situ RH test to measure moisture deep within the concrete floor slab.

To do a thorough surface prep, you must know the concrete’s moisture condition below the surface. It’s the only way to know whether the moisture condition is appropriate for properly installing your tile project.

An RH sensor, like the Wagner Meters Rapid RH® L6, is inserted into the concrete to test the moisture condition below the surface. Only the RH test has been scientifically proven to measure concrete moisture accurately. An RH moisture test gives you the information you need to ensure that the concrete meets the moisture tolerance of your products.

The Ripple Effect of Moisture Damage

The repercussions extend beyond visible flaws when moisture enters from below the surface.

Excess moisture can:

• Compromise Structural Integrity: Prolonged exposure to moisture can cause materials to degrade faster, potentially leading to structural weaknesses in extreme cases.
• Promote Mold Growth: Damp environments are a breeding ground for mold and bacteria. Mold growth compromises the aesthetics of your flooring and poses health risks to the building’s occupants.
• Escalate Costs: Fixing moisture-induced flooring failures isn’t just about repairing the damaged surface. It might mean reevaluating the entire flooring structure, making rectification much more costly than a simple repair. The indirect costs—like reputational damage and potential legal issues—can be significant.

An Ounce of Prevention

With the evolution of technology and practices in the flooring industry, there’s always something new to learn. Continuous professional development can help you stay ahead:

• Workshops & Webinars: Consider participating in training sessions by industry leaders like Wagner Meters. They often host insightful events focused on the latest technologies and best practices in moisture detection.
• Stay Connected with Peers: Join forums, online communities, or local groups where professionals discuss challenges and share insights. Learning from others’ experiences can save you from potential pitfalls.
• Invest in Quality Tools: While it might seem tempting to cut corners when purchasing testing equipment, remember that a one-time investment in high-quality tools, like the Wagner Meters Rapid RH® L6, can save you substantial amounts in potential repairs and rework.

It’s not “One Size Fits All”

Each project is different.

The conditions of the concrete are unique. The exact tile assembly is unique. And since you can’t base one project off another, moisture testing is essential to your surface preparation. You don’t want to find out months after installation that you have a failure because of excess moisture. How frustrating would that be?

Learn more about how you can protect your next job with the Wagner Meters Rapid RH® L6—a fast, simple, and cost-effective RH test. It gives you reliable, accurate results and the confidence to know when it’s time to move from preparation to installation.

Jason Spangler

Jason has 20+ years’ experience in sales and sales management in a spectrum of industries and has successfully launched a variety of products to the market, including the original Rapid RH® concrete moisture tests. He currently works with Wagner Meters as our Rapid RH® product sales manager.

Last updated on August 31st, 2023