William Thornton – Flooring Confidential: The Underbelly of Cradle to Grave from Manufacture to Installation & Use!

Air Date: 3-20-2020|Episode 578

This week’s show in the Moisture Mob series is with one of the Flooring Industry leading experts based in the Atlanta Georgia metro area. William Thornton is the North American Technical Manager for Tarkett Sports. Originally from the Kansas City metro area where William made his bones in the flooring industry, his career has spanned almost four decades in all aspects of the industry from installation, manufacturing, specifications, consumer complaint handling, technical training to standards writing for industry installation guides.

This week will focus on the indoor air quality aspect of flooring in the built environment from the off gassing of VOC’s in materials and adhesives to the impact trapped moisture creates when improper moisture measurement are not done prior to installations.

How do these issues affect the product user, building occupants and why is it important to understand best practices when specifying flooring materials, installation guidelines and making warranty claims which impact purchasing decisions based on the intended use and application.

The Restoration industry traces its roots to flooring from the early days of drying wet carpet on site to today’s sophisticated methods for drying saturated concrete. Floors get affected on just about every water intrusion event based on the simple principle of gravity and water flows down to horizontal surfaces.

Understanding how floors are installed, affected by moisture and the manufacturing warranties for a product’s specifications are an important aspect of IAQ consultants, restoration contractors and remediation specialists when assessing damage or investigating IEQ complaints.

Join Radio Joe, the Z-man and the Restoration Global Watchdog this week for a unique Moisture Mob interview exploring the underbelly of Flooring Confidential, with industry expert and unique personality William Thornton! LEARN MORE this week on IAQradio+.

Z-Man’g Blog:

Flooring Confidential

William Thornton is North American Technical Director for Tarkett Sports and a leading floor covering industry expert. William has 4 decades of experience in all aspects of the industry from: retail sales, installation, cleaning, manufacturing, specifying, consumer complaint handling, technical training and standards writing.

William is the 4th in the Moisture Mob Series

Nuggets mined from today’s episode:

Architects are involved in a building from everything under roof to what’s below the concrete. Architects must rely upon standards and manufacturer specifications. Flooring contractors must understand the specifications. There are means of communications throughout the bidding, submittal, and pre-installation processes to help ensure clarity and reduce the potential for mistakes. Mistakes do happen, however, despite this.

Odors. In the past buildings weren’t tight. We now know more about flooring materials and adhesives. Historically solvent based adhesives were used which weren’t the best for IEQ. Waterborne finishes are available for hardwood floors. When you buy a new car, it comes with the new car smell which is a combination of off-gassing of the leather and other materials. Latent odors after flooring installation while they may be noticeable aren’t necessarily dangerous. Running the HVAC usually resolves concern. Due to improvements in products, it’s now super rare for him to receive an odor complaint.

Regulatory.Flooring products are manufactured to meet national and internationals  regulations, LEED (USGBC), REACH (Registration, Evaluation, Authorization and Restriction of Chemicals). The majority of manufacturers that are engaged with national/international regulatory requirements for  compliance, are making some of the safest products available. .

Performance of green products. Today’s manufacturers must be environmentally conscious in order to succeed. This is where R&D comes into play. Old flooring adhesives that contain asbestos were functional and durable; and a problem to remove. Where regulations and social responsibility meet chemistry and science.Customers today demand environmentally sound materials without the compromise of exceptional performance.  Technological advancements today accomplish both needs.

Warrantees. Today’s flooring products are superior and the warrantees on them are commensurate with the improved quality.

Acclimation-climatization of flooring products is super important. There’s always a rush during new construction. In an ideal world, fully acclimated flooring would be dropped off to the jobsite for immediate installation. Unfortunately, in the real world this doesn’t happen and flooring problems occur. All flooring products have technical tolerances, there is no buffer in technical tolerances. Wood flooring products require the most time for climatization and engineered wood products less time. Big temperature and humidity swings aren’t good for buildings or flooring products. Stability of the environment, the building and the flooring product are all important. General contractor pushes the flooring contractor to hurry and compromises are often made. It is important to understand that not only are stable and predictable indoor environments are needed conditions for installations, but also very important for the overall health of the building and the occupants within.

Breaking the cycle of blame.When flooring problems occur on a project: the flooring contractor blames the manufacturer, the architect blames the manufacturer, the manufacturer and general contractor blame the flooring contractor. And everyone throws someone else under the bus. The cycle of blame can be broken by having control of the construction site. Understanding specifications. Conducting forensic analysis before installation. The majority of complaints are caused by misunderstanding of conditions on site or the flooring system in connection to those conditions

The chemistry of adhesives has improved. “Old salt” installers still opine that the old black adhesive was stronger and better. Proud of the progress the flooring industry has made over the last decade in developing functional and environmentally compliant products that can offer long term performance

Moisture content testing is important.

Kentile recommended a calcium chloride test in the early 1960s. Before that, a tablespoon of table salt was placed on the concrete and plumber’s putty was used to cover the salt with a drinking glass with an airtight seal. Clumpy salt indicated a moisture problem. Mat test of covering the floor with poly film and tape and observe for visual condensation.

Some adhesives have RH-in-situ requirements of 99 to 100%.  The latter may no longer require RH-in-situ testing. My estimations are that up to 50% of projects  aren’t tested. Also, up to 50% of tests that are done aren’t done correctly. When no pretesting is done the flooring is done at your risk. The best current technology uses an insitu probe ASTM F-2170.The market dictates testing. Technology is advancing and test methods are getting better. Different test methods don’t correlate. In these cases when 2 different test methods are used, the user may choose to rely upon the results that best suit their purpose which is an incorrect presumption More people are testing now than ever before. It’s become harder for contractors to do testing due to time constraints and complexity. Resulting in more reliance on specialty meters. The market demands quicker, easier, faster testing that the industry can do (e.g.: simultaneous testing body of concrete and surface of slab).

MVRA (moisture vapor reduction additives) additives and pH of concrete complicate testing.

Foreign versus domestic products. We all remember the Lumber Liquidators issue. The best flooring products come from Europe and the US. These products meet LEED, REACH, CA Prop 65, CARB, TSCA, etc. Some roducts which don’t meet these standards may be inferior. Just because it is “foreign” made, doesn’t mean the material is necessarily bad.  This is where meeting encouraging environmental initiatives is important.

When concrete is ready for flooring depends on the type of adhesive being used (adhesive types include: hard set, pressure sensitive, reactive and single component) ASTM 710 provides guidance.

Education. Most flooring manufacturers provide training to installation contractors, William’s course includes ASTM 710, floor patching, moisture mitigation, adhesives, types of floors, regulations, etc.

Moisture mitigation methods include: environmental control, saw cuts, hand trowel finish with sealer. Dehumidifiers can over dry concrete and cause it to curl which is caused by a disparity of drying between top of slab and bottom.

Pre-installation bond tests are important and flooring contractors are resistant to doing them because they take time. William cautions that “flooring contractors need to understand the nature of things” that they are getting into.

  • “Sealers, Curing and Parting Compounds: Tarkett does not recommend the use of concrete sealers, curing and parting compounds. These materials may not be compatible with Tarkett adhesives and may interfere with the adhesion of the flooring material. These products shall be removed using a terrazzo grinding machine or by sanding with a drum sander. A bond test shall be performed to determine if adhesion properties are acceptable. Bond Test A bond test shall be performed on all grade levels to determine if the concrete is sufficiently dry and if a sealer, curing or parting compound was used. Install a few pieces of the flooring material selected for the installation and adhere with the recommended Tarkett adhesive. Pay particular attention to the adhesive open time. If after 72 hours a significant amount of force is required to remove the flooring from the concrete, and there is adhesive transfer to both the concrete and to the back of the flooring, the bond can be considered satisfactory. NOTE: Regardless of the bond test or the type of surface treatment used, the responsibility for warranties, guarantees, and performance of a concrete substrate on which a surface treatment has been applied rests with the manufacturer of the surface treatment product for adhesion and/or patching compound failures and not with Tarkett. Floor Flatness: The surface flatness or levelness will affect the finished appearance of floor coverings. Installation of flooring products over an excessively uneven or undulating concrete slab will require working techniques on the part of the installation contractor that would include leveling and smoothing. It is recommended that both flatness and levelness requirements be described by Face Floor Profile Numbers (F-numbers). Refer to the American Concrete Institute ACI 302.1 Guide for Concrete Floor and Slab Construction. 5 Painted Floors Tarkett does not recommend installation of Tarkett flooring products over painted surfaces. All paint shall be removed from the surface to be covered.”

Fuzzy side up– William’s craziest flooring claim was when a flooring installer installed cushion flooring upside down.

What are CSP Ratings?
“For proper bonding of overlays and coatings, it is important that a concrete surface have the correct Concrete Surface Profile or CSP. A CSP rating is a standardized rating that allows you to visually determine the concrete surface roughness.
The most important step in creating a quality floor is the preparation. And for the proper bonding of any coating or overlay, you need to properly prepare the floor with the proper concrete surface profile. But what is a concrete surface profile? A concrete surface profile, known as a CSP, is a standardized measure for the ‘roughness’ of a surface that is defined by the International Concrete Repair Institute (ICRI). A very rough surface will have a high CSP number, such as CSP 9. A very smooth surface with almost no preparation at all will be a CSP 1.

This rating can be achieved with our tooling that carries a 30-40 Grit rating.
For coating applications from 4–5 mil thickness, the surface profile should be a CSP 3.”  https://www.werkmaster.com/concrete-profiling/

Planetary Grinders

“The base of the planetary grinder is set up with one large main disc with three smaller discs mounted to the larger disc. The smaller discs rotate at a different rate of speed than the large disc. The smaller discs are all in the same plane, so they all are in contact with the floor at the same time. The larger disc is not in the same plane so it does not make contact with the floor.

Planetary grinders are typically lighter weight than rotary grinders, this makes them easier to maneuver. They are made to move across the floor in a straight line pretty easily, which puts a lot less stress on the operator. Due to the lightweight build of the planetary grinders they work a lot better on not very aggressive jobs like smoothing down a concrete floor or preparing a floor for an epoxy coating or overlay. Planetary grinders can also be used for polishing concrete, but it is suggested that a more experienced operator use it for this type of work.” https://www.polishtheplanet.com/blog/article/rotary-vs.-planetary-grinders-whats-the-difference

Shot blasting is a process that is normally done on concrete or metal surfaces. Steel beads are “shot” out of a machine at a very high velocity. The beads “blast” off debris and stains that are on the floor which can’t be removed through regular cleaning methods. Our method of shot blasting involves little cleanup; all of our machines have built in vacuums that collect the dust and the shot.”  https://shotblastinc.com/concrete-resurfacing/shot-blasting/

Concrete scouring compound

Planiprep SA Planiprep SA – Mapei

www.mapei.com › public › products › 3004070-planiprep-sa-en

Apr 5, 2019 – Planiprep SA is a powerful, acidic scouring solution designed for preparing nonporous or chemically contaminated concrete surfaces. This product will chemically etch the surface of concrete to create a scoured, porous surface, promoting excellent adhesion for the subsequent application of adhesives or Planiprep ET.


Restoration Industry Global Watchdog, Pete Consigli

  • William Thornton, Bob Higgins and Andrew Rynhart (in collaboration with restoration and flooring contractors) are working to establish criteria for moisture measurement of concrete.
  • Water damage restoration is rooted in the flooring industry. Coming back from its roots to work together to improve communication for the good of their customers.
  • Not all moisture measurement instrumentation is the same, the industry needs better training on the use and application of different types of meters and probes used to determine moisture content in materials!

William Thornton, final comment

The Moisture Mob is the meeting of minds between restoration and flooring industries. He’s proud to be part of the group and confident that the flooring industry and consumers will benefit from it.

Afterthought: The general contracting and flooring industry can learn from working with the restoration industry to ensure concrete and other materials are dry before installation of flooring and move-in of the building occupants.

Text Chat Nuggets:

From Clayton Shull to Everyone:  12:29 PM

Hardwood is based on moisture content levels of the product and the subfloor.

Environmental conditions should be what would be typical when the building is finally in use.

Some adhesives have RH-in-situ requirements of 99 to 100%.  The latter may no longer require RH-in-situ testing.

Some dry tape adhesive require no moisture testing.

Example, Nora Drifix 750

andrewtramex to Everyone:  12:34 PM

100% vapour as per F2170 is not anywhere near 100% moisture (it’s usually closer to 5% moisture). Problem with stating 99% or 100% is people mix them up causing other moisture issues in buildings.

From Clayton Shull to Everyone:  12:46 PM

It is critical that the Flooring Contractor perform multiple bond tests!!!!!!!!!!!!

From Don.Weekes to Everyone:  12:49 PM

Registration, Evaluation, Authorisation and Restriction of Chemicals (REACH)

From andrewtramex to Everyone:  12:52 PM

Most building sites are not at “in service” condition, therefore using dehumidification heat and air is ideal for getting the space into the ideal condition for drying.

Z-Man signing off

Trivia Question:

Name the flooring material which dominates indoor sports flooring in the US?


Maple hardwood

Clayton Shull. All Flooring Inspector, British Columbia, Canada