Adequate preparation of concrete includes moisture testing and a light sanding, as shown here.

First, a big thanks for all of the feedback on the last "mailbag" column, which looked at questions concerning residential resilient flooring. Answering your questions helped me recall many fond memories from my 15 years in the residential side of the business. Now, having spent nearly 14 years on the commercial side, there are a number of questions that often come up. Whether it is in the seminars I conduct, people calling with questions from the field, or the emails sent by NFT readers, there is clearly a need for more information on commercial. Here, then, are a few questions I have heard lately. If there is something else you want to know about resilient flooring (commercial or residential) feel free to contact me.

Flooring and adhesive manufacturers seem eager to blame installation failures on concrete moisture problems. Is this legit? Or it just that adhesives are not as good as they once were? I don't remember having these problems 20 years ago.

A: Whoa! That's a column all by itself, or an entire book! In a nutshell, the answer is yes and no. There is an epidemic of concrete moisture-related flooring failures today - and it's not just happening in resilient. Wood, laminate, carpet and even some stone products are susceptible to failure from moisture and the elevated pH that comes with it. There is some disagreement about whether today's water-based adhesives are more moisture sensitive and whether the old products like Vinyl Asbestos Tile were less sensitive than today's resilient floors. There are also more "high performance" resilient floors like solid vinyl, rubber and unbacked sheet goods being sold today so this can be an issue. But there are also several reasons why the concrete we work with today may be wetter than in the past including fast track construction practices, old factory and warehouse buildings being converted into finished space, and buildings being constructed on substandard land due to a shortage of "good land."

Here's a simple rule to keep in mind: If it's concrete, it must be tested! This applies to concrete in the basement or on the 50th floor, whether the building is brand new or 50 years old. Looking at it, smelling it or touching it tells you nothing about the invisible water vapor that may be migrating out of that concrete slab. If you have never tested and have never experienced a moisture-related failure, then consider yourself very lucky.

Designers seem to be specifying more exotic resilient flooring materials like solid vinyl, linoleum, cork and rubber, as opposed to Vinyl Composition Tile (VCT). What do I need to know before I bid on these jobs?

A: If you have the opportunity to work with the designer directly, don't be afraid to speak up and make sure the flooring being specified is appropriate for the use. For example, a smooth, high gloss, darkly colored resilient flooring product like solid vinyl tile should not be installed unless the word "buffing" is part of the maintenance vocabulary. Assuming the product is appropriate, sit down with your installer and the installation instructions to be sure there is a clear understanding of the procedures needed and time required. Don't be afraid to call the manufacturer's technical department to clear up any questions. I have seen so many problems on jobs because of what I call the "VCT Mentality." Most products other than VCT take more time to install. That needs to be figured into your bid. Don't be afraid to pass on the bid if your installation team is not familiar with the product.

I keep hearing the terms "Luxury Vinyl Tile (LVT),""Solid Vinyl Tile (VCT)" "Vinyl Enhanced Tile (VET)" and "Premium VCT." What's the difference between these products and how do they compare to Standard VCT?

A: The industry standards for resilient flooring products are the ASTM Standard Specifications and there are only two for vinyl tile: ASTM F 1066 for Vinyl Composition Floor Tile (VCT) and ASTM F 1700 for Solid Vinyl Floor Tile (SVT).

Premium VCT is an upgrade from standard VCT. It may have more authentic patterns such as granite looks or may be available in solid colors. As far as VET and other "higher vinyl content" VCT products, all of these are classified as VCT. The higher vinyl content often allows for larger sizes, improved visuals, easier maintenance and better indentation resistance. Check the installation specs, because these products usually don't get installed with standard VCT adhesive so there may be a higher cost for adhesive and labor.

Solid Vinyl, or SVT, has higher vinyl content than VCT and consists of three categories: Class 1 Monolithic (through color), Class 2 Surface Decorated (through color wear layer on a backing) and Class 3 Printed Film, which has a clear wearlayer. These products have better visuals and better performance than VCT.

The term "Luxury Vinyl" has created unnecessary confusion in the industry. The fact is there is not an industry standard for LVT. The SVT Class 3 products that imitate wood, stone and other materials are often called LVT. However, there are also products marketed as LVT that are residential grade and don't have enough vinyl content to be called SVT. So, "Luxury Vinyl" can be SVT or VCT. The manufacturers would do the industry a favor by clarifying this difference in their marketing and sampling.

Cork seems to be growing in popularity. What advice do you have for working with this product?

A. I have worked for two different cork companies and one of the seminars I do regularly is called "The Fascinating World of Cork." There is a lot to this product, but I'll give a quick snapshot with five keys to cork flooring.

First, specify the right products. Homogeneous cork is "through color" and can be sanded and refinished like a wood floor. Veneer cork cannot, so there is a definite difference in the lifespan of these two products. Second, cork is being produced in glue down tiles or as a floating floor. Since most of the floating products are veneer, they need to be used carefully in commercial settings, if at all. Third, cork is being sold with three different types of finishes. Unfinished can be stained and finished on the job so it is great for companies with "sand and finish" experience in wood floors. The factory urethane products come prefinished, but it is a good idea to add another coat of urethane or two after the floor is installed. The waxed tiles are the more traditional cork floors and have a beautiful low luster look. However, they are more difficult to maintain because they need to be waxed regularly, as in real paste wax and a buffing machine.

Fourth, it is absolutely critical that you acclimate the product on the job site and make sure the substrate is smooth and dry because cork is sensitive to temperature and moisture. Finally, there are two different adhesive choices for cork. Contact adhesive is applied to the tile and to the floor with a paint roller, and has an incredibly strong bond. Trowelable adhesives are perhaps a bit more installer friendly, but open time is critical. If the adhesive is left open too long, there will not be enough bond strength to prevent the tile from curling if it is so inclined...

I hope that is of some help. To be honest, I could easily have written an entire column on each of these questions. There is so much more to say. (I'd say we only scratched the surface, but as a dedicated flooring guy, that's the last thing I ever want to do.) If you have a question or a subject related to resilient flooring that you'd like me to cover in the future, please send me an e-mail.