Installation Q&A

Unique insight into common issues and concerns

By Christopher Capobianco

I field a lot of questions from readers of my columns, people who find me on the internet, architects, dealers and installers that I meet in my travels. Here are a few I thought would be of interest. If you have more questions, please let me hear from you. I’ll get the answer and run it in a future Q&A column.

Q: I keep hearing about concrete moisture problems but I have never had a problem and I never test. What’s the big deal?

A: You have been very lucky. Moisture problems are still causing millions if not billons of dollars worth of problems a year. The products we deal with have changed, even over the past 10 years or so. There are more different types of resilient flooring than ever, a lot more wood flooring being used, and carpet backings are more impervious. These are all potential situations where moisture and elevated pH can cause problems.

On the concrete side, buildings are being built faster and lightweight concrete is more popular; both reasons concrete has less time to dry. Vapour retarders under old slabs may be breaking down, and changing weather patterns and population shifts mean more slabs are being affected by moisture from the ground. This is all good information but it really doesn’t matter what the cause is.

The good news is we have an industry standard (ASTM F 710) that says “all concrete slabs shall be tested for moisture regardless of age or grade level,” and every flooring and adhesive manufacturer says so, too. Testing equipment is more accurate and easy to use than ever, so there is no excuse. You should be testing, and charging to do so!

Q: The architect specified plywood underlayment over concrete for a resilient floor project. I read your column warning against doing that. What’s the problem?

A: The concern is that any moisture emissions from the concrete may cause the plywood to swell. Even a small amount of swelling may cause the joints and the fasteners to telegraph through the resilient flooring. Many resilient manufacturers recommend against this practice.

Q: I am buying a 50-year-old building and I am concerned about the floor tile. It’s 12 inches by 12 inches and looks like the type I see in supermarkets. Someone warned me about asbestos tile but someone else said only nine-inch by nine-inch tile had asbestos. What’s the story?

A: Prior to 1992, many resilient flooring products — including nine-inch by nine-inch and 12-inch by 12-inch tile, sheet goods and even adhesive — may have contained asbestos. Have the material and adhesive tested to be sure.

Q: I have a luxury vinyl plank floor that is gapping. What ASTM standards apply to these products? Is it shrinking tile or an installation-related failure?

A: First, get the terminology right. “Luxury Vinyl Tile” (LVT) is not a separate category; it’s a marketing term that is being applied to a variety of materials these days. In fact, there are only two ASTM specifications in the category of vinyl tile; F 1066 Vinyl Composition Floor Tile (VCT) and F 1700 Solid Vinyl Floor Tile (SVT). Is yours VCT or SVT? You can find the answer to that question (hopefully) in the manufacturer’s literature.The gaps can be caused by shrinkage, but to make this claim, you really have to be sure the project was installed “by the book” with the right adhesive, site conditions, acclimation and so on. If everything is right and the tile has gaps, it could be a manufacturing problem, which laboratory testing for dimensional stability can detect. Otherwise, other factors may account for the gapping, such as temperature at the time of year, adhesive being used, or concrete issues.

Q: What is “cork-rubber” tile? Is it the same as rubber-cork? Is it installed like cork or like rubber?

A: There are a number of products that mix rubber and cork to get a unique look and to make it a “greener” material because cork is a rapidly renewable and recycled material. Very confusing marketing terms are being used, like products claiming to be 60 percent cork, which is true when calculated by the overall volume but, by weight, they are less than 10 percent cork because cork is lighter than rubber.

Specifications for “sustainable” materials usually use weight as a calculation for recycled or rapidly renewable content, so that 60 percent number is deceiving. The proper term should be Rubber-Cork, because the product is rubber flooring with cork in it, not the other way around. For installers, think rubber, not cork. It’s installed like a rubber floor, usually with a wet-set adhesive.

Q: What do I need to know about installing “PVC Free” flooring that looks like SVT but isn’t?

A: Vinyl flooring uses PVC (polyvinyl chloride) as the binder and new products are using polyolefin, polyester, and other polymers that are being sold as “greener” than PVC despite the fact that most are still petrochemical based materials. The problem for installers is that these new products can be harder to bond to a substrate, so adhesive selection is critical. Go 100 percent by the book and don’t be tempted to use a VCT or multi-purpose adhesive to save a few dollars. There have been a large number of cases where “PVC Free” floors just don’t stick.

Q: What kind of floor patch should I use?

A: There is an industry standard, ASTM F 710, which addresses this question by stating: “Patching or underlayment compound shall be moisture-, mildew-, and alkali-resistant, and, for commercial installations, shall provide a minimum of 3,000 psi compressive strength.”

Regardless of whether you use a gypsum- or cement-based patch, or poured underlayment, this guideline is very helpful in deciding which product is appropriate for the specific project you are working on. The flooring manufacturer can be very helpful as well, so don’t be afraid to make a phone call for guidance on what to use, especially in high traffic areas. Some flooring manufacturers may have very specific recommendations, so make that call.

Christopher Capobianco is a flooring expert currently with Spartan Surfaces, a distributor of commercial hard surface flooring. Chris’s family lineage in floorcovering goes back for generations. His career includes time as a retailer, architectural sales rep, technical support manager, consultant, instructor, columnist and active volunteer in several organizations.

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