Solid-vinyl adhesives: Know what you have

By Christopher Capobianco

In my last column, I covered vinyl composition tile (VCT), so I thought this time I’d look at the “other” vinyl tile products and some confusing terminology and often nebulous installation instructions.

Because vinyl composition tile (VCT) has been around for so long, architects, building owners and flooring professionals often go to those products out of familiarity; use what you know. VCT is still about the least-expensive floor to install besides paint, and wears pretty well in a variety of traffic areas. The downside is lack of design options and high cost of maintenance due to the porous nature of the product. It’s inexpensive to install but expensive to maintain, so over the life of the floor it’s really more expensive than other options.

Solid vinyl tile (SVT) has become an increasingly popular design option, and there are a number of different types. The difference between VCT and SVT is that SVT has a higher vinyl or “binder” content. High-content (30 to 34 per cent or higher) products are classified as SVT, and products under that content are VCT. Generally, the higher vinyl content makes the tile more flexible so it’s easier to handle and can be made in larger sizes such shapes as planks, squares and rectangles. There are more realistic and decorative designs than ever, created by printed films. In most cases, it’s also less porous so it’s easier to maintain than VCT, with the most advanced commercial products using a UV-cured polyurethane (PUR) coating so they don’t require any type of floor finishes.

Described in ASTM F1700, Standard specification for Solid Vinyl Floor Tile, there are three types — Class 1 Monolithic (homogeneous), Class 2 Surface-decorated (inlaid) and Class 3 Printed Film (often called luxury vinyl or LVT).

From an installation point of view, the rules are the same for all types of resilient floor tile regarding substrate preparation, testing for moisture and how you lay out the job. Nothing changes from one product to another.

However, with all the different resilient products on the market now, adhesive selection is critical, and this is where I have seen some mistakes made. The misleading term LVT has caused some of these mistakes because so many different types of products are being marketed as “luxury,” and products are flooding the market from all over the world.

Some products marketed as LVT for residential use are actually VCT products with a decorative surface, and other LVTs are true commercial products with a heavy-duty, no-wax PUR wear layer that is state-of-the-art. Most other products are somewhere in-between, although they are not the same, so it’s important to know what you have.

For trowel-applied adhesives, “clear thin spread” is the most commonly used product for VCT. Installers like working with this product because of its long working time – you can put adhesive down over large areas. This is also known as a pressure-sensitive system.

Although some SVT products can be installed with a pressure-sensitive adhesive, it is not the same adhesive product, so don’t be tempted to use VCT adhesive on SVT. I have seen several failures where that happened and the SVT curled and/or shrunk. When the adhesive was tested and found to be the wrong one, the installer was responsible for the complete replacement of the job, and it was a very expensive mistake.

If the job calls for a pressure-sensitive adhesive, make sure you use one that is designed and warranted for the product you are installing. Also, SVT adhesives don’t have as long a working time as those VCT adhesives, so check the instructions and don’t spread too much at once.

For high-traffic commercial spaces, it may be best to stay away from pressure-sensitive adhesives and go with a “wet-set” type acrylic adhesive that has a much stronger bond over the long term. In even more extreme conditions, such two-part reactive adhesives as epoxy or polyurethane work best in areas with high rolling load or point loads, surface moisture or wide temperature variations. Yes, these adhesives are harder to work with but the floor will perform so much better in these cases that it’s really necessary.

Trowel selection is another place where I’ve seen mistakes made with SVT and other resilient flooring. I recommend that for each job, the installer or dealer purchase new trowels appropriate for the adhesive, the substrate and the tile being installed. SVT adhesive will often be applied with a finer notch trowel than the standard VCT or carpet adhesive. And, more is not always better! Too much adhesive can lead to such failures as adhesive oozing, tiles shifting or indentations in the finished floor, so do not fail to pay attention to this detail. A good trowel costs a penny or two per square foot and that is an important investment.

Spray adhesive is an option I have grown to like for SVT products. I have been impressed with how easy and fast it is to use, and how well the tile is held in place with almost no gaps between the tiles and no telegraphing of adhesive trowel marks. You also can move right into the space after the tile is installed with no waiting time for adhesive to dry or cure. A bonus is that spray adhesives offer superior moisture and alkali tolerance and eliminate special adhesive (such as two part epoxy) in areas of high static or dynamic loads because they eliminate indentations from adhesive displacement. Installers have less time on their knees with a spray adhesive but have to adjust their work habits. Making sure that the substrate is clean is key. When using a trowel, small bits of dust and debris get picked up as you spread the adhesive, but not when you spray. Vacuuming or damp-mopping the floor can prepare the substrate properly for a spray adhesive, and on large jobs, a small auto scrubber can be used. The extra work in advance of spraying the adhesive is worth it because the job goes so much faster from that point forward and there is no worry about getting on the floor too soon.

Regardless of which SVT adhesive system you use, it’s important to match the adhesive and the trowel to the product; the substrate and the expected traffic load for the finished floor and quote the job accordingly.

 

Christopher Capobianco is a flooring expert currently working with Forest Hill, Md.-based 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.