It is amazing how many millions of square feet of Vinyl Composition Tile (VCT) are installed throughout North America each year. It is also amazing how much misinformation there is out there about this important flooring product--particularly among end users. VCT provides excellent performance at a value price point; and when properly installed and maintained, VCT construction will provide years of durable wear. It also has a compelling look. Because VCT is typically a modular 12” x 12” product, it will produce an overall monolithic visual either in a calendared or through chip design. Usually VCT is installed in a multitude of design configurations. Being a modular product, end users often expect that the tile lines will not be visible.
Reasonable expectations can vary from person to person so if you are working with VCT it is important that your client (be they the general contractor, the architect or the tenant) understands what this flooring can and cannot do. So, when discussing the visual characteristics remember to keep the following in mind:
• The joints between lighter color tiles will appear as a dark line, especially after a polish has been applied.
• Construction soil will get into the tile joints and when a polish is applied, the polish will accentuate the soil in the tile joint.
• The joints between darker color tiles will appear as lighter lines.
• The joints between tiles in a newly installed floor may appear tighter than the joints of a floor that has been installed for a longer period of time (usually six months or more).
• Often, small spaces between tile joints--“gaps”--may be observed in a VCT installation.
• No installation of VCT will be without tile joint irregularities. No substrate is perfect and installing tile over those irregularities will produce tile runs.
• Slight gaps in a VCT floor will not affect the performance of the floor when the recommended maintenance procedures are followed, as the sealer/polish applied to the floor will fill these gaps, preventing dirt from embedding in the tile joints.
A persistent issue, of course, is unsightly gaps in tile joints. They can have many different causes, and may not be from a single cause, but a combination of causes. Consider these possibilities:
Acclimation of the tile and the environment:The VCT tile was not properly conditioned to the area prior to installation, or the recommended temperature ranges were not maintained during storage and installation of the tile. An example would be if a tile stored in a hot environment were installed in a cooler environment. It’s simple physics: the tiles, expanded from the hotter environment, now return to their manufactured size, leaving gaps between the tiles.
Maintenance too early:This includes wet washing the floor too soon, flooding the floor with too much water during maintenance, or using a no scrub/no rinse stripping solution within two years of the installation. Flooding a VCT floor during maintenance procedures will attack the adhesive bond at the tile edges.
Maintenance too late:Not applying the initial maintenance two coats of polish to protect the tile and prevent dirt from getting trapped in the tile joints from construction traffic.
Traffic too soon:Heavy foot or wheeled traffic on an uncured adhesive and unset tile is a recipe for failure. Not protecting the floor from rolling load traffic such as lift trucks, scissor lifts, dollies and especially ladders will cause tile to spread and twist.
“Off line” installation:Gaps can be formed during the installation of the tile, especially on larger areas, as the installer compensates for irregularities in the substrate and the layout, causing the tile to run “off line.” Many times the tile is considered “out of square” when the real problem is a substrate flatness issue. It is rare for VCT tile to be out of square.
Installer error:Many installers lack the skills necessary for the proper placement of VCT. They don’t know how to correct a tile runoff. They don’t know how to work around substrate irregularities. Some don’t even know how to handle the product itself. It is remarkable how many installers hold VCT by its corner rather than the center of the tile. Holding tile by the corner tends to twist the tile during placement. Right-handed installers holding VCT by the corner will pull VCT tile to the right and left-handed installers to the left.
Wrong adhesive:The use of non-recommended adhesives that are not totally compatible with the plasticizers in the VCT tile. There is no “one-size-fits-all” adhesive.
Improper adhesive application:The trowel notch used to apply the adhesive can be either too large or too small. Using too little adhesive would result in a loss of bond which could result in tile movement. Too much adhesive and the tiles can start slipping or moving toward the space between the tile and the wall, leaving unsightly gaps. An even larger problem is improper notch spacing allowing the trowel notch to show through the installed tile.
Temperature changes:Technically this is known as “thermal coefficient of expansion and contraction.” Simply put: all VCT is affected by temperature changes. The lighter the color the tile, the more movement will be visible. In areas of direct sunlight the temperature of the tile can exceed 150 degrees, causing the tile to expand severely and when allowed to cool, reverting to its manufactured size. Structures like schools where the heat and/or air conditioning temperatures are allowed to fluctuate is a prime cause of tile joint gapping.
Excessive moisture in the substrate:Tile and adhesives are affected by substrate moisture. Tile installed over a concrete substrate with excessive moisture will grow slightly and later when the slab dries, the tile will return to its original size creating a uniform gapping. Adhesives over a damp substrate will remain soft and will allow the tile to slip.
Remember, Vinyl Composition Tile is a value engineered product that is used extensively because of its durability at an inexpensive price point. End users need to understand that modular products are not monolithic and unless all of the components listed above are met, you can expect to see gapping in some or all areas of the installation.