A brief historyA brief history: This is an installation in a school, approximately 3,500 square feet of vinyl composition tile (VCT) was installed over a 1/4-inch plywood underlayment. There are three classrooms, two of the classrooms have a one-inch plywood sub-floor, and one classroom has 2-1/4-inch strip hardwood flooring installed over a one-inch plywood sub-floor (Photo 1). After the underlayment was installed, the architect conducted a site inspection and noticed a ridge in the middle of each classroom along the entire length, after inspecting the ridge in the underlayment; the architect requested that corrections be made to the classrooms, prior to the installation of VCT, as the ridge would be in traffic areas. There was a meeting arranged with the architect, general contractor, structural engineer, flooring manufacturer's representative, and flooring contractor, where it was determined that the floor would be lowered from underneath in two of the classrooms. The high point happened to be over columns in the basement; approximately one inch was cut off the top of the columns to minimize the high spot. Two of the three rooms were dropped and level to within 3/8-inch across the 22-foot wide width of the rooms; it was determined that lowering the sub-floor in the third room would be a problem with the strip flooring, so no corrective measures were taken in that classroom. After the lowering of the sub-floor, the VCT was installed. Approximately two weeks after the installation the flooring contractor received a phone call from the general contractor stating that the floor was displaying movement and bubbles in random areas of the entire installation. The flooring contractor sent his installers out to make corrections, the installers removed tiles in areas that were displaying movement, fastened the underlayment with screws and replaced with new tile. Over the next week the flooring continued to display more and more bubbles six inches in diameter to one foot in diameter with movement up to 1/4-inch, to the point where another site meeting was held. The flooring contractor insisted that, due to the sub-floor being lowered after the underlayment was installed, the installation contractor was not responsible. The general contractor, knowing that the floor would not be accepted, removed the VCT tile and requested an inspection to determine who was at fault.
The underlying issuesPhoto 2 shows a level in the middle of the room that was not lowered; there was a high spot in each classroom running the length of each room; each room is approximately 22 feet wide. Photo 3 is the room that was not dropped; the photo shows at two feet there is a 1/2-inch variance of the sub-floor and underlayment from level. Photo 4 is showing the variance in eleven feet with a laser placed at the middle of the room to the wall; the laser was set level one inch above the floor; therefore, there is a variance of one inch in eleven feet.
The entire installation of VCT and underlayment was removed and new underlayment and VCT re-installed. There was also a time factor as the school was opening for classes within two weeks from the time that the flooring was being removed, putting more pressure on the flooring contractor, who was the low bid, to finish this project and possibly delaying other installations. Unfortunately, due to the lack of education or ignorance, the flooring contractor ended up paying for double the amount of VCT, underlayment, and labor, along with having to pay for the take up and removal of the first installation of VCT and underlayment by the general contractor.
The lesson to all of this, follow the manufacturers' recommended installation guidelines and educate and train youself and your installers to avoid these types of pitfalls that could ultimately put you out of business.