Quality Control of Venetian Glass Mosaic Tile Installation in Large Swimming Pool and Plaza PoolBackground: A high-end large estate was under construction in a desert community. It was new construction of a 32,000 square foot house, and the owner wanted a series of swimming pools to be interconnected. He wanted to have a large pool plaza area with islands covered in stone. A dark blue Italian Venetian glass mosaic was selected to cover the concrete substrates of the pool and plaza areas. It took almost two years to complete this expansive project, so the tile had to be installed during the summer months when the temperatures were over 110 degrees Fahrenheit.
Request: CTaSC was retained to write the installation guidelines for the mosaic tiles as well as for the mechanical anchored exterior stone veneer and for over 40,000 square feet of stone flooring. CTaSC was to specify the tile installation products for glass mosaic tiles to be installed in all of the various pools, spas, and water features. CTaSC was to provide full time quality control services that included various quality assurance testing.
Glass Tile Mosaic Installation Guidelines and Products: CTaSC specified a single source installation system from the manufacturer of the installation products that came with a 10 Year Labor and Material Warranty.
It was specified to float the concrete shotcrete walls with a latex modified mortar to establish the shape of the pool that included building the infinity edge that had to be perfectly level to allow for an even flow of water to cascade over the side of the pool.
A liquid applied waterproof membrane was specified to go over the floated mortar walls of the pool.
A flexible epoxy flashing mortar was specified to flash and treat all penetrations in the pool including the light canisters.
An ASTM C920 sealant was specified to fill all transition joints and movement joints in the pools.
A traditional glass tile mosaic installation method was specified for installing the paper face mounted glass mosaic tiles. A special high-strength acrylic latex additive was mixed with a blue non-sanded grout that was to be used as both the adhesive and the grout. The mosaics were installed in a way so it was being adhered and grouted all in one step. This allows the tile to be fully encapsulated in the mortar. After the paper is removed from the tile any pinholes in the grout are filled with the same mortar.
A Quality Assurance and a Quality Control Plan was incorporated in the mosaic tile specification.
Quality Assurance Testing - The concrete shotcrete pool shells were sounded to determine if there were any voids in the concrete. When a hollow area was found it was hit with a hammer to see if it collapsed into a void. There were many voids found that had to be repaired.
Quality Control Services and Inspections: CTaSC developed and implemented a quality control (QC) plan to ensure that substrates were properly prepared, that the installation products were properly stored and used, and that the tile was properly installed and protected from extreme climatic conditions.
CTaSC QC inspectors are seasoned journeyman or master tile installers with years of experience. They are ITS Verified tile installers through the University of Ceramic Tile and Stone (UofCTS) that verifies they understand the current industry standards. Team Leader Donato Pompo manages the inspectors by debriefing them and consulting with them each day.
CTaSC inspectors prepare daily inspection logs and correction lists to go with their daily inspection photos and videos.
Since the installation products being used on the project had limitations of not being stored or used in temperatures over 90 degrees Fahrenheit, a tent was built over each of the three pools. Air exchangers and a water mist system were installed in the tents, which brought the temperature down to about 80 degrees Fahrenheit.
During the glass tile mosaic installation the CTaSC inspectors required the tile installers to remove recently installed sheets of tile to verify they were achieving substantially 100% adhesive mortar coverage. The CTaSC inspectors had to instruct many of the installers on how to properly install the tiles.
After the glass tile mosaics were installed and cured for a week the CTaSC inspectors would sound the glass tiles to see if there were any hollow sounds that would indicate the tiles were not fully bonded. Any hollow sounding areas were required to be removed and replaced.
Upon completion the pools were filled with water at the recommend rate of 2 inches per hour to avoid any differential pressures to the tiles.
Donato Pompo, CTC CMR CSI CDT MBA, is the leading tile and stone forensic expert and consultant in North America, and he is a National Tile Contractors Association Recognized Consultant. Donato is the founder of CTaSC.