CUSTOM system manages movement in sunny atrium
The AT&T Tower in Nashville, Tenn. has several identities, – including its street address – but the site is usually known as the Batman Building. This skyscraper’s silhouette, with its distinctive spires resembling the comic book superhero’s ears, is an iconic part of the skyline in a city well-known for distinctive structures. When the famous tower’s atrium lobby was renovated by Turner Construction, a complete system from Custom Building Products was specified for the award-winning tile installation.
The design concept was to create a warm Southern welcome using tile. Coincidentally, one of the main challenges on the job was handling thermal cycling from atrium skylights and floor-to-ceiling windows. The architects at Atlanta-based TVS Design needed a system that allows the assembly to expand and contract with daily exposure to sunlight. CUSTOM is the Basis of Design at the firm, and they were able to specify an installation system with the appropriate amount of flexibility. This included a full-coverage crack-isolation membrane and a tight grid of movement joints to relieve the stresses of thermal cycling.
Throughout all phases of the project, product application and installation was executed by BECA Commercial Flooring.
Surface preparation
The lobby previously housed a multi-level water feature, so the concrete required significant demolition and remediation. Then, the entire substrate was treated with TechPrime™ A Advanced Acrylic Primer prior to leveling. This product is ideal for concrete slabs but is also appropriate for non-porous surfaces, making it a true all-purpose primer.
CUSTOM supplied a large pump truck with a 3” hose to mix and place the flowable cement underlayment. The company also sent a team of field reps to the site to assist with the logistics of pumping the leveler. TechLevel™ 125 Deep Pour Self-Leveling Underlayment was placed at an average depth of 2″ aided by leveling pins. TechLevel 125 is a high-flow, crack-resistant leveler that achieves up to 4,000 psi compressive strength and can be placed up to 3″ deep in a single pour.
The entire leveling process of the 12,000 sq. ft. lobby took less than five hours and the surface was ready for tile installation in four hours. Choosing a high-performance calcium aluminate formula saved the crew many days versus using a gypsum-based leveling product.
“This project was very successful,” said Walt Gordon, BECA’s co-owner. “From the support we got from Custom’s technical reps on-site to the performance of the products, we could not have asked for more.” These reps included Todd Tucker, Territory Manager; Matthew Minney, Business Development Manager, Surface Preparation and Chip O’Rear, CSI, CCPR, CTC, CCSMTT, LEED AP, Commercial Architectural Services Representative.
“Everyone was extremely helpful; just amazing,” added Daniel Long, project manager with BECA.
To protect the tile from movement stresses, Crack Buster Pro® Crack Prevention Mat Underlayment was specified per TCNA Detail F125 with full coverage. This self-bonding, fabric-reinforced, asphaltic membrane isolates tile and natural stone from cracks in the substrate. The ability to absorb thermal expansion and contraction stresses and relocate saw-cut control joints made this membrane a critically-important component of the tile assembly. Crack Buster Pro is a high-performance crack-isolation membrane that meets the requirements of ANSI A118.12 and protects tile from in-plane movement up to 3/8″.
“We pushed for Crack Buster Pro on the job because we love this product,” offered Long.
Tile setting
This project is a jewel box of stunning tile, with subtle use of textures and a neutral palette that bring a sense of serenity and luxury to the building. Full-sized gauged porcelain tile panels (GPTP) provides the visual solidity of stone to anchor the tower, while setting courses up the walls evokes a very contemporary look.
Tonya Knapp, project manager and senior job captain with TVS Design said, “Gauged porcelain tile embodied the concept and allowed reaching up to the six-story glass roof, elongating the height.”
A spider crane was employed by the tile installers to move and place the fragile panels on walls and a lippage control system was used at the edges per the installation standard, ANSI A108.19.
Crews used a spider crane to assist in lifting and transporting in the very large gauged porcelain tile panels. Lightweight ProLite is creamy and easy to trowel plus it contributes to LEED certification. ProLite supports the weight of heavy tile without slumping while the mat underlayment provide crack isolation.
The size (over 5’x10′) and vertical height of the tile formats at the Batman Tower called for a bonding mortar with substantial superpowers. ProLite® Premium Large Format Tile Mortar is just such a hero, strong and versatile enough for nearly any tile installation. This lightweight mortar is designed to support large-and-heavy tile without slumping on floors or sagging on walls, and exceeds ANSI A118.15HTE. Installers used flat back-troweling and vibratory tools to assist with maximum wet mortar transfer and to help prevent voids under the tile.
With its superior shear strength and thixotropic properties, ProLite is a popular choice for renovation projects involving reskinning vertical surfaces. ProLite is 40% lighter than traditional mortars, making it easier to carry around jobsites, plus extra smooth and creamy to trowel. Formulated with recycled content, ProLite contributes to LEED® certification and is also GreenGuard® Gold certified.
“Wherever there are weight limitations, or when we need premium performance, we try to use ProLite,” said Long.
Grouting and sealant
This site’s atrium allows maximum light to showcase the tile design but creates other challenges. TVS Design included soft movement joints using the spacing requirements found in the TCNA Handbook’s Detail EJ171. These joints were filled with Custom’s Commercial 100% Silicone Sealant, which conforms to ASTM C-920 and remains permanently flexible.
Many of the grout joints – including those surrounding each of the full-size gauged porcelain tile panels – received color-matching silicone instead of traditional grout. This is a recommended treatment as GPTP dimensions often coincide with the movement joint placement. Silicone’s flexibility provides better protection for the porcelain panels.
Additional grout joints were filled with Polyblend® Plus Sanded Grout, now enhanced to improve performance, finished color and color consistency. Polyblend Plus is a polymer-modified, cement-based sanded grout that meets ANSI A118.7 and produces hard, dense joints that resist shrinking, cracking, and wear.
Several different GPTP products from Ceramic Technics and Trinity Tile were used, with panels measuring up to 64″ by 128″. The primary smaller porcelain tile included materials from these distributors, plus Traditions in Tile; these formats measured up to 48″ and 60″ in length.
Thanks to a durable, protective CUSTOM system that was specified and installed on the project, the Batman Tower will continue to impress visitors and serve ownership for many years.
