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HomeContentTimeless natural stone showcases luxury retail with a full system from CUSTOM

Timeless natural stone showcases luxury retail with a full system from CUSTOM

Westfield Valley Fair is the highest sales volume shopping center in California – the state with the most space dedicated to retail. Over the course of three years, $1.1B was spent to renovate this property in the heart of Silicon Valley, and expand the mall from 1.5M to 2.2M total square feet. Already a highly popular tourist attraction, the upscale center added 150 new stores with a focus on luxury brands. This extensive enhancement included installing 360,000 sq. ft. of natural stone, porcelain and glass tile with a full system from Custom Building Products. 

The objective for Valley Fair was “contemporary yet timeless,” which is the very essence of designing with natural stone. Over 240,000 sq. ft. of limestone, marble and sandstone were imported from Italian and Tunisian quarries in 90 full-sized shipping containers. Most of the stone was fabricated into honed 24” equilateral triangles and laid out in solid color, full-diamond and diamond bleed-out patterns that add tremendous sophistication to the site. 

Northern California Tile and Stone (NCTS), an NTCA Five-Star Contractor based in Sacramento, Calif., performed the work on both the renovation and expansion phases of the project. Performing demolition work, preparing the surface and setting pavers while the center remained open for business required tightly coordinated night work. To meet the aggressive schedule and minimize the impact on shoppers, a high-performance, rapid-setting system of tile installation products was chosen. 

Surface preparation

After removing existing tile, the slab was lightly shot-blasted to ICRI Concrete Surface Profile 3. This opened up the concrete to provide a clean surface for bonding an underlayment to bring the floor within tolerances for large-format stone tile. The low-prep CustomTech® flooring preparation products selected for the project do not always require this step, but given the age and condition of the slab, shot blasting was recommended to ensure the best bond to the substrate. TechPrime™ A Advanced Acrylic Primer was diluted 3:1 with three parts water and applied with a soft-bristle push broom to help drive the mixture into the substrate. This highly versatile primer and sealer can be used to prepare both porous and non-porous substrates for leveling. 

TechLevel 150 Self-Leveling Underlayment was pumped throughout the project to achieve a truly flat floor.
A smoothing tool is used to take TechLevel 150 Self-Leveling Underlayment to a feather edge at low spots in the slab.

After the primer dried, TechLevel™ 150 Premium Calcium Aluminate Based Self-Leveling Underlayment was poured to an average depth of 1/4”. High flow TechLevel 150 was pumped over the extensive concourses but also barrel mixed in the smaller areas as the prep work drew to a close. This super-fluid leveler can be batch mixed or inline mixed to scale for jobs of all sizes and the leveling work was self-performed by installers from NCTS. With a compressive strength greater than 4300 psi, TechLevel 150 is suitable for most projects and can be poured up to 1.5” per lift while resisting cracking. 

“We had great feedback from installers that had used other leveling products,” offered Erik Johnson, Project Superintendent with NCTS. “TechLevel 150 was a big factor in the successful outcome of the whole project. The tolerances were tighter, and we were not fighting substrate differences or seeing lippage.” 

To protect the natural stone on the mall’s busy concourses, RedGard® Waterproofing and Crack Prevention Membrane was specified throughout the project. RedGard controls in-plane crack transmission up to 1/8” in tile and stone floors and exceeds the requirements of ANSI A118.12 for crack isolation. This ready-to-use elastomeric membrane was primarily applied with an airless spray rig due to the immense size of the shopping center. A thickness of 40 wet mils of RedGard was achieved with two coats and subjected to quality control inspections with digital calipers. RedGard was also used in the new and renovated restrooms to provide waterproofing protection exceeding ANSI A118.10.  

Tile installation 

Both the renovated and new areas of the mall were set with 24” marble and limestone triangle pavers as well as 18” sandstone. All of the large-format stone on floors was set with Complete Contact-LFT Premium Rapid Setting Large Format Tile Mortar. This polymer-modified full contact mortar is especially designed for installing large and heavy materials on floors where it can eliminate back buttering with improved mortar transfer. Complete Contact is quite fluid to help wet out the back of the tile, yet holds ridges to support large pavers and the deeper notch trowels needed to install them. Crucial to fast-track renovations like Valley Fair, tile can be grouted in two hours and light foot traffic can be allowed in as little as four hours. High-performance Complete Contact-LFT also exceeds ANSI A118.15F for demanding, heavy duty applications like the mall. 

Complete Contact-LFT Mortar allowed installers to meet the minimum 95% coverage required for natural stone.
Directional troweling and SuperiorBilt Premium Notch trowels helped prevent voids beneath the tile.

The NCTS installers on the project employed back buttering and then lifted each tile to ensure the 95% minimum mortar coverage rate needed with natural stone. They used SuperiorBilt® Premium Notch trowels that are designed to promote ridge collapse and mortar transfer. Crew members were impressed by the strength of the SuperiorBilt margin trowel’s weld points, which held up over months of lifting the heavy, fully embedded stone.

“We had a quality end product and a minimal punch list because of good coverage with the right product, the right trowels and proper technique,” said Eric Witcher, General Manager of NCTS. “This was huge!”

Installing both glass mosaics and 12” x 24” porcelain tile on walls called for a versatile, high-performance, polymer-modified mortar. ProLite® Premium Large Format Tile Mortar was specified for both of these hard-to-bond-to materials in vertical assemblies that were installed in restrooms and accent areas off the main concourses. ProLite offers high bond strength in a lightweight formula with excellent handling characteristics. 40% lighter than traditional mortars, ProLite will not sag on walls or slump on floors, and exceeds ANSI A118.15TE for thixotropic performance and extended open time for adjustment.  

“We love ProLite!,” said Witcher. “It is so versatile – just a great product.” 


Nearly all the tile on the project was grouted with Prism® Ultimate Performance Cement Grout.  Prism’s calcium aluminate-based formula delivers consistent color without mottling or shading and it will not contribute to efflorescence. Recycled content and fine aggregate sand provide a smooth consistency that is easy to clean as well as 30% lighter than other grouts. With high early strength and dense, stain-resistant joints, Prism was the perfect choice for Valley Fair’s rapid-setting requirements.  

Prism Ultimate Performance Grout was installed on walls as well as high-traffic floors in all concourses.

“I have used a lot of grout in my lifetime and Prism is awesome stuff!” offered Johnson. “We had great production rates because it is so easy to use and the rich color was completely consistent throughout.”  

“We had no issues due to traffic,” added Witcher. “Any other product would have been damaged; I was shocked to see how well it held up.” 

Soft movement joints at perimeters and intervals in the field were placed and filled with permanently flexible sealant per TCNA Detail EJ171.

Prior to grouting, the honed – and therefore more porous – natural stone pavers were sealed with Aqua Mix® Sealer’s Choice® Gold. Sealer’s Choice is a premium, natural look, water-based penetrating sealer that provides maximum stain protection while allowing moisture vapor transmission. After curing, the Prism cement grout was also sealed. For added chemical resistance due to cleaning regimens, restroom floors were grouted with CEG™-Lite 100% Solids Commercial Epoxy Grout. 

TCNA guidelines were carefully adhered to throughout the project, including Detail EJ171. In accordance with EJ171, movement joints were placed every 20 feet on ground and every 12 feet on suspended slabs. Soft joints were included at all perimeters and changes of plane, with additional accommodation made for tile exposed to sunlight. Joints were filled with Commercial 100% Silicone Sealant, which remains permanently flexible to protect tile and grout in the assembly from expected movement. “The silicone was an excellent color match to the grout,” said Johnson. “It is hard to see the movement joints – just as it should be.”

24” equilateral triangles of marble and limestone were set in full diamond and diamond bleed patterns.

With a full system of surface preparation, tile-setting, grout and care products from CUSTOM, Westfield Valley Fair qualified for a 20-year installation warranty. 

“Custom’s technical rep invested a lot of time with our general contractor and our architect, and they utilized all of their assets and resources to help wherever needed,” said Witcher. 

“I’ve worked with Custom for 30 years,” added Johnson. “They show support and advocacy from beginning to end on every project.”

Six different natural stones featuring Italian marble were used to create the signature atrium mosaics.
Westfield Valley Fair is the perfect luxury showcase for designing with natural stone.
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