Whether you are an installer or a distributor of tiling materials, I’m sure you’ve noticed the growing trend toward larger tiles. This is easy to understand. More customers and designers are drawn to the beauty and practicality that large-format tile (now known as large and heavy tile (LHT)) brings.  

Tiles become “large-format” when they have at least one side greater than 15 inches while heavy tiles weigh more than five pounds per square foot. Common sizes of LHT include 18” x 18”, 12” x 24” and the popular 6” x 24” plank. And from an aesthetic standpoint, the larger tiles give the space they are installed in a “roomier” feel. The tile surfaces have fewer visual interruptions from grout joints, giving the perception of an extended environment.

In terms of convenience, LHTs have everything one could want in a tile surface. For starters, they are highly durable, especially when you start getting into gauged porcelain tiles. Also, the reduction in grout joints leave fewer crevices that need cleaning. LHTs come in a wide array of colors and designs, and their cost per square foot is quite comparable with regular-sized tiles. What’s more, their large size makes them easy to cut into practically any needed shape.  

LHTs are exceptional surface materials; however, their installation demands are equally unique. Special attention must be paid to the techniques, tools and materials employed for LHT installations. As an industry, the standards and guidance for installing these bulkier tiles has changed with an eye toward providing finished surfaces with longevity and elegance.

The Tile is Large, So Take Charge

LHTs enjoy the same durability as other tile surfaces, but as tile size increases so does the importance of checking every box in the installation process. This diligence starts at the substrate. Proper surface preparation is a must for any flooring installation, but for LHTs it is simply indispensable. Negative effects resulting from substrate irregularities are magnified with larger tiles. The steps to remedy a poor substrate are largely the same for tile projects; however, defect tolerances change LHT installations.  Tiles with any side greater than 15” have a maximum allowable substrate variation of 1/8” in 10 feet from required plane. Furthermore, variation cannot exceed 1/16” in 24” when measured from high points in the surface.

The size and heft of LHTs also comes into play. Tiles with long sides will have more pronounced lippage issues if they are set in mortar that slumps. Tiles with more weight can also slip down a wall surface without a proper bond to hold them in place. These problems can partially be remedied through lippage control systems, spacers and ledger boards, but using a mortar designed specifically for larger, heavier tiles is essential.

The Right Materials Play a Large Part

High-performance surface preparation materials will help ensure you achieve the flatness necessary for a long-lasting installation. Uneven walls and vertical surfaces need a patching or rendering compound.  Fast-setting, polymer-modified compounds like Merkrete’s Pro Patch AL1 quickly even out wall surfaces, establishing a true substrate for a flush installation. Floors exceeding acceptable tolerance are easily smoothed out with an installer-friendly flowable hydraulic cement underlayment. Premium-grade products like Merkrete’s SLU Underlayment are pourable, pumpable, free-flowing Portland-cement-based materials that can be applied from feather edge to ¾” in a single pour for a completely flat surface.

With a sound substrate to work on, LHTs demand mortars engineered to deliver the best bond for big tile. Single-component, polymer-modified mortars like Merkrete’s 855 DUSTLESS XXL LHT possess non-sag, non-slump properties that bond instantly with tile to securely lock it to the substrate. Those installing larger, heavier tiles may benefit from a lightweight, high-yield mortar like Merkrete’s 820 DUSTLESS Merlite. It’s 30-lb. bag achieves the same coverage as a typical 50-lb. bag, without adding extra load to the mortar/tile combination. Floor installations call for materials like Merkrete’s 720 DUSTLESS LHT mortar. These contain flowable technology that aids in attaining proper mortar coverage while supporting tiles with non-slump properties. Each are highly workable, easy to spread and produce significantly less dust around the jobsite.

No Project Too Large

Large-format tiles are quickly becoming the norm in new constructions and renovations. Word has spread about the eye-pleasing, maintenance-free installations, and many of you have seen a sizeable portion of your business devoted to LHT projects. The demand for these installations (and the correlating demand for your skilled services) makes them well worth the upfront planning, extra precautions and careful material selection they need.