Slab Installation (Walls, Floors, Countertops)

What subfloor flatness is required for large-format tile or slab installation?

Large-format tile requires the substrate to be flat within 1/8" over 10 feet - tighter than the standard 3/16" requirement for smaller tile. Any variation beyond this causes lippage - where the edge of one tile sits higher than its neighbour. We use self-leveling compound or grinding to bring the substrate into spec before any large-format work begins.

What is lippage and how do you prevent it?

Lippage is when the edge of one tile is higher than the adjacent tile, creating a tripping hazard and an unprofessional look. We prevent it by using a tile leveling system with wedges and clips during installation. This keeps every tile in plane until the thin-set cures, ensuring a flat, consistent surface across the entire floor or wall.

Is weight a concern with large-format porcelain or stone slabs?

Yes - large format porcelain slabs and natural stone are heavy. Before specifying oversized material for upper floors, we assess the structural capacity of the floor system. Most residential wood-framed floors need evaluation for anything over 24"x24". We flag this during the design phase, not mid-installation.

What grout joint size is recommended for large-format tile?

Large-format tile is typically installed with very thin grout joints - 1/16" to 1/8" - to emphasize the slab-like appearance and minimize visible grout lines. This requires very precise substrate flatness and careful layout. The smaller the joint, the more critical the substrate prep becomes.