Flooring Guides · 7 min read
Tile: Where It Belongs and What Goes Underneath
Tile almost never fails in the middle of a tile. It fails at the substrate and the joints, which is where the whole quote difference sits.
Published · 11 North Inc
Tile is the most durable floor you can put in a house and the one most often installed badly. The material itself is close to indestructible; what fails is everything underneath and between.
Porcelain, ceramic and stone
Ceramic and porcelain are both fired clay - the difference is density. Porcelain is pressed harder and fired hotter, so it absorbs far less water and resists wear better. For a floor, and especially an entry or a mudroom in this climate, porcelain is generally the right call. Ceramic is softer, easier to cut and less expensive, which suits a low-traffic bathroom. Natural stone is a different category: quarried rather than manufactured, genuinely unique, and porous. That porosity means sealing on installation and re-sealing periodically for as long as you own it. If nobody is going to keep up with that, porcelain that looks like stone is the honest recommendation.
The substrate decides everything
Tile is rigid and does not bend. When what it is bonded to moves, something gives - at the grout line or through the tile. That means the subfloor has to be stiff enough not to deflect underfoot, and flat enough that every tile sits in full contact with the adhesive beneath it. A tile bridging a dip is supported only at its edges and hollow in the middle, which is exactly how a tile cracks when a pan is dropped on it. Deflection is measured from joist span, spacing and subfloor thickness rather than judged by walking on it, because a floor can feel completely solid and still move more than tile tolerates.
Membranes and movement joints
Over a wood subfloor, an uncoupling membrane sits between substrate and tile and absorbs small movement without transmitting it. Chicago-area wood subfloors move measurably across a year, between humid summers and dry heated winters, so this layer earns its place. In a wet area, waterproofing is separate and non-negotiable - tile and grout are the wearing surface over the membrane that actually keeps water out. Large tiled areas also need movement joints where the floor meets a wall or another material. It is a detail that looks like nothing and it is why tiles tent or crack in a straight line across a big floor a year after installation.
Grout, and the joints that must not be grout
Cementitious grout needs sealing and absorbs what is spilled on it. Epoxy grout does not, costs more, and is harder to work with - in a kitchen or family bathroom it is usually worth the upgrade. Separately, wherever two planes meet - wall to floor, tile to tub, inside corners - the joint should be flexible sealant rather than grout, because those surfaces move independently and rigid grout cracks there every time. If your existing tile has cracked grout in exactly the corners, that is what happened, and re-grouting will produce the same result again.
Where tile earns its place in this climate
Entries and mudrooms, first. Chicago winters mean snowmelt, salt and grit arriving through the door for months, and nothing handles that like tile. Bathrooms and laundry rooms next, for the obvious reason. Kitchens are a genuine choice - tile is superb underfoot for durability and hard on the legs of whoever stands at the sink for an hour, so it is worth weighing against warmer options. Our tile flooring page covers what we install, and best flooring for Chicago-area homes sets tile against the alternatives room by room.