Porcelain vs ceramic vs natural stone
| Tile | What it is | Good to know |
|---|---|---|
| Porcelain | Dense tile with water absorption of 0.5% or less | Very durable (unglazed porcelain is harder than granite). Usually frost resistant, though not always. |
| Ceramic (non-porcelain) | Absorbs more water than porcelain | Fine for most indoor floors when the abrasion rating fits the room (below). |
| Natural stone | Marble, limestone, granite, travertine, slate | Needs sealing; resealing every couple of years. Acids like vinegar etch it; light marble and limestone stain. |
Sources: Tile Council of North America, Daltile. For outdoor tile in Minnesota, the tile has to be rated for exterior use and installed so water can't sit in the joints or setting bed (TCNA). That matters here: the Twin Cities average 55 to 60 freeze-thaw days each snow season (UMN Extension).
Three ratings to check on the box
- Abrasion class (0–5). How well a glazed tile resists wear. Class 3 is typical for most home interiors; 4 for most commercial. It's often called a “PEI rating,” which TCNA says is technically a misnomer (TCNA).
- Slip resistance (DCOF). ANSI A137.1 requires a DCOF of 0.42 or higher for tile recommended for level interior floors walked on when wet (Daltile). TCNA notes the number shouldn't be the only factor (TCNA). For bathrooms and entries, ask for it.
- Frost resistance, only if it's going outside or in an unheated space.
Big tiles need a flat floor
TCNA defines large-format tile as any tile with an edge longer than 15 inches. Big tiles look great, but they need a flatter floor: no more than 1/8" variation in 10 feet and 1/16" in 24 inches (Custom Building Products). The industry standard also calls for at least 80% mortar contact under each tile (95% in wet areas), and limits offset patterns on large tiles to 33% or less (Stone World / CTEF). That's why big-tile floors often need leveling first, and why long tiles are set at a 1/3 offset instead of a half-brick pattern.
What's under the tile matters most
- Stiff enough floor. Tile needs a floor that doesn't flex. The minimum is L/360 for ceramic and porcelain; natural stone needs L/720, twice as stiff (TCNA, CTEF).
- Uncoupling membranes. Products like Schluter DITRA go between the subfloor and tile to absorb movement and add waterproofing (Schluter).
- Movement joints. Tile needs room to expand and contract. In small rooms, a gap at the perimeter hidden by baseboard is enough; bigger areas need field joints too. Too few movement joints is the typical cause of tile “tenting” (popping up) (TCNA, TCNA).
Grout
| Grout | Use it for | Sealing |
|---|---|---|
| Unsanded cement | Joints under 1/8"; polished stone and glazed tile that sand would scratch | Follow the manufacturer |
| Sanded cement | Joints 1/8" and wider | Follow the manufacturer |
| Epoxy | Showers, kitchens, anywhere stains are a worry; highly stain and chemical resistant | Not needed |
| Single-component (e.g., Fusion Pro) | Stain resistance without epoxy's difficulty | Never needs sealing |
Sources: TCNA, Custom epoxy, Custom Fusion Pro. Tiles vary slightly in size, so grout joints need to be wide enough to hide it: TCNA says at least twice the average size difference between tiles (TCNA). Rectified tiles, cut to a precise size, allow the thinnest joints.
Heated tile floors
Electric floor heat goes under the tile: cables set into a membrane like Schluter DITRA-HEAT, or a pre-built mat like Nuheat (Schluter, Nuheat). Nuheat mats need a dedicated, GFCI-protected circuit and can't be cut or overlapped, and the installer has to record resistance tests before, during and after install or the warranty is void (Nuheat). It's easiest to add when the floor is already torn up.
What tile floors cost in the Twin Cities
Homewyse’s cost calculator for St. Paul (ZIP 55101, September 2026) puts a tile floor at $18.76–$23.13 per sq ft installed (Homewyse). Nationally, Fixr puts tile floors at $8–$14 per sq ft installed, and says 18" and 24" tiles cost more to install and decorative patterns add 10–20% (Fixr). Homewyse says $16.38–$20.21 per sq ft for basic 12×12 ceramic, including underlayment and disposal (Homewyse). Angi says $5–$15 for basic installs and $15–$30 high-end (Angi). Tile size, pattern, tear-out, leveling and membranes drive the difference.
If you're selling
We couldn't find national buyer data specific to tile floors, so we won't invent any. The practical side: fixing cracked tile and failed grout before listing heads off inspection items.
Where the money is best spent
- Prep over tile price. Most tile failures trace back to what's underneath: stiffness, flatness and movement joints.
- Porcelain for floors that work hard: entries, mudrooms and bathrooms.
- Heated floors while the floor is open. Adding them later means tearing the tile up.