Introduction
Tile is only one item on the shopping list. A lasting installation is a system: the right tile bonded with the right mortar over the right substrate, with joints filled by the right grout and wet areas protected by a membrane. Get one component wrong and the whole system underperforms — the wrong mortar under porcelain, or sanded grout in hairline joints, can undo an otherwise perfect install.
This guide covers every material in that system — tile types, mortars, grouts, substrates, membranes, and sealers — and how to match them. Once you’ve chosen materials, the Tile Calculator turns your dimensions into quantities.
Tile Types
Ceramic
The workhorse: a clay body with a glazed surface. Affordable, easy to cut, and available in endless styles. Best for walls, backsplashes, and light-traffic floors. The glaze determines stain resistance — glossy glazes wipe clean; matte or crackle glazes need more care. Typical thickness 1/4–3/8 in (6–10 mm).
Porcelain
A denser, harder-fired ceramic with very low water absorption. Stronger than standard ceramic, suitable for floors, heavy traffic, and outdoor freeze-thaw areas (check the frost rating). Harder to cut — budget for a good wet saw and a diamond blade. Because it’s dense and often large-format, porcelain demands polymer-modified mortar, not basic thinset. Typical thickness 3/8 in (9–10 mm).
Natural Stone
Marble, travertine, slate, granite — each tile unique, each porous to some degree. Beautiful and unforgiving: stone needs sealing (before grouting, to prevent grout staining the stone), white mortar (gray mortar can shadow through light stone), and a deflection-free substrate — stone cracks where ceramic would survive. Grout joints are typically wider (1/8–1/4 in) to accommodate size variation between tiles.
| Tile type | Best uses | Key requirement |
|---|---|---|
| Ceramic | Walls, backsplashes, light floors | Standard thinset; easy cutting |
| Porcelain | Floors, showers, outdoors | Polymer-modified mortar; diamond blade |
| Natural stone | Feature floors, showers, walls | Sealer + white mortar + stiff substrate |
| Mosaic sheets | Shower pans, borders, accents | Conforms to slopes; grout-heavy |
| Subway / specialty | Backsplashes, shower walls | Layout planning; many cuts |
Mosaic Sheets
Small chips mounted on mesh in 12 × 12 in (30 × 30 cm) sheets — estimate them as 1 ft² (0.09 m²) per sheet. The mesh backing conforms to slopes, making mosaics the standard choice for shower pans. The trade-off is grout: a mosaic floor can use three to five times the grout of large-format tile over the same area, so budget grout accordingly (see the formula guide for the grout math).
Thinset Mortar
Thinset is the adhesive bed between tile and substrate. The bag you need depends on the tile:
- Unmodified (dry-set) thinset — basic cement-based mortar. Fine for small ceramic on walls and floors over stable substrates. Not for porcelain or large format.
- Polymer-modified thinset — with latex/polymer additives for stronger bond and flexibility. The default choice for porcelain, large-format tile (18 × 18 in / 45 × 45 cm and up), and any floor that sees temperature swings.
- Large-format tile (LFT) mortar — a thicker, non-slump modified mortar designed for 15-in-plus tiles; holds ridges without collapsing under heavy tile.
- Epoxy mortar — chemical-resistant, waterproof, stain-proof. Used in commercial kitchens and pools; overkill and unpleasant to work with for most residential jobs.
Coverage: a 50 lb (22.7 kg) bag covers roughly 60–100 ft² (5.6–9.3 m²) depending on trowel notch — 1/4 × 1/4 in for standard floor tile, 1/2 × 1/2 in for large format, V-notch for walls and mosaics. The cost guide prices mortar into the project budget.
Grout
Sanded vs. Unsanded
The joint width decides, not preference: unsanded grout for joints under 1/8 in (3 mm), sanded grout for 1/8 in and wider. Sand adds body that prevents shrinkage cracking in wide joints; in narrow joints the sand particles won’t fit and can scratch soft tile glazes. Standard floor joints of 1/8–1/4 in take sanded grout; tight 1/16-in wall joints take unsanded.
Cement vs. Epoxy Grout
Cement grout (sanded or unsanded) is the standard: affordable, easy to work, needs sealing in wet areas. Epoxy grout is stain-proof, waterproof, and chemical-resistant — and roughly three to five times the price, with a much shorter working time and harder cleanup. Worth it for a shower floor or kitchen backsplash behind a range; unnecessary for a bedroom-adjacent bath floor.
Grout Color
A practical note with cost implications: grout color affects maintenance more than looks over time. Dark grout hides staining in high-traffic areas; light grout shows everything. Contrasting grout emphasizes the tile pattern (and any lippage); matching grout minimizes it. Choose before you buy — grout color can’t be changed without re-grouting.
Substrates and Underlayment
Tile is only as good as what’s under it. The substrate must be flat, stable, and appropriately stiff:
- Cement backer board — the standard tile substrate for floors and walls. Screwed to the subfloor (floors) or studs (walls), seams taped with alkali-resistant mesh and thinset. Comes in 3 × 5 ft (15 ft²) sheets — estimate sheets as area ÷ 15, rounded up.
- Uncoupling membranes — sheet membranes that isolate tile from subfloor movement. Thinner than backer board, useful where height matters at transitions.
- Waterproofing membranes — painted-on or sheet membranes required in showers and wet areas per industry guidelines (TCNA). Tile and grout are water-resistant, not waterproof; the membrane is what keeps water out of the wall cavity. Non-negotiable in showers.
- Existing flooring — tile can sometimes go over sound existing tile or vinyl, but removal down to a proper substrate is the more reliable route. Never tile over carpet, cushioned vinyl, or deteriorating material.
Substrate deflection limits — L/360 for ceramic, L/720 for natural stone — are covered in the code compliance guide.
Sealers and Finishing Materials
- Stone sealer — penetrating sealer for natural stone tile and cement grout in wet areas. Reapply per manufacturer schedule (typically every 1–3 years in showers).
- Silicone caulk — 100% silicone, color-matched to grout, for every change of plane: corners, tub-to-tile, floor-to-wall. Grout cracks at planes; caulk flexes.
- Edge profiles — metal or PVC trim (Schluter-type profiles) for exposed tile edges at niches, half-walls, and transitions. Cleaner and more durable than a raw cut edge.
- Spacers and leveling clips — spacers set joint width; clip-and-wedge leveling systems prevent lippage on 18 × 18 in (45 × 45 cm) and larger tile. Budget $20–$30 per project for clips.
Matching the System: Quick Reference
| Project | Tile | Mortar | Grout | Extras |
|---|---|---|---|---|
| Bathroom floor | Porcelain 12 × 12 in | Polymer-modified, 1/4-in notch | Sanded, sealed | Backer board |
| Shower walls | Ceramic or porcelain | Polymer-modified, V-notch or 1/4-in | Sanded or epoxy, sealed | Waterproof membrane |
| Shower pan | Mosaic sheets | Polymer-modified | Epoxy or sanded, sealed | Waterproof membrane, sloped bed |
| Kitchen backsplash | Subway ceramic | Unmodified or modified, V-notch | Unsanded (1/16-in joints) | — |
| Large-format floor | Porcelain 24 × 24 in | LFT mortar, 1/2-in notch + back-butter | Sanded, sealed | Leveling clips, flat substrate |
Related Guides
- Tile Calculator Complete Guide — quantities for every material here.
- Cost Guide — what each material typically costs.
- Formula Explained — mortar and grout quantity math.
- Pro Tips — installation techniques for these materials.
- Code Compliance — substrate and waterproofing requirements.
Frequently Asked Questions
Can I use the same thinset for porcelain and ceramic?
Polymer-modified thinset works for both, so when in doubt, buy modified. Unmodified thinset is fine for small ceramic but inadequate for porcelain and large-format tile — the bond strength isn’t there for dense, heavy tiles.
Do I need to seal porcelain tile?
Glazed porcelain: no — the glaze is the sealer. Unglazed or polished porcelain: the tile body is dense enough to resist staining, but the grout joints still benefit from sealer. Natural stone is the material that truly needs sealing, before grouting.
How do I choose grout joint width?
Rectified (precisely cut) tile can go as tight as 1/16 in; non-rectified tile needs 3/16–1/4 in to absorb size variation. Larger tiles generally take wider joints. And remember the rule: under 1/8 in means unsanded grout, 1/8 in and up means sanded.
What’s the difference between backer board and drywall for tile?
Backer board is cement-based and dimensionally stable when wet; standard drywall deteriorates. In wet areas, tile goes over backer board plus a waterproofing membrane — never over plain drywall. (Moisture-resistant “green board” is not a substitute for a membrane in showers.)
Build the System, Not Just the Surface
Great tile jobs are systems where every component matches: tile to mortar, mortar to substrate, grout to joint width, membrane to wet area. Choose the materials as a set, check them against the table above, then run your dimensions through the Tile Calculator to turn the plan into a shopping list.
Disclaimer: Material recommendations here are general guidance for planning purposes. Always follow the specific instructions of your tile, mortar, grout, and membrane manufacturers, as product formulations vary. Calculator results are planning estimates — verify quantities with your supplier and consult a qualified professional for structural or waterproofing decisions.
