Tile and grout: porcelain, ceramic and stone, slip resistance and sealing
Tell porcelain from ceramic by how much water it absorbs, read wear class and DCOF for the room, know which grout you have, keep flexible sealant at the corners, and clean without dissolving the grout.
- Start here: the essentials
- Porcelain, ceramic or stone: what the tile is
- Slip resistance: what DCOF tells you
- Stone tile: etching, staining and sealing
- Grout: types, sealing and cleaning
- Corners, cracks, white residue and showers
- Where the sources differ
- See it: the Brennans' bathroom and Harold's
- Practice: identify, record, check the corners
- Your home
- Check your work
- Knowledge check and scenario
Start here Essentials
For a first pass, this chapter asks you to find out what your tile and grout are, deal with a wet floor where someone at risk of falling bathes, and keep acids off cement grout. Nothing here asks you to set, cut or remove tile.
- Find out whether the tile is porcelain, ceramic or stone. Use the box, the spec sheet, the PTCA mark or the supplier (what the tile is).
- For a floor walked on wet, read the DCOF, and add a non-slip mat or strips where someone at risk bathes. No DCOF on an old floor is common; the mat and strips do not wait for it (slip resistance).
- Identify the grout type and check the corners for flexible sealant. The installer's invoice or the grout bag says which grout; the corners should have sealant, not grout (grout, corners).
- Clean with an alkaline or neutral cleaner, never vinegar, on cement grout. Acids dissolve cement grout and etch some stone (cleaning grout).
Minimum time: about 30 minutes for one bathroom or kitchen. Done when: the installed register names the tile type and grout, and the care schedule has a grout and sealant check.
Porcelain, ceramic or stone: what the tile is Understand
Three kinds of tile end up in most kitchens and bathrooms: porcelain, other ceramic tile, and natural stone. They are cleaned, sealed and rated differently, so the first job is to know which one you have. The Tile Council of North America (TCNA), the tile industry's trade association and secretariat for several US tile standards, is the main source for this chapter.
Porcelain is a number
Ceramic tile is the broad family of fired clay tile, and porcelain is one kind of it. Porcelain tile is ceramic tile that absorbs very little water: TCNA defines it as tile with water absorption of 0.5 percent or less, measured by the test ASTM C373. Tile that absorbs more than 0.5 percent is non-porcelain, which is what most people mean by "ceramic" (TCNA, Porcelain vs. Non-Porcelain). Convention
The word on a box is not the test. TCNA says there have been many instances of non-porcelain tile advertised as porcelain. Its answer is the Porcelain Tile Certification Agency (PTCA), which certifies that a tile meets the 0.5 percent limit; certified tile can carry the PTCA mark on its packaging and marketing (TCNA, Porcelain Tile Certification). If a tile is sold as porcelain without the mark, look on the spec sheet for a water absorption figure and the test it was measured by. A figure of 0.5 percent or less by ASTM C373 is the definition; "porcelain look" or "porcelain body" with no number is a description. Check the spec sheet
What porcelain changes for you, by TCNA's account:
- Glazed or unglazed. A glaze is a glassy coating fired onto the face of the tile. TCNA says glazed porcelain is usually easier to clean, and unglazed porcelain may have better slip resistance.
- Through-body. In through-body (unglazed) porcelain, the color runs all the way through, so a chip shows the same color. TCNA calls it harder than granite.
- Frost. TCNA says low absorption usually means a tile resists frost, but not in every case. For outdoor use, read the maker's stated area of use. Porcelain is not the only tile rated for outdoors.
- Installation. Porcelain is harder to bond and cut. TCNA says this matters to the installer, and little to you if the right materials are used.
Ceramic tile basics that apply to every kind
TCNA's ceramic tile FAQ makes three points that hold for porcelain and non-porcelain alike (TCNA, Ceramic Tile FAQ):
- Grout is the filler in the joints between tiles. TCNA says it is joint filler and is not designed to hold the tile in place; the setting material underneath does that.
- Grout joints are not waterproof. In a shower, the waterproofing is in the layers under the tile, not in the grout (see showers).
- Where tile meets a wall, a tub, another plane or another material, TCNA calls for a movement joint (also called a control or expansion joint), filled with a flexible sealant rather than grout.
Wear class on glazed tile
A glazed tile's face can wear: the glaze dulls or its pattern fades where people walk. The test behind most wear ratings is ASTM C1027, which measures a glazed tile's resistance to visible surface abrasion. A lab rotates an abrasive load on the tile and compares the worn and unworn areas by eye; a staining agent can be used to show where dirt gets trapped (ASTM C1027, scope). Retailers show the result as a numbered "PEI" class. Convention
The test's own scope sets limits on what the result means. It may not evaluate irregular surfaces properly. It makes no provision for the difference between light and dark tiles, although wear shows differently on each. It does not evaluate loss of gloss well. It applies to glazed tile, so unglazed through-body porcelain is not rated this way. We found no standards-body or maker page that sets out what each class number means, only retailer pages, so this manual does not print a class table. Read the tile maker's own stated area of use (floors, walls, residential, commercial) and treat the class as one input. Product-specific
Life figures and quantity
NAHB's 2007 survey gives 75 to 100 years for tile floors, and InterNACHI's chart gives the same range (NAHB, PDF; InterNACHI). Both call their figures guidelines. Neither gives one for grout, and no source we found does. Choose your own figure for the cost per year calculator and write where it came from (How to compare finishes explains why).
The quantity calculator takes the room's area, adds an overage for cuts and breakage, and rounds up to whole boxes. Use the overage in the tile maker's or installer's instructions. Where neither gives one, the calculator's 10 percent is this manual's default, not a tile industry figure. This manual's rule We found no TCNA or tile maker page on buying from one production lot or keeping spare tile, so the calculator's spare box is also our convention: a broken tile years later is easiest to replace from the same batch. Write the lot or shade number on the installed register.
Slip resistance: what DCOF tells you
A wet tile floor is slippery, and the number on the spec sheet that speaks to it is the DCOF. The dynamic coefficient of friction (DCOF) measures how much a surface resists something already sliding across it; a higher number means more resistance. The US test is ANSI A326.3, which TCNA publishes free (ANSI A326.3, PDF). Physical principle
What 0.42 means
The standard sorts floors by where they will be used, and sets a figure for some of them:
| Use category | Where | What the standard asks |
|---|---|---|
| Interior, wet | Level interior floors walked on when wet; the standard names home interiors, bathrooms and kitchens included, if level, clean, maintained and free of standing water | Wet DCOF of 0.42 or more, or as the maker declares |
| Interior, dry | Level interior floors kept dry | Dry DCOF of 0.42 or more |
| Interior, wet plus | Public showers, pool decks, locker rooms, steam rooms | As the maker declares; a note in the standard says generally at least 0.50 wet |
| Exterior; oils and greases | Outdoor floors; floors that get oil or grease | As the maker declares |
For a home bathroom or kitchen floor, the line to look for on the spec sheet is a wet DCOF of 0.42 or more, or the maker's use category "interior, wet". Daltile, one large maker, puts it the same way: tile recommended for a level interior space walked on when wet should have a DCOF of 0.42 or more (Daltile, DCOF). Convention The standard sets no figure for shower floors, ramps or slopes, so for a shower floor ask the maker what it declares for that use.
What it does not tell you
The standard is plain about its own limits. It says DCOF can provide a useful comparison of surfaces but does not predict the likelihood that a person will or will not slip, and that the measured value should not be the only factor in choosing a floor. It lists what else matters: shoe soles and their wear, what is on the floor, how a person walks, their condition, slope, maintenance, the surface and drainage. It also says:
- An installed floor's DCOF can change over time with wear and contaminants. The figure on the spec sheet is for new tile in a lab.
- Surfaces with a higher DCOF may be harder to keep clean, and a dirty floor can itself be a hazard.
- The 0.42 figure belongs to one measuring device (the BOT 3000E). Another device's numbers are not directly comparable.
In a bathroom the contaminant is often soap. The standard lists contaminants among the factors its number does not capture, which is one reason a mat or strips still matter on a floor with a good figure.
A DCOF figure is one lab measurement on new tile. It does not make a floor safe: wet or soapy floors, footwear, wear and cleaning change how it behaves, and the standard itself says the number does not predict whether a person will slip. There is no home version of the test, so an old floor with no figure stays unknown. Whether a bathroom suits a particular person who has fallen or is unsteady is for that person and their clinician; this manual gives no medical advice, and it does not teach tile setting. Ask the person and their clinician
Mats and strips
For a tub or shower floor that is slippery, the CDC's home fall checklist says to put a non-slip rubber mat or self-stick strips on it, and it lists grab bars inside and beside the tub and next to the toilet (CDC, Check for Safety, PDF). The CPSC's checklist for older consumers says slip-resistant surfaces are especially important in places that get wet, such as bathrooms, kitchens and entries, and accepts rugs and mats that are slip-resistant (CPSC, Home Safety Checklist, PDF). Convention Fitting grab bars is an installer's job. A bath mat on the floor outside the tub is a rug like any other, so Carpet and rugs applies: it should not slide or curl.
These steps do not wait for a DCOF. On an old floor nobody has a figure for, they are the whole answer this manual gives.
Stone tile: etching, staining and sealing
Natural stone tile (marble, slate, granite and others) is cut from rock, so its behavior depends on its minerals. The Natural Stone Institute (NSI), the stone industry's trade association, sorts stone into two groups (NSI, Care and Cleaning of Natural Stone): Physical principle
- Calcareous stone is mainly calcium carbonate (the mineral calcite). NSI says it is sensitive to acidic solutions. Marble is the most familiar example.
- Siliceous stone is mainly quartz, feldspar and mica. NSI says it is generally resistant to most acids found in kitchens, but still does not recommend acidic cleaners on it, because it can contain small amounts of acid-sensitive minerals.
NSI's page has a chart naming which stones fall in each group, but it is an image we could not read. Ask the supplier which group your stone belongs to, and write the answer on the installed register.
Etching and staining are different
An etch is a dull spot where an acid has eaten into the surface of calcareous stone. It looks like a dull mark or water ring, not a color. A stain is something that has soaked into the stone and changed its color. NSI's marble article says lemon, tomato, juice, alcohol and vinegar etch marble, and a restorer quoted there says sealer does nothing to protect against etching (Use Natural Stone, marble care). NSI's care page says products containing lemon, vinegar or other acids may dull or etch calcareous stone. Etch marks are repaired by refinishing or repolishing, which is a stone restorer's job, not a cleaning job.
Sealing slows stains; it does nothing for etching
A stone sealer is a liquid that soaks into the stone and makes it repel water and oil. NSI calls most of them impregnators that act as a repellent. Its page says sealing makes stone more stain resistant, not stain proof, and that many stones do not need sealing. It gives no interval and says to ask the supplier or sealer maker. Product-specific
The test for whether a stone is absorbing is a drop of water. Laticrete, a sealer maker, describes it: on a clean, dry surface, put a drop about 1 in. across and wait 5 to 30 minutes; if it darkens the stone, the stone is absorbing; if it beads, the stone is sealed or very dense (Laticrete, test whether stone is sealed). Test it The care schedule's line is to reseal only when the water test says so and the maker allows it. How often that comes up is a source disagreement, under Go deeper.
Cleaning stone tile
NSI's routine: a neutral cleaner, stone soap or mild dish detergent with warm water; rinse and dry; change the rinse water often. Dust mop floors often, because grit scratches. Scouring powders and creams may scratch. NSI also warns that some rust removers, including some laundry rust removers and toilet bowl cleaners, contain hydrofluoric acid, which attacks all stone, granite and quartzite included. Read the label of anything used near a stone floor. TCNA adds that sanded grout should not be used with marble or other easily scratched tile; marble is usually set with narrow 1/16 in. joints and unsanded grout (TCNA, Grout FAQ).
Stone counters work the same way and have their own tests and questions in Countertops. Cutting, grinding or drilling any stone or tile makes dust that can contain crystalline silica; that work belongs to a pro with dust controls (Countertops covers what to ask).
Grout: types, sealing and cleaning
Grout is where most tile care goes: TCNA says cement grout is porous and absorbs stains, while a glazed tile's face does not need sealing. The type of grout decides whether it is sealed and what cleans it, so find out which one you have: the installer's invoice, the grout bag or bucket, or the installer. If nobody knows, record "unknown" and care for it as cement grout, the cautious reading, since acids dissolve cement grout. This manual's rule
The grout families
| Grout | What it is | Sealing | Notes |
|---|---|---|---|
| Cement grout, unsanded | Cement-based; for joints narrower than 1/8 in. | TCNA calls sealing it a very good idea | Porous; absorbs stains; dissolved by acids |
| Cement grout, sanded | Cement with sand; for joints 1/8 in. and wider (more heavily sanded above 3/8 in.) | As above | Not with marble or easily scratched tile |
| Polymer-fortified cement grout | Cement grout with added polymer (standard ANSI A118.7) | Per the maker | Still cement, so still acid-sensitive |
| Epoxy emulsion grout | Cement plus epoxy (ANSI A118.8) | Per the maker | TCNA says it is not stain proof |
| 100% solids epoxy grout | All epoxy, with no cement (ANSI A118.3) | TCNA says it is virtually as stain proof as the tile | Harder to install, can look plastic, cures for days longer, and costs three to eight times as much as cement grout |
| Single-component (premixed) | Ready-to-use grouts, some urethane-based, sold in a bucket | Several are sold as needing no sealing | Limits differ by product; read its data sheet |
Sources: TCNA's grout, epoxy and cleaning FAQs (Grout; Epoxy Mortar; Cleaning Grout). TCNA adds that no standard sets joint width; rectified tiles (cut to precise size) allow narrower joints than rustic ones, and grout should not be put on a tile's beveled edge.
Single-component grouts deserve a closer look before you rely on "no sealing". One maker's premixed grout is sold for showers and outdoors; another's data sheet rules out exterior use, steam cleaning, acid-based and no-rinse cleaners, and steam rooms, and says to protect it from mustard, salad dressing and vinegar. Each is accurate for its own product. The side by side is under Go deeper. Product-specific
Sealing cement grout
TCNA says sealing cement grout is a very good idea, and that sealing glazed tile is not, because the glaze outlasts any coating. It describes two kinds of sealer:
- A penetrating sealer soaks into the grout and repels water and oil from inside. TCNA says these cost more, last longer and let vapor pass.
- A topical sealer forms a film on the surface. TCNA says these cost less, can look like plastic and wear off under traffic. Its white-residue FAQ adds that topical acrylic sealers can turn white with moisture.
Some penetrating sealers are now sold as free of PFAS, the long-lasting "forever chemicals"; Aqua Mix, for one, sells a PFAS-free version and states it protects for up to 10 years under normal wear (Aqua Mix Sealer's Choice Gold PFAS-Free). "Up to" is the maker's best case. If PFAS matters to you, ask each sealer's maker what its product contains. Product-specific
As our own check, we use Laticrete's water drop on cement grout once a year: if a drop darkens the grout within minutes, it is absorbing. This manual's rule Resealing is then a question for the grout and sealer makers' instructions, which the installer can name.
Cleaning grout
Cement is alkaline, and acids dissolve it. TCNA's cleaning FAQ puts it in one line: as baking soda and vinegar react, so do grout and vinegar. It says alkaline cleaners are better than acid ones on grout, and that grout makers do not recommend acids, which can mean regrouting (TCNA, Cleaning Grout). Laticrete's premixed grout sheet lists vinegar among the acids to protect its grout from (Laticrete, pre-mixed grout data sheet, PDF). Physical principle
No vinegar, lemon or other acid on cement grout or on calcareous stone such as marble. Acids dissolve cement grout and etch calcareous stone, and vinegar on grout next to a marble tile reaches the marble too. Never mix bleach with ammonia or with acids such as vinegar; the New Jersey Department of Health's alert (PDF) explains the gases they make. Read every cleaner's label and use it as directed.
The default, then: your grout maker's or tile maker's sheet first. Where you do not have one, use a neutral cleaner next to stone (NSI) and a neutral or alkaline cleaner on cement grout next to glazed tile (TCNA), test it on a hidden spot first (This manual's rule), and rinse. TCNA's method for a deep clean is to apply the cleaner, pick up the dirty water with a wet vacuum, rinse, and vacuum again. It says to avoid oil- and wax-based cleaners on grout, because they leave a film, and to rinse even alkaline cleaners so they do not leave a sticky one. TCNA says steam may lift a stain that resists cleaners, but at least one premixed grout's sheet rules out steam, so check your grout first. Cleaning by surface has the routine, and the cleaning table has it by surface.
Corners, cracks, white residue and showers
Flexible sealant at corners and edges
Grout is rigid, and the standards call for a flexible joint where tile meets another plane. TileLetter, the National Tile Contractors Association's magazine, cites the installation standard ANSI A108.01 and TCNA Handbook method EJ171: movement joints go at the perimeter and at changes of plane, specifically inside corners, and they are filled with a flexible sealant meeting ASTM C920, often 100 percent silicone (TileLetter, flexible caulk versus grout). Many grout makers sell sealants color-matched to their grout. TCNA's materials FAQ adds that floors walked on need a harder sealant (urethane, neoprene or polysulfide, Shore hardness 35 or more), with silicone where traffic is not a concern (TCNA, Materials FAQ). Convention
So look at where the wall meets the tub, where two walls meet in a shower, and where the floor meets the wall. Press a fingernail into the joint: sealant gives a little, grout does not (that check is ours, not a standard's). A crack running along an inside corner may be grout where the standards call for sealant. Ask a tile installer to confirm and to replace it. With some stones, TileLetter says, test that the sealant does not bleed into or stain the stone before using it.
Cracked or loose grout
TCNA lists the common causes of cracked grout: a floor that flexes, joints not packed well (especially sanded grout in joints under 1/8 in.), too much water or additive in the mix, or grout used after it began to set. It calls defective grout the least likely cause (TCNA, Cracked/Loose Grout). New grout over old does not hold, by TCNA's account; a repair removes at least two-thirds of the old grout's depth first. That is an installer's job. If cracks keep coming back across a floor, the cause may be under the tile, and the installer's question is why. Ask the installer
White residue
White powder on tile or grout is usually efflorescence: mineral salts carried up by moisture moving through the slab underneath, left behind when the water dries. TCNA says it usually comes from that moisture, not from mopping water. Removing it takes acid, which grout makers do not advocate because it attacks the cement, so TCNA says a professional is best (TCNA, White Residue). NSI's advice for stone is to dust mop or vacuum it, not to use water, and to find the moisture source if it keeps coming back. A topical sealer that has turned white is a different problem with the same look. Moisture coming up through a floor is a question for an inspector, not a cleaner.
Showers: what to ask
Grout joints are not waterproof, and TCNA's steam room FAQ adds that cement grout passes water and vapor easily. In a tiled shower, the layer meant to keep water out of the wall is a waterproof membrane under the tile. TCNA's showers FAQ names two TCNA Handbook methods that put a membrane over a solid backing, says makers disagree on whether drywall is acceptable under a membrane, and says many read the building code as ruling it out in wet areas; it says to check with a local code official (TCNA, Showers FAQ). This manual does not teach shower building. These are the questions for the installer: Ask the installer
- Which TCNA Handbook method are you following for this shower?
- Which waterproof membrane, and does it meet ANSI A118.10?
- What backer board goes under it, and does the membrane's maker allow it?
- Where will the movement joints be, and which sealant fills them?
- Which grout, and what does its maker say about cleaners and sealing?
In a house built before 1978, any plan that removes old tile, adhesive or wallboard goes through Stains, damage and older homes first.
Where the sources differ Go deeper
Single-component grouts side by side
| Product | What the maker claims | What its own sheet limits |
|---|---|---|
| CUSTOM Fusion Pro (product page) | Ready to use, sanded; stain resistance with no sealing; interior and exterior, walls, floors and shower floors | Its "stain proof" line carries an asterisk pointing to the warranty |
| LATICRETE READY-TO-USE Pre-Mixed Grout (data sheet, PDF) | No sealing required; maximum stain resistance | Not for exterior use, steam rooms, pools or continuous wet areas; no acid-based or no-rinse cleaners and no steam cleaning; full stain resistance after 7 days; joints up to 1/2 in. on floors |
| Bostik TruColor urethane grout (data sheet, PDF) | Says it does not need sealing for the life of the installation; claims to exceed ANSI A118.19; stain resistance after 3 days | Read the sheet for traffic times before use |
"Single-component" is a packaging description, not one material. The three sheets agree that the grout is ready to use and disagree about where it can go and what can clean it. The product's own sheet settles it for that grout.
How often to seal
Nobody agrees. NSI's care page gives no interval and says many stones need none. In NSI's own marble article, one restorer reseals every nine months to a year and another suggests every 5 to 10 years. Aqua Mix says its penetrating sealer protects for up to 10 years. TCNA's grout FAQ gives no interval either. These figures describe different stones, different sealers and different habits, which is why the care schedule uses the water test rather than a date.
Water tests
Laticrete's drop waits 5 to 30 minutes. A restorer in NSI's granite article uses hot water for 10 to 20 minutes, and one in the marble article uses a few drops with no time given. A bead tells you the stone is sealed or dense, and Laticrete says the test cannot tell those apart.
TCNA on vinegar
Vinegar is widely recommended for grout, and one extension guide suggests cream of tartar mixed with vinegar for it (New Mexico State University, Guide G-304). TCNA says acids dissolve cement grout, and grout makers' sheets agree. The extension guide is about general household cleaning chemistry, not about tile; it also says strong acids may etch surfaces. Where the two meet a cement grout, this manual follows TCNA and the grout makers. Next to marble, NSI's acid warning settles it on its own.
Lippage
Lippage is a difference in height between the edges of neighboring tiles. TCNA's FAQ says the installation standard ANSI A108.02 defines it, and that it looks worse under raking light (light from a low window across the floor), on shiny tiles, with narrow joints and over an uneven floor (TCNA, Lippage). Tiles themselves are allowed some curve: for pavers, up to 1.0 percent along an edge and 0.75 percent on a diagonal, and the allowed lippage is the table figure plus that warpage. A percentage grows with the tile, so a long tile can carry more height difference at its edges than a small one. Before a large-format tile goes down, ask the installer how they will handle warpage and lippage, and look at a dry layout of a few tiles in the room's light.
See it: the Brennans' bathroom and Harold's See it
Tom Brennan (he/him), 44, and Alicia Brennan (she/her), 42, are fictional, as is everything about them here. They own a 1962 ranch house with their children, Nora (she/her), 8, and Eli (he/him), 5, and their dog, Juniper, a 70 lb shepherd mix. The bathroom has its original wall tile. They are choosing a new bathroom floor tile.
Known. The candidate's spec sheet lists a water absorption figure and a wet DCOF.
Assumed. They assume the floor will be walked on wet every evening, after the children's baths. Alicia assumes the candidate is porcelain because the store's shelf tag says so. That stays an assumption until the spec sheet's water absorption figure, or a PTCA mark, confirms it.
Open, and who settles it.
- Is the DCOF right for the room? Alicia reads the spec sheet: the wet DCOF is 0.42 or above, which meets the standard's interior, wet category for a level home bathroom. That settles the spec. It does not settle the tub, which the standard does not cover, so they add a non-slip mat in the tub for the children.
- Which grout, and does it need sealing? The installer names the grout; Tom writes it on the installed register with the grout maker's cleaning and sealing instructions.
- The corners. Tom asks the installer which flexible sealant goes where the floor meets the tub and the walls.
- The old wall tile and anything under the old floor. In a 1962 house, nothing old comes out until Stains, damage and older homes has been followed. The installer and, if needed, an accredited inspector settle it.
Harold Kim (he/him), 76, is fictional; the details are invented for this manual. He owns a 1988 condo with glazed ceramic floor tile in the bathroom. His daughter, June Kim (she/her), visits weekly.
Known. The tile is glazed ceramic. There is no box, spec sheet or record of the maker.
Open: is the floor slippery when wet? No DCOF is known, and there is no home version of the test, so it stays open. The answer does not wait for it. Following the CDC's checklist, June puts self-stick non-slip strips on the shower floor, and a bath mat with a non-slip backing on the tile outside the shower. Because the tile's maker is unknown, she lays the mat for a week and lifts it to check the tile and grout under it. The mat is a rug, so it should not slide or curl. Whether Harold also needs grab bars, and anything about his own risk of falling, he asks his clinician; an installer fits grab bars.
Recorded. The installed register reads "glazed ceramic, 1988, maker unknown, DCOF unknown; grout unknown, treated as cement grout". The care schedule has the yearly grout and sealant check.
Free pages that show the checks in this chapter:
- TCNA, Porcelain vs. Non-Porcelain: the 0.5 percent definition and what it changes.
- TCNA, Dynamic Coefficient of Friction: the history of the 0.42 figure and a link to the free standard.
- TCNA, Cleaning Grout: why acids and grout do not mix, and the wet-vacuum method.
- NSI, Care and Cleaning of Natural Stone: calcareous and siliceous stone, sealing and stain types.
Practice: identify, record, check the corners Practice
Minimum: one tiled room's tile type and grout type on the installed register (unknown is an answer), the corners checked, a mat or strips where someone at risk bathes, and the yearly grout and sealant check on the care schedule. Time: about 30 minutes. Materials: a flashlight, any box, receipt, invoice or spec sheet you have, a non-slip mat or strips if needed, and the installed register and care schedule (or paper).
- Name the tile. From the box, spec sheet or supplier, write porcelain (with its water absorption figure or PTCA mark), non-porcelain ceramic, or the stone and its group. Glazed or unglazed. If nothing says, write "unknown".
- Name the grout. From the invoice, bag or installer, write its type and maker. If nobody knows, write "unknown, treated as cement grout".
- Check the corners. With the flashlight, look where wall meets tub, wall meets wall and floor meets wall. Sealant or grout? Any cracks? Write what you find; ask an installer about cracked corners.
- Handle the wet floor. For a floor walked on wet, write the DCOF if the spec sheet gives it. Where someone at risk bathes, add a non-slip mat or strips to the tub or shower now, whatever the figure.
- Set the care. Tick the yearly grout and sealant check, and write your cleaner: the maker's, or neutral or alkaline with no acids. Remove vinegar from the tile caddy if it lives there.
Water test the grout or stone. On a clean, dry spot, put a drop of water about 1 in. across and wait up to 30 minutes. Write whether it darkened. For a new tile, add it to the comparison sheet with its water absorption, wet DCOF, the maker's stated area of use and the grout the installer proposes, then run the room through the quantity calculator with the maker's box coverage.
Your home Your home
Check your work Check your work
Criteria
- Does the installed register name the tile type and the grout type, with "unknown" where nobody knows rather than a guess?
- If the tile is sold as porcelain, is there a water absorption figure or a PTCA mark behind it?
- For a floor walked on wet, is the DCOF written down, or marked unknown, and is there a mat or strips where someone at risk bathes?
- Are the inside corners and the tub edge sealant rather than grout, and are any cracks written down?
- Is vinegar or any other acid off the list of cleaners for cement grout and calcareous stone?
- Does the care schedule have the yearly grout and sealant check?
Worked example
The Brennans' register has the candidate tile with its spec sheet's wet DCOF of 0.42 or above, the grout the installer named and its maker's instructions, and a question for the installer about the sealant at the tub. The tub mat for the children is on the list. Harold's register says what is unknown and treats the grout as cement grout; the strips and mat are in place and the mat's week-long check is under way. Both pass. Neither shows that a floor will not be slipped on; the standard says no figure shows that.
Common mistakes
- Taking "porcelain" on the box as the definition. Look for 0.5 percent or less by ASTM C373, or the PTCA mark.
- Reading 0.42 as "will not slip". The standard says the number does not predict a slip, and the installed floor's figure can change with wear and contaminants.
- Cleaning grout with vinegar. TCNA says acids dissolve cement grout; next to marble, they etch the stone as well.
- Sealing to stop etching. Sealer slows stains; it does nothing for etching.
- Regrouting a cracked inside corner. That joint wants flexible sealant. Ask an installer why it cracked.
- Trusting "no sealing required" without reading the grout's limits. One premixed grout rules out steam, acids and outdoor use.
What is still unresolved
Which tile to buy is your comparison on the comparison sheet; Samples, ratings, labels and warranties reads the ratings beside the others. How a floor behaves for a particular person is theirs and their clinician's to judge. Cracks that return, moisture under a floor and shower waterproofing belong to an installer or inspector. Old tile and adhesive in a pre-1978 house go to Stains, damage and older homes before anything is removed.