Grout is the cheapest part of any tile job and the part most likely to fail first. Pick the wrong formula and you get cracking in shower corners within 18 months, mildew that bleach cannot kill, and color shifts that turn a $4,000 bathroom into an eyesore. The four main types of grout — sanded cement, unsanded cement, epoxy, and single-component urethane — each solve different problems, and the choice depends on joint width, location, traffic, and how much hands-on maintenance you are willing to commit to over the next decade.
Part of our Tile & Grout guide — explore the full guide →
Sanded Cement Grout
Sanded grout is the workhorse of residential tile. Portland cement, fine silica sand, color pigment, and water — that is the entire formula. The sand acts as a structural filler, keeping the grout from shrinking and cracking as it cures. Use it anywhere the joint width is 1/8 inch or wider, which covers most floor tile, subway tile installed with 1/8-inch spacers, and outdoor patio work.
Cost runs $15 to $25 for a 25-pound bag, enough to grout roughly 100 square feet of standard floor tile. Major brands include Custom Building Products Polyblend, Mapei Keracolor S, and Laticrete Permacolor. All three offer 30 to 60 standard colors plus custom matching.
The downside is porosity. Cement grout absorbs water, oil, and pigments unless sealed. Plan on applying a penetrating sealer like Aqua Mix Sealer’s Choice Gold within 72 hours of grouting, then again every 1 to 2 years for floors and every 3 years for walls.
Unsanded Cement Grout
Unsanded grout uses the same cement and pigment base but swaps sand for a polymer modifier. The result is a smoother, stickier mix designed for narrow joints from 1/16 inch to 1/8 inch wide. Unsanded is the right choice for polished marble, glass mosaic, and metal tile because sand grains can scratch soft or polished surfaces during installation.
It is also preferred on vertical walls. The polymer makes it cling without sagging, so backsplash and shower wall jobs go faster. Cost is similar to sanded — $18 to $30 per 10-pound bag.
Limitations are real. Unsanded grout shrinks more during cure, which is why manufacturers cap it at 1/8 inch. Push it into wider joints and you get hairline cracking by year two.
Epoxy Grout
Epoxy grout is a different chemistry entirely. It mixes a resin and a hardener, sometimes with colored sand added, and cures by chemical reaction rather than evaporation. Once set, it is nearly impervious to water, oil, acids, and household chemicals. Showers grouted with epoxy still look factory-fresh after 15 years with zero sealing.
Brand leaders are Laticrete SpectraLOCK Pro Premium and Mapei Kerapoxy CQ. Expect to pay $80 to $130 per kit, which covers around 50 to 75 square feet — roughly four times the cost of cement grout per square foot.
Working time is short, usually 45 to 80 minutes from mix to unworkable. The haze cleanup is brutal: epoxy that dries on the tile face requires a special acidic cleaner and aggressive scrubbing within 24 hours, or it stays forever. Most DIYers underestimate this and end up paying a tile setter $400 to $600 to clean up the mess.
Single-Component Urethane Grout
Urethane grout, sold premixed in plastic buckets, is the newest category and a compromise between cement and epoxy. It is stain resistant like epoxy, flexible enough to handle minor substrate movement, and applies almost as easily as cement grout. Open the bucket, scoop out what you need, and replace the lid — the unused portion stays usable for 12 to 18 months.
Bostik TruColor and Mapei Flexcolor CQ dominate this segment. A 1-gallon pail covers 100 to 150 square feet and costs $55 to $85.
The main weakness is heat tolerance. Urethane grout softens above 140 degrees F, so manufacturers warn against using it in steam showers, saunas, or anywhere subject to direct sun heat through glass. Standard residential bathrooms and kitchens are fine.
Specialty Grouts and Where They Fit
A few niche formulas show up in specific applications. Furan grout is for chemical plants, breweries, and food processing — almost never residential. Caulk-style grout in matching colors is sold for changes of plane (where wall meets floor or two walls meet), because rigid grout cracks at any flex point. Always use matching color caulk, not grout, in inside corners and around tubs.
Glass-specific grouts like Laticrete Glass Tile Premium are non-staining and non-yellowing for translucent mosaic backsplashes where standard grout would cloud the glass.
Choosing the Right Type for Your Project
For kitchen floors and entryways, sanded cement grout sealed annually delivers 80 percent of epoxy performance at 25 percent of the cost. Bathroom floors and shower walls are where epoxy or urethane earn their premium — water exposure is constant and re-sealing cement grout in a wet shower is impractical.
Backsplashes can use any of the four types of grout. Most homeowners pick unsanded cement for narrow joints with glass or stone, or urethane for kitchens where grease splatters. Outdoor patios demand sanded cement plus a high-quality sealer because epoxy and urethane do not handle UV exposure long term.
Tools and Tips for Application
- Float: Rubber float at 45 degrees for application, harder rubber for haze removal
- Sponge: Hydrophilic tile sponge — never a household sponge, which leaves lint
- Buckets: Two — one for sponge water, one for clean rinse water
- Timing: Wait 24 to 48 hours after thinset cure before grouting; honor the bag instructions
- Sealer: Apply 72 hours after grouting for cement; not needed for epoxy or urethane
One last pro tip: order 15 percent more grout than the calculator suggests. Color matching a partial bag in the middle of a job is nearly impossible, and the difference between two production lots can be visible across a single shower wall.
