All About Tile Grout and How to Clean It

The purpose of grout

Nobody pays attention to grout when it does its job to lock tiles tightly, keep out water, and give floors and walls a finished appearance. People only notice stained, cracked or missing grout altogether when it fails.

But grout deserves more respect. The grout contractor on This Old House’s Nantucket tile project, David Goodman, says that grout fills the voids and makes the floor, wall or countertop stronger by bonding tiles together and protecting edges from chipping and cracking.

This article will cover everything you need about grout, including the types and colors available and how to repair them.

Cement-based Grout

There are two types of grout. The choice of which type to use is determined not by the size of the tiles, but the distance between them. Unsanded grout is best for narrow joints less than 1/8 inches. It’s a pudding-smooth mixture of Portland cement and powdered colors mixed with water. Sanded grout is used for joints larger than 1/8 inches. This grout contains the same material but with more sand. The grout is bulked up with sand to prevent it shrinking in joints.

Goodman recalls that when he first started the business in 1983, “we just added powdered grout and a bucket of hot water and we were good to go.” Older cement-based grouts were brittle and susceptible to cracking. The grout also dried unevenly, making colors inconsistent. Today’s grouts are made with polymer additives that ensure color quality and greater flexibility. They can have joint widths up to 1 1/4 inches. These wide joints are useful for hiding irregularities in handmade tiles or bridging differences in tile thickness in patterned installations.

However, cementitious grouts can stain, despite their superior performance. Manufacturers and installers recommend sealing grout once it has dried completely and cured for a few days.

Grout Sealers

There are two types of grout sealers: penetrating and membrane-forming. The first is more prone to cracking and clouding due to moisture from underlayments or mastic. These sealers are better for tile and grout that can still breathe, such as penetrating sealers.

Goodman will sometimes encourage customers to seal grout their own to cut down on labor costs. I give them some cotton swabs and a disposable toothbrush, and ask them to finish the job.

Epoxy Grout

Some situations, such as those exposed to acids or greases, can make even an additive-enhanced sealed grout ineffective. Epoxy grout is required for these harsh conditions. Epoxy grout is made up of two components, resin and hardener. It is waterproof against most chemicals and stains and can be sanded or unsanded. The pot life of early epoxies was only 45 minutes. They were difficult to apply and unforgiving. They were fast to cure, but difficult to accept by tile setters. This was a major problem for beginners.

New generation epoxies include detergents in their hardeners. This allows for easy cleanup with water and increases workability. Epoxy can stain porous surfaces such as limestone and unglazed quarry tiles. This should be sealed before grouting. Epoxy grout is a great choice for floors, countertops, backsplashes and kitchen counters.

Epoxy Grout is more expensive

Although epoxy grout can be more expensive than cement-based grout at $8 per pound (compared to $1 to $2 for cement grout), there are some upsides to this cost difference. Powdered Portland cement grouts last only one year while liquid epoxies will last forever if not exposed to freezing temperatures.

Grout Colors

There are three options for grout colors: contrasting (e.g., black grout with black tiles), harmonizing, green grout with green tiles, or neutral (a color that is either gray or white). David Goodman advises his clients to avoid choosing a striking combination. He says that while you may not love gray, it is unlikely that you will hate it.

You can grout a small tile section on plywood to test the bold color and then live with it for several days. Goodman states, “I advise people to view the color in many different lighting conditions — natural, incandescent and fluorescent.” Unsealed cementitious grout that has been cured can be stained or painted if you make a mistake. Epoxy grouts or sealed grouts must be removed. Goodman states that it can be a tedious process so why not make the right decision the first time.

Grout Cleaning Solutions

Dark grout can be left behind by years of grease and food stains. In extreme cases, retile or regrout may be necessary. However, most grout can be renewed. You will need a degreasing product, a stiff-bristle toothbrush or commercial steam cleaner, elbow grease, and elbow grease. Spot regrouting is necessary. This involves removing and replacing any areas that are cracked or broken.