Tile and grout: Tough problems, simple solutions

Oh, that awful dirty grout; you’ve tried everything and it just refuses to come clean.

Most grout becomes soiled by grease and water-based stains.

In order to remove dirt, it needs to be cleaned with two different cleaners: One to remove grease and oil and the other to remove water-based soil.

The secret recipe

The following is my secret recipe for cleaning grout. You will need two chemicals — sulfamic acid and a good wax floor stripper.

Sulfamic acid can be purchased at most home centers and can also be found at tile supply companies.

An alkaline-based floor wax stripper can be found at your local janitorial supply house.

The process

  • Sweep the floor thoroughly, removing any loose dirt, dust, etc. For showers and walls, wipe with a dry rag.

  • Mop the floor with warm water and a good floor cleaner, or ammonia. Use a clean rag and the same chemical for showers and walls.

  • Mix a solution of the alkaline stripper and warm water in a bucket, making sure to follow the directions on the bottle.

  • Apply a small amount of this solution to the grout. Allow it to stand for several minutes and agitate with a scrub brush, toothbrush or similar type tool. Apply additional solution if it begins to dry.

  • Pick up excess solution with a mop or a wet-vacuum.

  • Rinse the grout with plain warm water.

  • Mix a solution of sulfamic acid with warm water per directions on the label.

  • Apply the acid solution to the grout and agitate.

  • Rinse the grout several times with clean water and allow to dry overnight.

  • Once dry, seal the grout with a good, penetrating sealer.

If the above technique does not work, the grout will either need to be removed and replaced, or, if the grout is sound and not falling apart, it can be re-colored.

Note of caution: Sulfamic acid will damage marble surfaces.

Removing and replacing grout

If you need to remove and replace grout, don”t worry. The process is not that difficult, but it requires a little patience and know-how.

Here is your know-how, but you will need to supply the patience, and the elbow grease!

You will need the following inexpensive tools:

  • A hand held grout saw, which can be purchased at most home centers, hardware stores or tile supply houses for a few dollars.
  • A grout float, which also costs only a few dollars. I prefer the type with the rubber face, but any grout float will work.

Getting out the grout

Remove the grout by working the grout saw in a back and forth motion until you have removed more than half the grout.

It is not necessary to remove all the grout, as long as you remove about one-quarter of an inch, minimum.

Once the desired amount of grout is removed, vacuum all the grout and dust from the floor or wall.

Now, check for loose tile and reset these before re-grouting.

The next step: Replacement

It is important to choose the proper grout.

For walls and grout joints one-eighth of an inch or smaller, use un-sanded grout.

For floors and grout joints more than one-eighth of an inch, use a sanded grout.

Be sure to use caution when grouting marble tile, as unsanded grout can scratch the surface.

Place the grout in a bucket, add water and mix into a thick, smooth consistency (not too soupy).

Add more dry grout powder if the mixture has an excessively soupy texture.

Some grout needs to sit several minutes and then be remixed before using. Check the manufacturer”s directions.

Now, apply the grout with the grout float and work it into the joints, making sure they are full.

It helps to pack the grout into the joints by pressing hard on the grout float.

Once all of the grout joints are full, hold the float at a 45-degree angle and move it diagonally across the grout joint to remove excess.

It”s best to work in small sections so the grout doesn”t dry too quickly.

Once all tiles are grouted, wipe the whole surface with a clean, wet sponge. It will be necessary to rinse several times.

I prefer using two buckets and two sponges, but be sure to change the water often.

Allow the grout to sit at least 24 hours.

Occasionally a light film will be present after the grout dries. Remove it by buffing with a clean, dry cloth.

Avoid walking on the floor or using the shower for at least 24 hours.

Sealing grout

In order to keep your new or newly cleaned grout pristine, it should be sealed.

There are so many sealers on the market today. Which ones are best? Which ones really work?

It can be very confusing trying to choose a sealer to protect grout; in the past several years, hundreds of products to seal and protect grout have flooded the market.

Fortunately, all of these products fall into two major categories:

  • Coatings
  • Impregnators, or penetrating sealers


Coatings are sealers that place a sacrificial coating on the surface of the grout.

This film lies on top of the grout, acting as a barrier to prevent water, oil and dirt from entering the pores.

Coatings can be classified into two general types:

  • Strippable
  • Permanent

Strippable coatings are designed to be easily stripped or removed from the surface of the grout.

These coatings are made from polymers consisting of acrylics, styrene, polyethylene and others, and are usually water-based.

Many janitorial products are water-based, polymer-type coatings. To identify these coatings, look for terms on the label, such as, “metal cross link”, “high solids”, “high speed”, “acrylic”, “thermoplastic”, etc.

When in doubt, ask. There are hundreds of different strippable coatings.

Permanent coatings are very difficult to remove.

Made from solvent-based polymers, such as polyurethane, epoxies, etc., they are not recommended for grout.


Impregnators are designed to penetrate below the surface of the grout and deposit solid particles into the pores or coat individual minerals below the surface so water, oil and dirt are restricted from entering.

Impregnators can be solvent- or water-based and usually contain silicone, siloxane, silane, methyl silicate, or other similar silicon derivatives, as well as Fluro alphatic polymers.

Impregnators can also be classified into two types:

  • Hydrophobic, or water repelling
  • Oleophopic, or oil repelling.

Hydrophobic impregnators are designed to repel only water and water-based chemicals, such as, fruit drinks, coffee, tea, soda, etc.

Oleophobic impregnators are designed to repel water and oil-based liquids, such as, cooking oil, grease, body oils, etc.

An oleophobic impregnator will always be hydrophobic, but a hydrophobic impregnator may not be oleophobic.

Be sure to read product labels carefully to determine if they are hydrophobic or oleophobic.

Use caution as some products are listed as oil resistant, but are entirely different from oil repellant.

Oil resistant products will only slow down the absorption of oil into the grout; oil repellant products will prevent oil from entering the grout.

Again, read product labels carefully and be sure you are buying the right product for your particular situation.

Sealing grout with an impregnator

Clean the grout thoroughly with a good grout cleaner or use the procedure described above; allow the grout to dry thoroughly.

Pour a small amount of sealer onto the floor and spread with a string mop or lambs-wool applicator.

For showers and walls, use a terrycloth rag to apply the sealer.

Allow the sealer to penetrate into the grout for several minutes and apply additional sealer if needed.

Once all the sealer is applied, buff any remaining sealer from the tile with a dry cloth.

If you are sealing a large area, a floor machine may be used.

Try to avoid spilling anything on the grout for several days as some sealers take this long to cure.

You can, however, walk on the floor once it is buffed.

Sealing grout with coatings

Once again, clean grout thoroughly and allow to dry completely.

Apply the sealer with a small brush or applicator (some sealers come with a self-dispensing applicator).

Work in small areas and avoid getting sealer on the tile.

Keep a clean rag handy in case you accidentally get some on the tile.

Allow the sealer to dry thoroughly before walking on the floor or using the shower.

As you can see, this procedure is very time consuming. I prefer sealers that penetrate for this reason.

Coloring grout?

Yes, it is possible to change the color of your grout without replacing it.

Coloring grout will also seal it, preventing it from soiling. Grout coloring can be purchased at most home centers and tile supply houses.

Before you can color your grout, you must clean it and perform the following test to make sure the grout coloring will stick and not peel.

  1. Clean about one foot of grout using the previous grout cleaning procedure. Dry the area with a hair dryer or heat gun, and make sure the grout is thoroughly dry.

  2. Apply a small amount of grout coloring with a paintbrush to the cleaned area. Dry the grout coloring with the hair dryer, and leave overnight if time permits.

  3. Once the color is dry, take a piece of masking tape and apply it to the grout color. Rub the tape with your finger to make sure it sticks to the color.

  4. Quickly remove the tape. If the grout coloring sticks to the tape, then the chances are the color won”t stick. In this case, you will acid wash the grout and repeat this test. If the coloring remains on the grout, you can proceed with the coloring.


Apply the grout coloring to the grout with a small paintbrush or applicator.

Do not apply too heavily; it is better to apply two thin coats than one heavy coat.

An airbrush can also be used to apply grout coloring.

Don”t worry about getting color on the tile. It should clean off easily from ceramic tile.

Marble, granite and stone may pose a problem when trying to remove the color. Check to make sure the grout coloring does not absorb into the stone.

If it does it you may have to mask off the tile with tape.

Allow the coloring to dry (see label instructions for dry times) and then remove excess coloring from the tile surface with a green scrub pad and some warm water with dish detergent.

If any coloring is removed, you can touch up later.

The process is quite simple, but remember: It is important to remember to relax and take your time.

Grout maintenance

To keep your grout looking new, use a neutral cleaner. It”s best to avoid harsh chemicals.

A neutral cleaner is neither acid, nor alkaline; it has a pH of 7. Neutral cleaners can be purchased from most janitorial suppliers.

It is especially important to use mild cleaners with colored grout as coloring will eventually come off and will require reapplication.


Posted On September 19, 2010

Frederick M. Hueston

Director of the National Training Center (NTC) for Stone & Masonry Trades

Frederick M. Hueston is the director of The National Training Center (NTC) for Stone & Masonry Trades and is an internationally-known consultant who deals with stone and tile problems. For more information on Hueston and the NTC, visit

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Tile and grout: Tough problems, simple solutions
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