How to seal grout on tile: A closer look

To seal or not to seal? This question has troubled most of us at one time or another. Let’s review the facts, the real facts of the grout sealing process.

Is Sealing Grout Necessary?

Any installed grout for a tile floor or wall will be one of 3 types: Cementitious, Epoxy or Furan Resin in structure. Each has its preferred environment, but none are indestructible. Also, by its very nature, an unsealed grout generally soils, stains and disintegrates rather quickly when left exposed to everyday use. Applying an effective sealer will preserve, prolong, and protect grout. This protection ultimately extends the appearance, performance, and life of any grout.

Cementitious Grout

 There are 3 types of cementitious grouts: sanded, unsanded and latex modified. Cementitious grout is composed of Portland cement, filler particles (like sand), slow curing agents and a pigment for color.

Sanded grout is mostly used where the width of the grout line is greater than 1/8”. The grout is very rough and porous.

Unsanded Grout is smoother to the touch due to the smaller particle size in the mix and is for grout joints 1/8’ or narrower.

Latex modified grout has a latex polymer added to it for strength.

All cementitious grounds are greatly improved with the application of a quality grout sealer to prevent staining, mold & mildew growth, water penetration, and premature disintegration.

Epoxy Grouts There are 2 types of epoxy grouts: Portland and non-Portland.


Portland epoxy grout is constructed using a Portland mix like the cementitious grout; thus, making it similarly vulnerable as the cementitious grout family.


Non-Portland epoxy grout does not contain any Portland mix but remains extremely vulnerable to staining and molecular disintegration due to chemical exposure.


Although epoxy grouts are more resistant to failure, both benefit greatly with the application of a quality grout sealer.


Furan Resin Grout This grout is typically found in industrial settings due to its protective characteristics and extreme cost to install, and its toxicity.


All grouts can be bolstered in performance with the application of a quality grout sealer. Ease of maintenance, improved appearance, reduced maintenance costs, and mold and mildew prevention illustrate the need for the sealing of any grout.

What is a grout sealer?

Simply stated, grout sealer is a protective layer of material that protects grout from premature wear, staining and moisture penetration. Grout sealer prolongs the efficacy and cleanability grout and preserves the structure of the longevity of grout and eliminates mold and mildew growth. Applying a quality grout sealer to grout results in a safer, less expensive, and easy to clean grout

How often do you reseal grout?

Reapplication of any grout sealer is inevitable. Let’s be honest, nothing lasts forever. With that said, let’s look at the “how often to reseal grout” question. First, we need to consider the deciding factors that create the need for resealing. The age, type, wear exposure and maintenance protocol of the grout all play an important role in assessing the need to reseal.


It is generally recommended that a reapplication of a grout sealer be completed every 18-24 mos.. Depending on the type of sealer applied and manufacturers specifications, that timeframe is objective.


There are 2 types of sealers that are recommended for the effective sealing of grout: Penetrating sealers and not penetrating.


Non-penetrating grout sealers These sealers are generally water-based and offer a more temporary protection with the understanding the process will need to be repeated on a more regular basis. These types of sealers rely on a mechanical bond (2-point) to the surface of the grout and are subject to flaking and cracking.


Penetrating grout sealers These sealers are solvent based and typically afford a longer lasting and better performing result. A covalent bond (3-point) is created to form a stronger bond at the molecular level below the surface of the grout in addition to the mechanical bond similar to the non-penetrating grout sealer.

How long for grout to dry before sealing?

Each type of grout requires a specific minimum of drying/curing before a sealer can be applied. It is necessary for the moisture to completely evaporate out and for any resins or polymers to completely bond. If the installation of the grout is new, it is important to protect the “new” grout from soiling and cracking during the drying/curing process. Consider the following guide:


Cementitious grout minimum 24 hrs. up to 72 hrs.

Epoxy grout minimum 24 hrs. up to 32 hrs.

Furan grout minimum 24 hrs. up to 32 hrs.

Considerations in choosing a grout sealer

All sealers will possess some merit. It is important the chosen sealer is right for the application in question. A careful review of the following factors for deciding what type of sealer to use will be helpful in determining what sealer is best:


– What is the goal – Interior or exterior application

– Type of grout – Age of grout

– Wet or dry area – Amount of traffic

– Residential or commercial – Cleaning protocol

– Ease of application – Environmental considerations (VOC’s)


In choosing the right grout sealer for the job, it is important to consider all possible conditions to which the sealer will be exposed. Determining the worst possible conditions can save you a lot of time and money in repairs and/or do overs.

How to apply grout sealer

The goal of applying a grout sealer is indicated by its title; consequently, we will focus on sealing the grout.


To apply any sealer to the grout only, it will be necessary to obtain the following tools:


– Witch cap squeeze bottle – Black foam paint applicator

– Clean absorbent hand towels – Solvent based cleaner

– 16 oz open container for sealer – Roller wheel sealer applicator


Fill the 16 oz. open container witch cap bottle, or the roller wheel applicator ¾ full.

When using the open container, dip the black foam paint applicator into the container and gently run the brush along the grout lines being careful not to expel the sealer onto the tile.

When using the witch cap squeeze bottle, passively squeeze the bottle while dragging the point of the cap along the grout lines being careful not to expel the sealer onto the tile.


When using the roller wheel sealer applicator, simply place the wheel of the tool onto the grout line, lightly push down on the tool while pushing forward along the grout line.


Work in an area that is easily within your reach. This will typically be no more than a 3-foot reach while on your knees. In the event some sealer is noticed on the tile, dampen an absorbent towel with the solvent based cleaner (acetone or denatured alcohol) and wipe along the sides of the grout without rubbing the grout line itself. Allow the sealer to dry before use. If a second application is necessary, repeat the process according to re-application recommendations.


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