Grout Sealing and Regrouting Advice

Lets start my grout sealing and regrouting advice from an obvious statement. All of that can be done by non-professionals, but only it they are handy enough and do their homework really well. I wish I could say that there are tons of info online. And (unfortunately) there is! The problem is a thing called search engine optimization. See, all those websites and articles online are (usually) not written by Joe The Plumber. In the fight for Google rankings all working class heroes opt to outsource this particular part of running the business to people who actually know how to write. The problem is, that they might know how to, but haven’t got a first clue of what to write.

If you don’t want to ruin your tiles read only material from respectable sources (I’m one of them!): Aqua Mix OR Mapei. The Aqua Mix site has a whole section called “problem solvers”. Start from this bit. Other than that, CALL ME before you charge forward armed with a hammer and a screwdriver (or a wire brush).

Why do we seal grout?

Grout is an extremely porous material. The conventional cleaning methods can be more harmful than helpful in the long run. Over time, the grout body accumulates dirt and chemicals from the wastewater. This can cause permanent discoloration of the grout or even the tiles. The grout must be sealed after installation in order to keep it safe. With a protective coating, grout becomes stain-proof.

Grout sealing with our own two hands?

It depends on the age of the grout, your skills, and the type of sealer you choose. The “go ahead” scenario would look like this:
a/ The tilers completed the grout three days ago and since then no one has walked on the tiled floors
b/ You can either use penetrating sealer or clear grout sealer (providing the tiles are fully glazed, not matt)
c/ You’re handy and have some technical IQ (I can assure you that following directions on a bottle isn’t good enough).
For a beginner, fully glazed ceramic tiles are a must. Let the sealer sit for a few minutes on the grout. Than wipe all of the excess sealer away from the tiles. Leaving wet spots without wiping them turns them into white, powdery stains after the sealer is dry.

Nevertheless, it is possible to correct the mock-up. The stains can be cleaned with a product called Nano Scrub (a similar thing to Jiff or Cut’n’Polish). Nano scrub can be obtained from most tile shops. It could look even worse if you used a clear grout sealer on matt tiles. I can almost guarantee that all the tile edges would become shiny. Then, well, call the tilers before more damage is done.
Other than that? By all means, seal the grout! That’s the only way to preserve its appearance.

How about OLD grout sealing?

Not if you wish to avoid a hefty bill from the tile restoration specialist who you WILL eventually have to call. The cost of cleaning and sealing grout is relatively low, provided that there are no existing sealer coatings. A failed sealer coat cannot be painted over (clean or not). The old coat must go! The only way to remove it is stripping (the same as paint stripping). The process is slow and painful. Reacting with a stripper makes some sealers behave like chewing gum. The scrubbing brush becomes clogged after several movements. Cleaning even the dirtiest grout is nothing compared with removing some sealers.

Properly applied epoxy grout sealer can last up to 15 years. Yet I am getting calls from people asking for my help more and more often after they paid someone else for grout restoration less than a year ago! Successful sealing starts with material preparation. You cannot use a scrubbing brush to clean grout (or tiles) if you wish to apply sealer. Only the extraction method prevents wastewater from being absorbed by a substrate. It can only be done with specialized equipment.


Regrouting is only necessary if the existing grout cracks and falls out. The grout cracks for a reason. Regrouting should not take place before the root cause of the problem is identified and eliminated. The worst thing that can happen is grouting over existing grout. It is often done by amateurs and cowboy-tilers. Sadly, if done correctly, a mock-up of this sort can remain intact for quite some time.
Nevertheless, it is doomed to fail. Such a job has to be completely regrouted. Regrouting means replacing the grout, not smearing it over the existing one. Regrouting itself won’t solve any problems. If we use the same type of grout, it will crack again unless we remove the cause of cracking and use much stronger grout, often epoxy.

When you see cracks in the grout, the first thing you should do is call a tiler. Grout does not crack because it’s old. It’s not a geriatric condition. Grout can fail for a number of reasons. Customers usually think that a tiler used a non-flexible grout. This one always makes me giggle. Grout is not chewing gum. Grout can be called many things, but flexible is the last of them (regardless of what the label says). Almost half of the time, grout cracks have nothing to do with tiling. Many times it is the result of improper architectural design: too far apart floor joists, using wooden joists where metal joists should be used, floor boards of the wrong grade, wrong tiling materials specified by others.

Another common mistake enforced by architects and builders is to tile straight over butynol. It is precisely for this reason that most old decks in Auckland suffer from efflorescence and cracks in the grout. All caused by using adhesives that shouldn’t be used in wet areas, as ordinary tiling adhesive won’t stick to rubbery butynol. When your grout is cracked, a real professional should assess the situation.