Sealing Sanded Grout

The reason I titled this sealing sanded grout is to define the only type of grout we seal: sanded grout. Sanded grout is the rough textured grout (that contains sand) found in ceramic and porcelain tile installations. Non sanded or unsanded grout is used in natural stone floors or walls, and when it really gets dirty, it does not clean like sanded grout. Therefore, sealing nonsanded grout is pretty much a waste of time.


Grout Cleaning



Unsanded or wall grade grout is used by stone installers because 1-they typically have a narrower grout joint, 2-they could scratch a tiles surface when grouting 3- sanded grout makes a restoration using a diamond grinder difficult. It is more like caulk than cement, and dirt has an easier time penerating.Lets say you have a newly installed tile floor. Or freshly cleaned. In many cases a fresh cleaned tile floor will be cleaner than when it was new because construction residues will be finally cleaned off. The question becomes: how am I going to keep the grout from getting dirty.We now have to get into the role of a sealer, and what your options are.
Rule #1 The sealer is for the grout only. Sealers we use for marble penetrate into the stone and have no surface residue. Ceramic tiles are much harder than stone, and with virtually no porosity, they will accept no sealer. If you do get sealer residue on a tile, it will invariably attract soil, and lay on top of the tiles. Rule #2 Only use water based sealer. The reason for this is found in the application process. Solvent based sealers are manufactured to be dispensed from a solvent resistant sprayer across a broad area. Grout sealer should only be applied to the grout joint. Dried sealer on the tile will attract soil and will be clearly visible. Applicators available through retail channels all have advantages as well as drawbacks, but none we know of are solvent resistant.Rule #3 Apply to dry grout. If done after cleaning the grout need to be dried with air movers. Sealers create and oil and water repellant layer, and this is difficult to do if water is present.Rule #4 How to apply the water based sealer. As has been mentioned, sealer residue on a ceramic tile will be visible and will attract soil. The sealer is made to penetrate a porous material, and ceramic tile is not porous. Many professional grout cleaners will simply spray the sealer on the floor and attempt to squeegee into the grout joint. As you can see in the pictures below, Fabric & Tile Masters uses a commercial tool to flood the grout joint, avoiding application to the tile. Some professionals spray sealer on the tile, followed by buffing the sealer off. At least these individuals are trying to remove the excess, and for that we applaud them. Grout sealers are designed to help the end user clean up stain and spills that are dealt with promptly. The sealer should give you a chance to clean up the spill. If it is a heavy staining material like motor oil or ink, and you don't get it up before it penetrates, it will likely become a permanent stain. In 90% of homes, you walk through your garage door onto the tile and begin to clean off your feet. This cleaning will be completed on your master bedroom carpet. No grout sealer will prevent this type of soil from getting the grout dirty. Mopping, grout scrubbing, -periodic professional cleaners, and reapplication of sealer are all necessary.If you are going to hire a professional company to clean your tile and grout we recommend you find one that cleans with both an acid and an alkaline. They should also be able to detail how they seal the grout without getting sealer on the tile.

Sealing Stone Surfaces

This is an an explanation of how sealers work on natural stone counters and flooring.
Perhaps nowhere is there more bad information about maintaining a building material than there is about stone sealers. If you stand in a stone dealer showroom you will hear sales people say to each customer "yes all natural stone needs to be sealed" The question is does it really.

Backing up a few steps I would like to mention briefly just what a sealer is. Stone sealers are at a basic level a polymers suspended in either water or a solvent. The invisible polymers fill holes in the face of the stone and increase the chance of removing a spill that could possibly permanently stain the stone. These sealers are then applied to the stone surface where ultimately they penetrate into the porous stone, filling microscopic (and some not so microscopic) holes. When applied correctly the desired outcome is a stone surface that has increased surface tension and decreased absorbency. The sealer then offers the stone some water and oil repellency.

Grout Cleaning



The variables involved in application of a sealer:

The suitability of the sealer for the job. Let’s say you apply an acrylic floor sealer to a stone floor. The stone wont even resemble what you picked out in the first place and you are going to have to speak with a guy like me to restore it. A proper stone sealer under all circumstances will be invisible on the stone surface.


The suitability of the stone for the sealer. Many stones, regardless of the finish (honed or polished) will not take a sealer and it will sit right on top of the stone surface. An absolute black granite with a honed finish will not take a sealer, nor will a polished creama marfil.

The condition of the stone immediately before application of the sealer. Many times sealers are used to cover scratches and grout haze from an instillation. What can I say, it happens. Call me.


Some sealers work better than others. A solvent-based sealer will work better than a water based sealer. There are also enhancer sealers that can add to the depth of color of some stones. They can change the way a stone looks, but applied properly you will not see the sealer or residue on the stone surface.

Sometimes because of the intended use of the stone, you really need a sealer (honed finish in a kitchen with lots of kids and a dog) and sometimes (a polished finish marble with two retired people who remove their shoes at the door) you don’t.


So the variables are the applicator, the sealer, the stone and the traffic.
Go over these carefully with your stone pro to be sure you are getting what you need. If you are a doityourselfer, follow the guidelines listed in this blog for proper sealer application.



Remember too, no sealer will keep the floor from getting dirty. Look to the maintenance guidelines listed on this blog for guidelines. Sealer objective is to give you a little time to wipe up an oil or water based spill before it penetrates into stone.

To test if your stone needs a sealer, drop some water on it and if it darkens, it probably needs sealing. The only rule I know that applies to all sealers and all stone is to test in an inconspicuous area to see how it will look. When you are satisfied you will be happy with the way it looks go ahead and seal away.

sealer applied to granite. notice water beading due to increased surface tension.
stone enhancer applied to slate. BTW we used respirators during this application.
water beads on sealed granite

sealer beads up on right, and lays flat on unsealed left

Stone Acid Etchings

In my previous post I mentioned the necessity to avoid acid etching. Low ph solutions like cola, fruit juices and a multitude of household chemicals will cause acid etchings. We have to use a floor machine or an angle grinder to remove these etchings, a process that can be quite expensive. Shower walls for example are usually billed $500 per wall. The reason it is so expensive is that many times each square inch of every tile will need to be exposed to a grit progression (100,220,400,800) and then will be polished to achieve a like new finish.
These are a few pictures of etchings being repaired.
Breccia oniciata etched with a heavy acid. See streaks on the right. The tile on the left has been refinished.
The ceiling of this bathroom was sprayed with tilex cleaner. You can see the white etch marks on the tile.


Grout Cleaning