How to prevent shading in grout

Author: DCOCF Marketing, March 28th, 2022

How to Prevent Shading in Grout


This month, DCO Commercial Floors is proud to have one of our vendor representatives educate us on how to prevent shading in grout. When it comes to a smooth installation, it’s important to know all the ins and outs of what can happen if a product isn’t used correctly, and how to prevent a failed installation. Mike Glass at Mapei gives us some insight on how to prevent shading in grout, and how to make sure your next installation is successful.

For every tile installation, it’s been said “Grout is 10% of the job and 90% of the headache.” This has historically been very true about cement grout. But with new technology in the industry, grout problems can be minimized if not eliminated. Let’s take a brief look at some common causes of inconsistent shading in cement grout and how to combat these issues.

Cause # 1 – Not dry blending the powder grout before mixing

Because the pigment is the lightest weight material in the dry powder mix, if you only mix partial bags and not full bags, you risk using too much or too little pigment in that pail of grout. To avoid this problem, either mix full bags or at least dry blend the grout before adding water will help disperse the pigment evenly.

Cause # 2 – Too much water in the mixing and cleaning process

Too much water in the mixing process will dilute the grout pigment causing inconsistencies. Furthermore, using too much water in the cleaning process will also dilute the grout pigment. To avoid this problem, use the recommended amount of water by the manufacturer for mixing the grout. Also, use only a clean damp sponge to clean the grout off the tile while avoiding excess water in the joints.

Cause # 3 – Begin the initial cleaning process too soon

Again, because the pigment is the lightest weight and remains more concentrated on the surface of newly installed grout joints, it can be wiped away and diminished if not enough time is allowed for the grout to settle in the joint.  This can cause inconsistent shading of the grout.  To avoid this problem, allow enough time for the grout joints to settle (20 min.) before the initial cleaning is attempted.

Cause # 4 – Tile mortar too high in the grout joint

When the tile installation is complete, sometimes tile mortar can fill up a large portion of the grout joint. When this occurs and the grout is installed, the raised mortar can cause inconsistent shading in the grout appearance.  To avoid this problem, make sure all mortar is cleaned out of the grout joints before installing the grout.

Cause # 5 – Using lesser quality grout

Because today’s grout joints are smaller and tile is bigger, this is the time to use better grout products that minimize or eliminate inconsistencies in grout performance. Portland Cement grout is “by nature” problematic. Even if the installer does everything right, Portland cement grout can still have shading issues. Because so much of the inconsistency is related to pigment and water interaction, you reduce those issues when you use a calcium aluminate cement grout (MAPEI Ultracolor Plus FA grout). Calcium aluminate grout “burns off” 40% of the excess water internally and reduces the risk of pigment dilution. You can even further eliminate all grout issues with shading by using a RTU “ready-to-use” acrylic grout that has no loose pigment at all (MAPEI Flexcolor CQ grout).

To learn more about Mapei’s products, click here,

To reach out to our Mapei representatives, email:, or

To read more about women in construction week, and it’s history, click here. 

About the firm: DCO Commercial Floors is a nationwide flooring dealer that is committed to being a flooring solutions leader for all finishes, bridging the gap between traditional floor covering and modern access flooring solutions. We provide comprehensive project management so that your project is smooth from the estimating stages to breaking down the bid, and procurement, from install to closeout. DCO will provide and deliver on all facets to become the partner of choice for your project.