CTEF Tile Tip
Acid Effects on Cement Grout
These low grout joints result from acidic cleaners being used on cement grout joints. The litmus paper and distilled water test clearly show the reddish-orange indication of acidic cleaners. Photo: Scott Carothers
Commercially manufactured cement grouts work well and meet the needs of tile installations. These grouts fill the spaces between the tiles, producing a sanitary finish. They offer over 40 colors, which gives the end user unlimited design possibilities and provides a smooth transition from tile to tile. When correctly maintained, the results are long-lasting.
A Chemistry Lesson
In order to have longevity, however, cement grouts need to be properly maintained. If you recall your high school chemistry class, neutral pH is 7. Anything above 7 is basic or alkaline and below 7 is acid or acidic. Acids range from the strongest pH 0 (zero) hydrochloric acid, stomach acid, battery acid, vinegar, orange juice, tomatoes, coffee, potatoes, to cow’s milk which is the weakest acid. In the middle of this spectrum, pH 7 is neutral and includes pure/distilled water. Basic or alkaline products ranging from the weakest to the strongest include eggs, baking soda, hand soap, milk of magnesia, ammonia, bleach, and drain cleaner/lye at 14.
Interestingly, the pH of Portland cement products, which includes Portland cement grouts, ranges from 11 to 13 making them exceptionally durable. But being highly alkaline, cement grouts are affected by products on the other side of the pH scale, namely acids.
The Problem
Unfortunately, some folks--both tile installers and consumers--believe that using acid is the best or only way to “clean” cement grout, but this thought is completely wrong and makes the grout more porous. This porosity provides additional opportunities for dirt and other contaminants to fill that space; hence, they gather soil more quickly. On the chemistry side, when acids are used in this way, they lower the high pH of cement grout, making it weaker and susceptible to further deterioration. Consistent use of acidic cleaners compounds the problem.
Similarly, exterior tile installations can be affected by acid rain and degraded. When the rainwater is absorbed into the grout and eventually evaporates, the acid lays dormant until it becomes wet again. The newly applied water activates the acid crystals in the grout, causing further degradation. In cold climates, this action is exacerbated by using salt compounds to melt sidewalk and driveway ice, providing walking safety. This combination of acid rain and salt drastically reduces the pH of the grout causing it to weaken and decay.
The Solution
Rather than use acidic cleaners that do not actually clean the grout, use a pH-neutral cleaner which works well for routine cleaning schedules. These products are normally available at tile distributor locations, in some box stores, and online.
Be cautious of cleaners that say the product is a “heavy-duty” stripper which most times is highly alkaline. These products have a specific use but should not be used routinely. If grease and oil buildup are present on the cement grout, use an alkaline cleaner just long enough to eliminate the problem and always rinse with clean water as the manufacturer directs. At this point, return to the pH-neutral cleaner for routine maintenance.
Lastly, always read the product label and the website product data sheets to determine the product's chemical composition to determine if it is appropriate for your cleaning goals before using it.
This article was originally posted on www.floortrendsmag.com.
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