Removing smeared mortar

Ask the Builder

August 10, 2008|By Tim Carter | Tim Carter,Tribune Media Services

How can I remove brick mortar from the sidewalk I just built with paver bricks? My husband and I got the mortar smeared on the brick, and it looks terrible. Is there a nontoxic way to do this?

Smeared mortar on brick is a very common problem. Depending upon the type of brick, the job can be simple or a nightmare.

Because you are concerned about the toxicity of different options, you may find it very hard to do this job. There are some pretty aggressive acids you can use, and the ones that work faster tend to be more toxic.

Bricklayers typically use muriatic acid to dissolve mortar from most brick. This is simply a form of hydrochloric acid. When you buy this product, you may notice a skull and crossbones on the label, warning you that it is a powerful chemical. However, the mortar will neutralize the acid as it works.

There are other acids that will react and dissolve the alkaline chemicals in the mortar. Even the white vinegar found in your kitchen will work to some degree. The challenge for you is to find an acid somewhere between vinegar and hydrochloric acid that will efficiently remove the mortar buildup. Consider calling a chemistry instructor at a local college or high school. You also can visit a building supply company and see if it stocks a nontoxic acid.

The first step in the process is to remove as much of the mortar as possible with a scraper or chisel.

Once the majority of the mortar is off the brick, you then should consider bathing the brick with a diluted acid solution. As mentioned above, muriatic acid is highly effective, and it works on most brick. Usually, you mix one part of the acid with 10 parts of clean water. Always read the instructions on the acid label, especially those related to safety.

In most cases, you should dampen the brick first, then try the acid solution in an out-of-the-way area if you are unsure if the acid will harm the brick. Some brick can be discolored by acids.

Use a scrub brush to help remove the mortar. Wait five or 10 minutes after the acid solution has been applied to the brick before you scrub. Rinse the brick with massive amounts of water.

Tim Carter has 20 years of experience in the home industry. If you have a question, go to and click on "Ask Tim."

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