The mortar that smears onto brick is a common problem. That’s unfortunate because usually, it indicates sloppy work quality. People want to find ways to remove mortar to give their stones or bricks neater lines and a cleaner finish.
That, or you’re interested in removing mortar that’s on older stones and bricks you plan to repurpose or renovate in some fashion.
Mortar’s a sticky, hard substance. After all, it’s designed to bind mason work together strongly. It wouldn’t be worth trying if it just came off by spraying it down with a hose.
The mortar that’s smeared onto bricks usually happens when masons are in a hurry. Maybe they figure no one will see that part of the home or office building, so don’t pay as much attention to detail. Either that or you’re a budding DIY mason trying yourself and you tend to get too much mortar on everything.
No worries. Following these steps will help you remove unsightly mortar and get you the shining brick face you want on your wall or chimney.
Step 1 – Make Sure You Have Appropriate Safety Gear
Removing mortar involves applying muriatic acid to the brick and mortar work. Muriatic acid is the strongest cleaning solution you can buy over the counter in the U.S., so you’ll want to make sure you’re wearing gloves, safety goggles, and long-sleeved clothes and pants. Always wear boots or some other closed-toe shoes in case anything spills.
Make sure anyone in the vicinity is also wearing the same. Just because you’re the one handling the muriatic acid doesn’t mean that accidents don’t happen or someone, like a child watching you, can be careless.
Before you start, put some thought into what you’ll do with the acid after you’re done with your project. You may need to do your work in stages, so ensure you have a safe place to store the muriatic acid that’s out of reach and won’t hurt anyone or cause property damage.
Step 2 – Create the Muriatic Acid Solution
The solution that cleans mortar of brick and stone is made by mixing water and muriatic acid.
*A friendly reminder. Never pour any acid directly into a plastic container. It will likely melt it. Avoid this by first pouring the right amount of water into a container and add the acid to the water.
Most muriatic acid containers will have instructions on the container that explain what ratio of water to acid that you should follow. Typically, it’s one-part acid to 10 parts water.
UPDATE – We have learned that it is best to buy a ready made solution for cleaning bricks and not try and mix muriatic acid yourself as you have a chance of pouring the wrong amounts and effectively damage your brick
Step 3 – Prep the Work Area
After the solution’s made, you’re ready to go. Just grab a bucket with plain water and place it nearby. You’re going to use the clean water to scrub the mortar once the acid’s had time to work.
Step 4 – Apply the Cleaning Solution
Once you’re ready, apply the muriatic acid solution to the stone or brickwork that you need to clean. You can get it on the mortar with a brush or sponge. When the solution is on, the mortar will start to bubble and foam a bit. You may hear some fizzing noise as well.
Let the solution rest on the mortar for several minutes before you do anything. It needs to sit and start breaking up the mortar so it can be removed. Usually, this takes anywhere from five to ten minutes.
If the mortar isn’t coming off at all, or there’s no bubbling or fizzing, that means your solution is likely too weak. There’s not enough acid to break down the mortar and remove it from the stone. You need something stronger. You can mess with the solution by adding a bit of acid bit by bit until you get the desired result.
Step 5 – Scrub the Mortar
When the time is up, use a bristle brush to start scrubbing off the mortar. Each time you scrub, first dip the brush in the clean water container. The mortar should crumble off the stone or brick wall fairly easily. If it’s still stuck, apply more solution, wait the five minutes, and then try scrubbing again.
Make sure to dip your brush in the clean water container frequently. You don’t’ want too much acid solution to build up.
If the brush isn’t getting the mortar off the stone, you can try using a scraper. Just be careful, though, because you can scratch the stone or brick surface with a metal scraper. Any time you use a scraper, make sure you have flowing water running over the mortar and surrounding bricks. It will make scratches less likely.
For extremely stubborn mortar, use a scraper and a hammer together. Place the scraper at an angle and tap the handle gently with the hammer. Add strength to the taps slowly until the mortar cracks and breaks free.
Step 6 – Wash Up
Once the mortar you want to be taken off is removed, you can wash the entire masonry surface down with a hose. Using the hose will get enough water onto your brick or stonework that it will dilute the acid even further, so it won’t hurt anything if it’s left on the masonry work.
Take a step even further by rinsing down the wall or structure one more time with an ammonia-water mixture that neutralizes the acidity of the muriatic acid solution. Normally, you can mix one cup of ammonia with each gallon of water to get the right ratio that works.
Don’t keep the containers or brushes for future use. The acid is strong enough that you won’t want it sitting around your house or commercial property any longer than it has to. Once you’re done with them, wrap them in plastic bags and throw them away.
Following these steps will help you have the stone or brickwork that every homeowner expects. Don’t settle for messing mortar that looks dreary and sloppy. Removing mortar from stone is relatively easy, so give it a try. Soon, your masonry work will look good as new, and your property will be better off for it.