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Removing adhesive mortar from brick fireplace

Hello all!
My husband and I recently purchased a home built in 1927. The fireplace's original brick was covered (by a misguided "flipper") with 12X12 porcelain tiles. The tiles were laid directly over the brick using mortar as adhesive.

We've been successful in hammer/chiseling off the tiles, but there is a substantial amount of mortar adhesive residue left behind. Because it filled into the surface of the bricks, it will be impossible to remove entirely through hammer and chisel.

Any tips on a chemical application (store bought or homemade) that might assist in our efforts? I also, of course, will need to be careful as we do not want to compromise the integrity of the "good" mortar that the brick is set into.

Many thanks!

Courtney Hogan-Stanzione
consumer - Somerset, New Jersey
2007

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Flippers have wrecked a number of houses in our neighborhood and tricked a few of people to make their fast bucks. The "standard" thing for removing mortar is muriatic acid ⇦ this on eBay or Amazon [affil links] , but it is hazardous (it's a strong acid) and, unless you prevent it, the fumes will travel through the house and rust any stainless steel or chrome. You might try it, wearing rubber gloves ⇦ this on eBay or Amazon [affil links] and goggles ⇦ this on eBay or Amazon [affil links] , and with good ventilation, on a small area and see what you learn. Good luck.

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
2007

If you use muriatic acid inside, start out with a dilute solution and add acid to that solution until you find the one with the fumes vs speed that will work. I would start with pool acid at 10% with water at 90% as a beginning point.

James Watts
- Navarre, Florida
2007

Courtney,
Why mess around with acids and other stuff that may or may not work when sandblasting is the obvious least drastic answer. Sandblasting isn't that old time huge compressor, lots of noise activity any more. Look in the Yellow Pages or go on the Internet under "Sandcarving" and you should find a person with a small commercial unit that can come to your house and make the mortar (GLUE) disappear.
If you can't find anyone suitable try melting the adhesive with acetone ⇦ this on eBay or Amazon [affil links] Warning! highly Flammable! or lacquer thinner ⇦ this on eBay or Amazon [affil links] Warning! highly flammable! (both STRONG FLAMMABLE DANGEROUS solvents requiring maximum ventilation) Buy a pint or quart of either (I suggest lacquer thinner ⇦ this on eBay or Amazon [affil links] Warning! highly flammable! ) and put some on a rag and just hold it on the affected area. You will be able to tell within a minute or so if the solvent will do the job by softening the glue. BE CAREFUL THESE ARE HEAVY DUTY SOLVENTS!

Stephen Mann
- Palm Springs, California, USA
2007

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The National Park Service's Technical Preservation Services has Preservation Briefs and Preservation Tech Notes, some available on-line: http://www.nps.gov/history/hps/freepubs.htm

Conventional sandblasting may damage bricks, many of which have a dense glazed surface and porous interior. Using softer abrasives such as glass beads or walnut shell media ⇦ this on eBay or Amazon [affil links] may work, as may high pressure water jet cleaning. If mastic adhesive was used, dry ice blasting may work better.

Ken Vlach [deceased]
- Goleta, California
Finishing.com honored Ken for his countless carefully researched responses. He passed away May 14, 2015.
Rest in peace, Ken. Thank you for your hard work which the finishing world, and we at finishing.com, continue to benefit from.
2007

We just removed old 1970's lava rock from our fireplace. We were successful in moving most of the concrete that was holding the rock on the floor to ceiling fireplace...however, we still have large patches we need to remove. The brick isn't brick underneath it is almost concrete shaped bricks. We have noticed in some spots they are cracking. Should we halt the chiseling? Another way to remove?

Donna Cleary
- San Diego, California
August 28, 2010