Removing Paint from Vintage Masonry
Let Your Home Love the Skin It’s In!
Put down that can of white paint—that limestone is already the perfect color! Bedford limestone, which is responsible for so many of our building foundations and decorative details in Chicago, came right out of the quarry with that handsome gray tint! Limestone comes in a variety of colors, and our local stone from the 1910s and 1920s is its own unique color, hailing from Bedford, Indiana.
You won’t want to paint your historic brick either! Painting over any vintage masonry causes unnecessary harm to your home.
If you’re considering painting your bare limestone because it looks a little dirty from pollution stains, you can clean it with a limestone cleaner. Most masonry restoration experts recommend products made by PROSOCO. As a general rule, always start with the “weakest” product first because there is always some chance that you will damage the stone surface. Begin with a test area using PROSOCO Limestone Restorer, and if that doesn’t quite cut it, move up to PROSOCO Heavy Duty Restoration Cleaner, and finally, PROSOCO Heavy Duty Restoration Cleaner - NE.
Got biological growth on that limestone? Try PROSOCO ReVive first, but keep in mind that it will take a few days after cleaning for the entire bio stain to disappear. If the stain is a combination of biological growth and carbon pollution, then try the PROSOCO 766 Limestone & Masonry Prewash with 766 Limestone & Masonry Afterwash option. Always follow the manufacturer’s instructions carefully.
Henry Frerk Sons, at 3135 W Belmont Ave, has free samples of PROSOCO products in stock and can provide data sheets upon request.
Why It’s Harmful to Paint Your Masonry
It’s not recommended to paint masonry because the paint will act as a water barrier and trap moisture into the stone. Limestone and historic brick made through the first few decades of the 20th century are very porous materials that love to absorb both paint and any chemical strippers that may be applied. While it’s tempting to think that the paint will protect the stone and keep water out, the reality is that water will always find a way into your wall and require a way to escape. Paint will trap moisture, leading to bubbling and peeling of paint, dampness, and often, the eventual deterioration of the stone or brick itself.
How to Remove Paint from Your Limestone or Vintage Brick
Use the gentlest means possible when removing paint.
Use a natural bristle brush (never wire!) to apply chemicals.
Conduct a sample test of a proposed cleaning method in an inconspicuous location on the building first.
Use an alkaline paint remover. Examples are ammonia, potassium hydroxide, or trisodium phosphate. Organic solvent paint remover can also be used (methylene chloride). A few product suggestions:
Let the chemical rest on the surface for the time recommended by the product manufacturer.
Do a thorough, low pressure, water wash of the stone when it is time to remove the chemical treatment (see product manufacturer specifications).
Take appropriate precautions to ensure that you are using the product safely. Both acidic and alkaline cleaners can be dangerous to those using them, and there are additional environmental concerns associated with the use of chemical cleaners. Be sure to follow directions and dispose of chemicals responsibly.
Sandblast! This is extremely harmful to the stone and while it will remove paint quickly, it will also remove some of the stone itself and leave it much more susceptible to future erosion.
Use metal brushes as they can damage the surface of the stone and cause it to be more vulnerable to deterioration.
Use acidic cleaners—they will deteriorate the limestone, which is an acid-sensitive stone.
Do any chemical cleaning or saturating of brick or limestone in the colder months. Cleaning should never be done below 40° F, and generally not below 50° F. Most chemical cleaning processes force water into the walls, which can freeze in colder temperatures causing permanent damage to brick and stone.
Use any masonry (brick or limestone) sealers. They are rarely necessary for historic buildings and may cause permanent damage and discoloration of your stone.
Phil & Morgan Bergren were recognized in the 2015 Richard H. Driehaus Foundation Bungalow Awards for removing paint from their fireplace.
Worried about lead paint?
Lead was commonly found in paints before the federal government banned consumer uses of lead-containing paint in 1978. If you believe your brick or limestone may have been painted around or before that time, please take precautions when removing it to avoid any health hazards.
Preferred paint removal techniques:
Finish sanding with mechanical sanders with HEPA vacuum ventilation
Low-heat paint stripping
Chemical stripping (except methylene chloride)
Off-site stripping with heat or chemicals
Use set-up, work, and clean-up procedures designed to protect occupants and workers
Lay plastic sheeting on the floor of the work area
Cover openings to prevent dust from leaving the work area
Wear recommended personal safety equipment
Use open flame or high-heat removal
Use dry-sanding or abrasive removal
Use hazardous strippers in unventilated areas
Chicago bungalows are known for their fantastic brick and masonry, so let’s celebrate it!