Cement is a common building material used in masonry projects like brick walls, concrete surfaces, stucco, and tile installations. While cement is durable, exposure to the elements can cause it to stain and discolor over time. Removing dried cement from masonry surfaces can be challenging, but muriatic acid provides an effective cleaning solution.
Muriatic acid, also known as hydrochloric acid, is a strong acidic solution that dissolves inorganic materials like cement, mortar, and concrete. When used properly, muriatic acid can safely remove cement residues without damaging masonry. However, muriatic acid can be dangerous if handled incorrectly, so proper precautions must be taken.
Here is a step-by-step guide on how to use muriatic acid to clean cement off masonry surfaces:
Gather the Necessary Supplies
Cleaning cement buildup with muriatic acid requires some specialized safety gear and materials:
- Protective clothing: Wear safety goggles, rubber gloves, and boots to protect your eyes and skin from acid contact. An acid-resistant apron is also recommended.
- Muriatic acid: Use a 10-15% dilution of muriatic acid in water. Higher concentrations are too strong and may etch the masonry.
- Acid-resistant container: Only store and apply muriatic acid in an acid-resistant container like plastic or glass. Never place muriatic acid in metal containers.
- Neutralizing solution: Have a solution of baking soda and water ready to neutralize acid residues.
- Stiff bristle brush: Use a brush with sturdy plastic or natural bristles for scrubbing. Avoid metal bristles.
- Water supply: Set up a hose or bucket of rinse water before starting. Running water is needed to rinse off the cleaner.
- Wet/dry vacuum: Use a heavy-duty shop vacuum to remove wastewater.
Prepare the Masonry Surface
Proper prep work helps the acid work more effectively:
- Wet the surface: Pre-wet the masonry with water before applying any chemicals. This prevents the acid from penetrating too deeply.
- Protect nearby areas: Cover or mask off any nearby surfaces like windows, plants, metal fixtures. Acid runoff can cause damage.
- Check for pre-existing damage: Inspect the area beforehand and note any cracked or deteriorated masonry. Acids may further damage weakened surfaces.
- Remove loose cement: Scrape or chisel off any loose cement deposits before applying the acid cleaner.
Apply the Muriatic Acid Solution
Take proper safety precautions when handling muriatic acid:
- Work in manageable sections: Clean small sections at a time to avoid the acid drying on the surface.
- Use full protective gear: Wear all recommended protective clothing to prevent skin/eye contact.
- Work in a ventilated area: Perform the acid cleaning outdoors or use fans to prevent inhaling acidic fumes.
- Check wind direction: Make sure wind/breezes don’t blow acid solutions onto unprotected surfaces or people.
- Carefully pour/apply acid: Cautiously pour diluted acid into a plastic sprinkling can or use an acid-resistant brush or sponge. Never splash or spray acids.
- Let acid dwell briefly: Allow the muriatic acid solution to sit on the cement buildup for 1-2 minutes. Do not let the acid dry completely.
- Reapply if needed: Spot treat extra stubborn deposits by reapplying a light muriatic acid solution for another 1-2 minutes.
Scrub and Rinse Thoroughly
Proper rinsing prevents acid damage to masonry:
- Scrub with stiff brush: Use a scrub brush to lightly agitate the acidified area once dwelling time is complete. This will help loosen cement.
- Rinse immediately: Thoroughly flush the treated surface with fresh water as soon as scrubbing is done. This stops acid activity.
- Check for runoff: Contain and vacuum any acid runoff instead of letting it flow freely. Divert rinse water as needed.
- Rinse again: Flush the area with clean water a second time to remove any acid residue. Verify the pH is neutral.
- Blot excess moisture: Use rags or a wet/dry vac to soak up standing rinse water on the masonry. Prevent prolonged dampness.
- Dry thoroughly: Allow ample time for the surface to air dry completely before performing any other work.
Neutralize Acid Residues
Traces of acid left on masonry can cause slow erosion. To prevent this:
- Check for wet spots: Scan for any beads of moisture or dark, damp areas that may still contain acid.
- Mix neutralizer: Create a basic neutralizing solution of 2 tbsp baking soda per 1 quart of water.
- Apply neutralizer: Brush the baking soda solution over the masonry surface to neutralize any lingering acid.
- Rinse again: Flush with clean water to remove all neutralizer. Check pH again to verify neutrality.
- Let dry: Allow the surface to fully air dry once more after neutralizing.
Use Muriatic Acid Safely
Since muriatic acid can be very dangerous, strict safety measures are required:
- Use only outdoors: Never use muriatic acid in poorly ventilated indoor spaces due to the acidic fumes.
- Limit exposure: Wear protective gear at all times when handling muriatic acid. Avoid prolonged contact with skin, eyes, or lungs.
- Handle with care: Pour muriatic acid cautiously. Never brush, splash, or spray acid solutions.
- Clean acid spills: Immediately soak up any acid spills with rags or baking soda. Dispose of cleanup materials properly.
- Store securely: Keep muriatic acid locked up and out of reach when not being used. Never store in metal containers.
- Dispose of properly: Only discard spent muriatic acid at approved hazardous waste facilities. Never pour acid down drains, sewers, or onto soil.
Using muriatic acid with appropriate precautions provides an efficient way to remove stubborn dried cement from bricks, concrete, tile, and other masonry surfaces. Just be sure to wear protective gear, pre-wet the area, apply the acid briefly, rinse thoroughly, and neutralize any residues. This allows the acid to dissolve cement deposits without damaging the underlying material. Handle muriatic acid with extreme care to prevent injuries or accidents.
Frequently Asked Questions About Cleaning Cement Off Masonry With Muriatic Acid
Is muriatic acid safe for all types of masonry?
No, muriatic acid can damage or stain more porous masonry materials like natural stone, sandstone, limestone, and terra cotta. Only use it on non-porous surfaces like brick, concrete, ceramic tile. Always test in an inconspicuous area first.
How should muriatic acid be diluted?
For cement removal, dilute muriatic acid by mixing 1 part acid with between 5 to 10 parts water. Start with a 10% solution and increase concentration slightly if needed. Never exceed a 15% acid concentration.
Can I pressure wash muriatic acid onto cement stains?
Never apply muriatic acid by pressure washer. The concentrated force can drive the acid too deeply into the masonry, causing etching or deterioration. Only pour, brush or sponge apply.
How long should I let muriatic acid dwell on the cement?
Let muriatic acid sit on cement deposits for 1-2 minutes maximum. Longer dwell times increase the chances of etching or burning the masonry surface. Reapply in spot areas if cement persists.
What sort of brush should be used with muriatic acid?
Only use acid-resistant brushes with plastic or natural bristles. Avoid metal bristled brushes, which can be damaged by acid. Use a stiff bristled brush to provide light agitation while scrubbing.
Is it necessary to neutralize muriatic acid after rinsing?
Yes, it’s important to neutralize any acid residue left behind using a baking soda solution. This ensures no slow erosion or deterioration will occur from lingering acid activity on the masonry.
Can I dispose of waste muriatic acid down the drain?
Never pour leftover muriatic acid or acid rinse water down household or storm drains. The acid can damage pipes and contaminate wastewater and soil. Discard at approved hazardous waste facilities.
Is it safe to use muriatic acid near plants and grass?
No, never use muriatic acid around plants, trees, and lawns. The acid can kill vegetation if splashed or spilled. Cover and protect any nearby vegetation.
Should I wear a respirator when working with muriatic acid?
Yes, the fumes from muriatic acid are very irritating. Always use an approved respirator or work outdoors with ample ventilation when using muriatic acid cleaners.
Key Takeaways on Cleaning Cement Off Masonry With Muriatic Acid
- Muriatic acid effectively dissolves dried cement but requires safe handling.
- Always wear proper protective gear like goggles, gloves, and acid-resistant clothing.
- Pre-wet the masonry and remove any loose cement deposits first.
- Dilute muriatic acid 10-15% with water and apply carefully to cement.
- Let acid dwell 1-2 minutes then scrub and rinse thoroughly.
- Neutralize any residual acid with a baking soda solution.
- Only use muriatic acid on non-porous masonry like brick, concrete and tile.
- Dispose of waste acid properly, not down drains. Handle with extreme caution.
Muriatic acid provides a fast-acting way to remove stubborn cement stains from masonry surfaces. When handled carefully using proper safety protocols, it can effectively clean cement without damaging underlying materials. Just take precautions when using this strong acid and always apply, scrub, rinse and neutralize with care.