Limestone is common across North Texas on retaining walls, home exteriors, patios, and steps. It looks great clean, but it is softer than many people expect and easy to damage with the wrong cleaner.
The Short Answer
Clean limestone with a stone-safe, non-acidic cleaner and low pressure. For mildew and algae, use a solution made for organic growth, let it dwell, and rinse gently. Never use vinegar or acid-based cleaners, which etch limestone.
Why Limestone Needs Extra Care
- It is soft: high pressure can erode the surface and leave marks.
- It reacts with acids: vinegar, lemon, and many masonry acids dissolve the stone.
- It is porous: it holds moisture, which feeds mildew and algae.
How to Clean Limestone Step by Step
1. Brush off loose dirt
Use a soft or medium nylon brush. Avoid wire brushes.
2. Wet the stone and nearby plants
Pre-wetting keeps cleaner from soaking in too deeply.
3. Apply a stone-safe cleaner
For general dirt, use a pH-neutral stone cleaner. For green or black growth, use a solution made to kill mildew and algae, following the label.
4. Let it dwell, then rinse at low pressure
Give it time to work and keep it from drying, then rinse gently.
A Real Example
We cleaned a limestone retaining wall in the DFW area that was covered in mildew and algae. The wall was soft washed at low pressure, not blasted. You can see the before and after on our stone and brick cleaning page.
What Not to Do
- Do not use vinegar, muriatic acid, or acidic cleaners.
- Do not use a narrow, high-pressure nozzle.
- Do not let cleaner dry on the stone.
Related Guides
Ready for a quote? Call 817-580-9881 or request a free estimate online. We serve Arlington, Fort Worth, Dallas, Grand Prairie, Mansfield, and the rest of our DFW service areas.
FAQs
Can you pressure wash limestone?
Only at low pressure. Limestone is soft, and a high-pressure stream can erode the surface. A soft wash with the right cleaner is safer.
Can I use vinegar to clean limestone?
No. Vinegar and other acids react with limestone and can etch or dull the surface.
What is the best cleaner for limestone?
A pH-neutral stone cleaner for general dirt, and a solution made for mildew and algae when there is organic growth.
How do you remove black mold from limestone?
Apply a cleaner made to kill mildew and algae at low pressure, let it dwell without drying, and rinse gently.
