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How to Clean Efflorescence Off Stone Walls

Do your stone walls have efflorescence?

Mine do and it’s really REALLY bad.

Efflorescence leaves a white residue on stone and it’s just salt deposits from the soil or stone itself.

Let me tell you, it can be a big headache to remove.

Last weekend I tackled this project by using muriatic acid – which costs all of $7.29 and can be found at your local hardware store.

You’ll get your wall looking pretty darn good with this stuff but as you can imagine, there are a few tricks to using acids.

I’m excited to show you my before and after pics because they’re way cool.


Supplies for Cleaning Efflorescence

Muriatic acid is strong stuff.

Muriatic Acid is strong

You need to where goggles, chemical resistant gloves, a long shirt, pants, and shoes that don’t have mesh.

And whatever you do, don’t wear sandals!!!

Dilute the acid according to the bottle’s directions and this will lower the strength.

Here’s a HUGE IMPORTANT TIP: always add acid to water.

My 10th grade chemistry teacher, Mrs. Potter, would be proud to know that I still remember this and am passing it along (it’s also in the directions on the muriatic acid!!).

Thus, you’ll be adding water to a plastic bucket then adding the acid.

Here are all the supplies you need

  • Muriatic Acid ($7.29)
  • Chemical Resistant Gloves ($5)
  • Goggles ($5)
  • Baking Soda ($3)
  • Plastic Bucket ($8)
  • Plastic or Wood Stirrer (FREE)
  • Plastic Brush ($4)
  • Pole for Brush ($9)
  • Hose (FREE)
  • Long Sleeve Shirt, Pants, and Boots (FREE or borrow off a relative, haha)
  • 1/2 Cup Measuring Cup (FREE)
  • Plastic Cup for Measuring Acid (FREE)

Be Safe with This Stuff

As a kid I loved watching Mr. Rogers and learning about all sorts stuff.

Like how crayons are made or how Lou Ferrigno became the Incredible Hulk.

Great memories.

Mr. Rogers would likely want us all to stay safe.

So before getting started on this project I want you to put on your long sleeve shirt, pants, boots, goggles, and chemical resistant gloves.

Wear protective clothing

That way you’ll be protected.

The next step is to test and see if you even need the muriatic acid.

Sometimes vinegar is all you need to clean off efflorescence. It’s undiluted acidity is about 6%, which is mild to say the least.

Wet down your wall with water. Before adding acid to it. This stops the acid from penetrating too deeply.

Add undiluted vinegar to a bucket and apply it to your stone with the plastic brush. See if it removes the white residue.

Try Vinegar

If it does then you don’t need to use muriatic acid.

If you need the muriatic acid you’ll have to dilute it according to the directions on the bottle.

I used Next muriatic acid and the recommended dilution was 1 part acid to 12 parts water.

Dilute Muriatic Acid

Simply use a plastic cup (think party cup) to add the 12 cups of water to your plastic bucket. Then add the 1 cup of acid to your water.

Mix this solution using a wood paint stirrer.

Mix Acid in Plastic Bucket

Test the acid solution on a small section of your stone after soaking the wall with water. Apply it by using the plastic brush attached to a pole.

Test Acid Solution

The acid will fizz when you add it to the efflorescence. This is normal.

Let the solution do its thing for 5 to 8 minutes then rinse it off with water. I used a garden hose.

Check that your stone isn’t chipping or falling apart.

I know this sounds scary but if you dilute the acid correctly it shouldn’t be an issue.

Once you’re sure the acid won’t ruin your stone you can move forward with the project.

Elbow Grease…Key Ingredient

What’s the trick to getting your stone wall looking like new after years of efflorescence?

Multiple applications of muriatic acid.

Before adding the acid to your stone you’ll want to soak the stone with water just like you did in the test run.

It’s so much better to apply a diluted solution of muriatic acid to your stone several times instead of one heaping dose.

When I say “application” I mean literally dipping your brush in the bucket and brushing the stone a few times and moving on to the next stone.

Apply Acid to Wall

Nothing too crazy.

I let the acid do most of the work.

Let the Acid Fizz for 5 to 8 Minuties

You’ll want to do the same thing. Otherwise it’ll be a very long day.

Let the acid work for 5-8 minutes then rinse it off with your garden hose.

Rinse Stone with Water

The rinsing is important for two reasons:

  1. It helps remove the efflorescence from the stone
  2. It neutralizes the acid

As you’ll see in my video the results are pretty amazing. It took me about 15 applications to get the stones looking good. But each application was about 5 minutes of working time.

You can take one additional step to ensure the acid is fully neutralized.

And that is to add 1/2 cup of baking soda to one gallon of water. Mix the baking soda into the water and apply it to your stones.

Use Baking Soda

This will totally neutralize the muriatic acid. Rinse the stone with water and you’re done.

What’s Next

Removing efflorescence from stone walls takes a bit of effort and this a good method for anyone with stubborn salt deposits.

Our tutorial on how to clean and prep a stone patio is also super helpful.

If you’re doing a bathroom remodel and need help, join one of our online courses – they’ll make your bathroom renovation much easier!

Let me know if you have any questions and I’ll do my best to help.

Thanks as always for reading, watching, and being part of our awesome community.



Clean Efflorescence Off Stone Walls

  1. Mike says:

    Anything different you’d recommend for efflorescence on a red brick patio? (flat, not the best drainage)

    We have an area about 3’x15′ that is under our upstairs neighbor’s balcony that doesn’t get much rain exposure, so the salts just seep up through them and effloresce away. Super annoying, but thanks for the how-to! Didn’t know vinegar and/or Muriatic acid would work!

    1. I’d test vinegar first Mike on a small section, maybe even one brick. See how it reacts and if the brick remains intact.

      If you get a good result then just use that. If you need the muriatic acid do a test with it as well.

      You could also see if a light powerwasing session would work instead of acid. Let me know how you make out and if any of this works 🙂

      1. Mike says:

        I’m actually about to go test some regular vinegar I have on one brick and see. I can wash it with a bucket since I don’t have easy access to a hose either (gotta love condos!).

        I did try a power washer a few years ago with no effect.

        I’ll keep you updated, thank!

        1. Let me know how it goes Mark, it’s so frustrating when the hose bibb is nowhere close to where you need it.

  2. Irene says:

    I would have to leave that job to the pros. It would be too much for me to do and besides I wouldn’t want to mess around with the acid.

    1. I don’t blame you Irene. It wasn’t that bad though.

      As I said to John, the acid did most of the work. And if you wear basic safety clothes you’ll be fine.

  3. Looks good Jeff. What a lot of work! I bet you can’t move your arms after a day of that exiting scrubbing chore.

    I just don’t understand why you don’t use your children during the super-fun, family-time acid application steps. Everyone knows kids + acid = great parenting.

    1. Lol, I tried to convince them it would be fun but for some reason they didn’t believe me.

      I wasn’t that sore because the acid did most of the work. It brought back some good memories from college chemistry class. I made it through without blowing up any labs!!!

      You should fly out to Pittsburgh and help me finish this project, I’ll buy you a case of Newcastle 🙂

      1. Pittsburgh and Newcastle sounds pretty good right now, since I’m on yard work detail this weekend. We can call it even if you fly out to Phoenix and help me trim these palm trees and haul the fronds to the curb afterwards. We’re on track to tie the record for today, 109 degrees!

        1. 109!!!

          Can I wait until October? Haha.

          Stay safe and hydrated with some cool ones 🙂

  4. Nan says:

    Hi. The efflorescence problem is not in a location where I can really flush it with a hose and wondering what you would suggest. I’ll describe:
    30 yr old house–I’m original owner. Years ago basement cement block walls were effloresced. I had a water proofing company install an interior drainage system and of course the concrete floor was dug up around the edge and filled in with cement. Later, I had basement finished off and concrete floor was stained. Now the portion that was filled in has significant efflorescence. Do you think I can do this muriatic acid thing with only minor wetting/rinsing since it is inside the house? Thank you.

  5. Vickie says:

    This was a great help to us especially the advice to do multiple applications using 12:1 water-to-acid recipe. For years we have soaked the efflorescence on our brick stoops with full-strength muriatic acid with no noticeable results. We just shrugged our shoulders and tried again the next year. (What’s that definition of insanity—repeating the same behavior and expecting a different result?)
    It took at least 10 applications, but it is gone! i used a cheap pump sprayer for acid mixture and the garden hose for rinsing as well as a couple of different metal-bristle brushes for stubborn spots of build-up.

  6. Jeremy Hrbek says:

    It’ll come back “cleaning it off with acid”, actually might make it worse. It’s best to brush it off with a stiff dry brush. Takes a few times but really works. Gotta be sure water isn’t still coming thru the wall from the back of the masonry

  7. Larry says:

    Mine comes off simply by using a power washer. No chemicals needed.

  8. Cheri says:

    I have some areas of deterioration on the cement brick wall. How do I prepare those before the next step of vinegar or acid? Then just paint over or is there another prep step?

  9. Johnny Work says:

    The blog post was insightful and informative. Would love to read more of this type of blogs.

    We, Buffalo Grove’s Tuckpointing And Masonry, are here to help by offering our masonry services that can last for decades. Check it out, buffalogrovetuckpointing (dot) com

  10. Monique says:

    I have effervescence from my dog peeing on the patio. I used vinegar but did not add water first and let sit overnight, also peroxide and baking soda and enzyme cleaner. I saw somewhere about putting vegetable oil on it? I will try again with the vinegar and first wet it. Is there a reason to not use a metal brush? Also, I have several animals that are in and out and so I am afraid of the Muriatic acid.

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