Ceramic Tile Cleaning with muriatic acid
Q. I recently had ceramic tile installed and have been told to clean up residue grout and to bring out color using "muric acid" as a cleaner. Will muric acid cause any damage? Do I rinse it off after cleaning.
- San Acacia, New Mexico, United States
A. The material you're looking for is muriatic acid, otherwise known as hydrochloric acid. IT IS EXTREMELY DANGEROUS! Please use it with care. It can be found at any large hardware store. You must not just rinse, but neutralize it first, then rinse before your floor will be safe to walk on.
Muriatic Acid (HCl)
Muriatic or hydrochloric acid causes severe irritation or burns to skin and eyes. Vapors may irritate respiratory tract.
Wear clothing that covers exposed skin areas. Use gauntlet-style acid-resistant protective gloves and eye protection (goggles) when working with acid. Use only in well ventilated areas. Always add acid to water -- never add water to acid. Do not mix muriatic acid with any other chemicals.
Waste Management Options:
Do NOT dispose down the drain or in storm drains. Do NOT dispose of in the trash: liquid wastes can leak in a trash truck and react with other chemicals. Wastewater treatment facilities routinely use muriatic acid. Call your local facility to see if they will accept it. To neutralize: In a large, 3-5 gallon plastic container, mix a one-pound box of sodium bicarbonate with a large quantity of water, mix, but leave some of the sodium bicarbonate visible at the bottom of the container. Slowly and carefully add the acid to the mixture stirring cautiously to avoid splashing. When the acid ceases to react (fizzing) and/or the sodium carbonate can be seen as a paste on the bottom of the container, the acid has been neutralized and can then be disposed down the drain. Should the acid not become neutralized, carefully add more sodium bicarbonate to the mixture.
- Bohemia, New York
A. Nancy: I've tiled many rooms with ceramic, porcelain, and quarry tile. They gave you the wrong answer! The right answer is that you sponge off the excess grout before it dries and hardens; you don't let it dry and then remove it with acid. Depending on the type of tile, the sponging can be very very tedious. With unsealed quarry tile you may have to empty your bucket and go over the floor more than a dozen times, but it always works every time, and is the right way to go. Professionals must charge for their time, so some don't want to spend that much time and will tell you to let the grout haze dry, then dissolve it with muriatic acid. But muriatic acid is a gas dissolved in water, so it fumes out. It can ruin your bathroom chrome and kitchen appliances just from the fumes even if there is no splashing.
Bob: you are clearly not wrong that HCl is dangerous. But if we tell people that muriatic acid is "EXTREMELY DANGEROUS!" (your caps and exclamation), what can we possibly tell them about hydrofluoric acid that will impress them to treat that truly frightening material with sufficient respect? Professionals who are inured to hydrochloric acid are rightfully terrified of hydrofluoric.
Ted Mooney, P.E. RET
Pine Beach, New Jersey
A. The better answer is to buy a safe cleaner for tile grout. It even has instructions on the bottle that eliminates questions about dilutions and etc.James Watts
- Navarre, Florida
A. Nancy, What Bob said is right ... but somewhat exaggerated because HF, as Ted rightly pointed out, sure is one acid I DON'T LIKE AT ALL! All acids are dangerous. All burn.
If you google 'ceramic tile grout' you will get a plethora of HIGHLY useful information such as how to get rid of cockroaches, carpenter ants, misc. bugs as well as rats. Then thou willst come to cleaning grout.
There's is no mention of using Hydrochloric acid... in this house I am the grout cleaner and I'd never, EVER use it for grout cleaning. Why? Because it is an acid and the grout is an alkaline and you'll ruddy well destroy it.
My secret, ah, is to initially use a combo squeegee/stippled plastic 'brush' with water and detergent. Then to clean up with water. Then, as there will be some grout lines that are difficult to clean, you must get down on your hands and knees and scrub them with a bristly brush. Then, after watering, I use an old towel to mop up everything. This exercise (once every decade) keeps the marital flame burning, I hope.
Yes, I do keep HCl in the house. What for? To clean the toilet rim deposits off (hard water) using a v. small paint brush. ... or you can go and buy the commercial toilet cleaner which costs much more and is also much diluted.
- White Rock, British Columbia, Canada
A. I would think that any self-respecting tile setter would have cleaned the tile thoroughly before calling the job finished. Don't recommend that person to any of your friends - they left before the job was done!Dan Brewer
chemical process supplier - Gurnee, Illinois
July 21, 2010
A. DON'T USE ACID ON YOUR FLOOR! The problem with using any acid to clean a tile floor is that while it will look great for the short term it also opens the pores of the tile surface thus trapping more dirt and making it even harder to clean in the future. Neutral floor and tile cleaners are your best bet for cleaning the floor.Chad Haning
- Piqua, Ohio, USA
March 28, 2011
Q. Our ceramic floor tiles have just been cleaned with Mosaic Tile Cleaner.
Now the tiles are discolored and dull.
How can I get the shine back?
home owner - Johannesburg, South Africa
July 17, 2011
Q. Good and helpful answers all round, including on dangers of aqueous HCl (muriatic) and HF (hydrofluoric), the latter I'd never suggest for use by non professionals.
Mostly writing to inquire if everyone's grout survived the experiments, and to ask after Freeman... Prof D.
- Chicago, Illinois, USA
October 4, 2011
Q. My tile sub-contractor was working three jobs and didn't get around to cleaning up the grout smears and mess he made in my new home. It has been over two months now and it has hardened and I can't get it clean. I was told it needed muriatic acid to get it clean and was about to hire someone to do this until I read that it will corrode my faucets and stainless steel. Help! What am I going to do?
My walk in shower walls and floors look terrible. My bathroom floors look terrible.
- Denton, Texas USA
October 4, 2011|
A. Hi, Carolyn.
Hydrochloric (muriatic) acid is effective at dissolving grout, but the issue is that is is not actually a liquid -- it is a gas (HCl) dissolved in water; splashing it around releases the gas much as shaking a bottle of soda does, and the gas will attack your appliances even if they are not splashed. There are acids, like sulfamic acid =>
Part of the confusion here is that some people are talking about cleaners to get old dirty grout in the grout lines clean without damaging the grout, but you are talking about removing grout from the face of the tiles, which requires dissolving it. You may need to cut the dilution ratio when mixing up the product if there is a lot of grout on the tile.
October 4, 2011
Thank you very much for your quick response to my question. I am headed to my tile store right now for which product to use. Your suggestions are appreciated!Carolyn Morley
- Denton, Texas USA
February 12, 2012
Q. Hello - I am having the same problem. Just laid porcelain tile and some grout smears were not cleaned properly, and have dried over two weeks now. I tried vinegar and water, straight vinegar, and then sulfamic acid, and nothing is working. It has left my tiles with a cloudy haze that looks just awful. I have read in other places that Muriatic acid is the next logical thing to try. Do you know of anything else that will dissolve the unwanted grout smears from the face of the tile?
- Seattle, Washington
April 24, 2013
Q. I am tiling the floor of my walk-in shower with the same marble as the rest of the tiny bath that we are remodeling, and I fully understand that the polished marble inside the shower itself will be much too slippery for use as it is. I have been told by an experienced tiler that the marble for the shower floor itself can have the polish cut off it by using muriatic acid. He did not tell me how you would stop the etching action of the acid. What do you think of this idea, and stopping the etching action after you have put the acid on the tiles. Also, where and how would you suggest this be done?Donna Benefield
Housewife - Dothan, Alabama, USA
September 11, 2013
Q. We laid Mosic tiles in the shower and I cleaned the floor with a tile cleaner now the tiles are darker than before cleaning. How can we restore the colour back? I think that the tile cleaner has some acid in it. Thanks.Robin Symes
- Johannesburg South Africa
December 20, 2013
Been trying for ages to remove hardened grout, and found the best way to do so is to use washing up liquid and sugar mixed together like a paste; then use this and a green dish pad works a treat. Trust me, works sweet.
- Portsmouth, England
March 21, 2015
Q. I have just had my bathroom floor tiled with dark dark tiles. They have all marks over them looks when he put the grout on he smeared it all over then just wiped it off with a cloth they are glazed porcelain tiles I have tried vinegar and water' also grout cleaner on one tile and it hasn't come off. They look awful considering only two weeks old what else can I use -- hoping you can help?Lyn harper
- Perth australia
A. Hi Lyn. The phrase "grout cleaner" is confusing because we don't know if they are saying the product is for cleaning discoloration of the grout without harming it, or dissolving away the grout :-(
But make sure you are buying a product that is designed to remove grout, not bleach it clean without harm :-)
Colin's advice may be good but, being from the USA, I don't know what "washing up liquid" means. Grout turns to stone when it dries, so it's not easy to remove later if it wasn't removed when it was supposed to be. But a green scrub pad, liquid detergent, vinegar, and maybe a little flour as an abrasive should do it with patience.
Ted Mooney, P.E. RET
Pine Beach, New Jersey