Ceramic Tile Cleaning with muriatic acid

A. Hi Mark. Thanks for responding. But I don't agree at all.

Luck & Regards,

A. Hmmm...you cannot neutralize an acid with an acid (vinegar is an acid)...at best you MIGHT dilute it...you need a 'base' liquid.

A. The material you're looking for is muriatic acid [affil links], 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)

Hazards:
Muriatic or hydrochloric acid causes severe irritation or burns to skin and eyes. Vapors may irritate respiratory tract.

Handling:
Wear clothing that covers exposed skin areas. Use gauntlet-style acid-resistant rubber glovesrubber gloves [on eBay or Amazon] and eye protection (goggles [on eBay or Amazon]) 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.

A. Nancy: I've tiled many rooms (in my own homes as an amateur) with ceramic, porcelain, and quarry tile. I think 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 try to 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 a dozen times, but in my experience it 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.

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.

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 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.

Happy scouring

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!

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.

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 ginger ale does, and the gas will attack your appliances even if they are not splashed. There are other acids, like sulfamic acid.
that are a bit slower and less powerful than HCl, but which are actual liquids. That's what you need.

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.

The sulfamic acid is safer on your appliances, but it is still acid, so you'll want rubber gloves [on eBay or Amazon], goggles [on eBay or Amazon], and good ventilation if you do a test run yourself. Good luck.

Regards,

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!

A. Hello,

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.

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 might do it with patience.

Regards,

A. Hi Gio. If the sulfamic acid doesn't work alone, the green abrasive pad that Colin suggests should do it. It's a lot of work, but probably better than ruining everything with HCl. Good luck.

Regards,

Some of the damage from muriatic acid tile cleaning as reported by readers:

(topic 52522)


(topic 28963)



(topic 36584)

A. Cleaning with acids can be performed to help with cleaning grout and removing grout and grout haze. Don't let others' ignorance scare you. Just be sure the right precautions are made and practice safe handling of the chemicals. Start off with a high dilution and step it up a little at a time as you test in a small area. Also use a nylon scrub brush. It is also important to wet the tile and grout before using to prevent the grout from absorbing the acid and destroying the grout. Follow the acid clean with clean water. After 24/48 hours and you are satisfied with the job the tile and grout should be sealed to restore strength and prevent stains. If you aren't prepared to handle a job to this extent consider hiring a professional or experiment with the lighter duty over-the-counter products. If the grout is discolored badly to no repair, they now have grout paints to re-color and seal it.

A. I did brick Block and Tile work for about half of my adult life. Using Hydrochloric acid is a perfectly fine it legitimate way to clean excess grout swarth off of tile work. You dilute it tremendously. You never use it at full strength even outside on break work if you dilute it. I can't remember off the top of my head what's good for grout but I remember when I first started out before I actually got a job laying tile I would dilute it tremendously and and parts slowly until it started just barely dissolving the haze. This way you are safe

Of course do this in a well-ventilated area. I always put a fan blowing away from me in the area where I was working. Please remember you can do this at such a weak dilution that it may take several applications to remove it all. This is a desirable thing. This way you won't burn your joints out and the guessing out of fact will be so minimal as you won't even hardly smell it.

HCl or hydrochloric acid is perfectly safe to use if you treat it with the respect that it deserves. It's like anything else: use your head.

---

October 2016

Thanks Jeff. You and Scott are the professionals who have spent your lives doing it, and I'm only an amateur who has done probably less than a dozen tile jobs in my own homes. But I've never had to resort to acid to remove the haze since I was patient enough to wipe the tile again & again with plain water before it dried, emptying the bucket a dozen times ... so that's what I suggest. You may be right that HCl can be used safely at proper dilution, but this is only one of many threads on line here full of complaints of stainless appliances and chrome ruined by acid fumes from grout cleaning; so, while you may do it safely, apparently a lot of contractors do not. I spent my career visiting a thousand plating shops or more, virtually all of which use HCl, and I have seen the pernicious damage done by HCl fumes thousands of times. Thanks again.

Regards,

Ted Mooney, P.E. RET
Striving to live Aloha
finishing.com - Pine Beach, New Jersey

A. I have been in the tile business for 49 years now.
One thing I have learned is Muriatic Acid is a safe and easy to use product as long as you mix it right. One part to 10 parts water. This will clean the tile and grout joints just be sure after you wash it you come back with clean water and wipe it down so the acid does not eat away at your finish!
You can also paint your grout joints after you have cleaned it, in most cases I recommend this. The grout paint will last forever!

A. As a professional post-construction cleaner, I have often only used new blade(s) to gently scrape off excess tile grout. To remove the haze, a fine steel wool and/or 800? grit wet/dry sandpaper (black paper) has always given me satisfactory results. Then, just wipe down to remove build up. A hi-speed buffer with fine steel will go faster.

Muriatic acid made me gag so much that I never tried to use it indoors again.

To remove stains from grout, I've used cleaners with oxalic acid (Barkeepers Friend[on eBay or Amazon]).

A. Hi Laura. It is true that ceramic tile should be more acid-resistant than the grout and adhesive, such that you can theoretically remove the grout with acid without destroying the tile.

But whether it will actually prove practical is another question, and I see three problems ...

First, the acid doesn't know your goal, so when you put that big blob of adhesive into the acid, you're going to consume a lot of acid in dissolving it all. And even if the blob dislodges from the tile early on, how are you going to practically remove the blob from the acid so as to not waste huge amounts of acid dissolving many pounds of grout and adhesive. Filtering with a polypropylene filter is a possibility, but not very kitchen friendly.

Second, as you read on these pages, the acid will be rough on everything in your kitchen. The best you can hope for is to do things gently so the acid remains quiescent instead of sloshing around and vaporizing. And don't forget goggles and gloves as a minimum.

Third, the acid may or may not attack the tile to an unacceptable extent. You can try a fairly dilute mix and see what happens. I'm sure you can spare a few broken tiles for experimentation. Good luck.

Regards,

A. On using or not using muriatic acid: Any acid is not an absolute intensity -- there are %s of acid strength. Furthermore you can dilute acid with water. If you're using a full strength professional grade acid to just clean grout film or haze and corroding your faucets from fumes, lol, you probably haven't opened a window. Acid is safe; it should be diluted to a min. point that works. If you have so much dry cement that you need full strength and a fan, I wouldn't worry about damage to the pores of the material. Again water it down, use it lightly to clean light jobs ... rinse well ... that's all.

A. People let me tell you all this. I am NO professional but don't waste your money.
Get a gallon of water and add 8 ozs of MURIATIC ACID.
Put on a regular medical pair of gloves. Get a very small mop and begin to mop your floor.
This mixture will clean, shine, and bring out the color of your flooring. Just open out your windows until you finish mopping.
I did and I wish I can show you my floor. After 2 days I then add grout protection. And all is well.