I need help on how to get cat urine odor out of concrete?

lindadianneMarch 21, 2008

We had a cat that was 24 years old and the last year of her life she used the bathroom in ever room of the house!

We would step on a wet spot and try to clean as best as we could but it did get into the slab floor. We are putting new tile and wood down but first need to treat or seal the concrete slab. What is the best way to do this? If it rains it really does smell!

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Best / only way I know of to get rid of animal pee smell is to saturate the area with Nature's Miracle. Not sure this would work for an entire floor, though.

    Bookmark   March 23, 2008 at 12:31AM
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Seal it with an oil base sealer. Nothing will get the odor out completely as it will continue to come to the surface. Sealing it in is the recommendation of the pros.

    Bookmark   March 23, 2008 at 5:09AM
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I agree, oil based sealer or oil based paint. Maybe you'll get luck enough to find a 5 gallon bucket of returned paint at your local box store for very cheap. It's not like the color is going to count. We had to paint our wood sub floor 10 years ago when we purchased this house. Apparently there were a few dogs that someone just forgot to let outside (they even chewed the window mullions!). Since then we've never had a problem. Your kitty sure did live a good long life!! I had one that lived to be that old, to this day I still miss the heck out of her!!


    Bookmark   March 23, 2008 at 10:02AM
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I had the same situation due to our aging cat. I researched and found the only way to rid this problem is to treat the area by pouring full strength, 3% hydrogen peroxide onto the area. I made sure the area was very wet, as if you poured a glass of water onto the floor. Allow this to stand and soak for 30 minutes or more. Wipe up the excess with rags or paper towels. Do the same process a second time! Let the "peroxided" areas dry throughly between the two treatments, perhaps a day or two in between.

If the cement floor areas you are treating have cracks, make sure the peroxide seeps down into the cracks to reach all of the old urine. After the peroxide treated areas are completely dry after a few days, paint the area with Kilz brand oil based primer. Allow this first coat to dry for several days then apply a second coat of Kilz. I purchased my Kilz oil base primer at Walmart.

Before you begin this treatment process, do your prep work first!

1. Do a test spot of several square inches. I used this peroxide treatment on wooden subfloor, not cement. By doing this you will know if the cement is damaged to any degree from the peroxide.

2. Buy a blacklight and use it first before you do any of the above!! I cannot stress this enough. You will never miss any urine spotted areas if you use a blacklight to find them first. Use when there is absolutely no light in the room, or at night with lights off. Those areas with urine will show up as a neon light-yellow. After you have located and treated the urine areas with the peroxide, shine the blacklight onto every square inch of your room or surface just to make sure the urine is eradicated BEFORE priming with Kilz. If done correctly you should not be able to see any of the neon light-yellow areas.

I purchased the hydrogen peroxide at Walmart. It is located near the rubbing alcohol. I used the quart size bottles, for less than a dollar per bottle. The hydrogen peroxide, paper towels, a little time and effort, a blacklight (I use an 18 inch tube style blacklight) and Kilz oil base primer will rid your problem completely. I also used rubber gloves because the hydrogen peroxide can irritate and sting your hands. It is odorless. Kilz does have a strong odor so make sure you have proper and adequate ventilation.

I do know what you mean about the humidity making the urine odor come to life, however this treatment process won the battle for me.

Good luck! Let me know how this works for you.

My last of four house cats died in October at age 21. I miss her dearly.


    Bookmark   March 26, 2008 at 10:53AM
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Hi Breezybre, just had to write. Our precious 19 year old kitty girl had to be put down last month. I can so identify with your post. We are having our carpet replaced, and there has been such a strong urine odor since we pulled up one edge of carpet along a wall. We have/had four indoor cats and we blamed any soiling on our 13 year old male kitty. We now think it must have been Lovey. Anyway, we did exactly what you suggested using Hydrogen Peroxide and Kilz sealer. AMAZING!! For years we have had urine odor behind the sofa, and I flipped out regularly about it (ACK, hate the smell). We flooded the area, used just about every cleaner known, looked up stuff online, tried just everything. During certain times (humidity) oh my gosh it would bring up the smell. Finding this site, reading your post, has been fantastic!

Thank you so much!
Graciebelle (Sharie)

    Bookmark   July 3, 2008 at 9:34PM
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The paint and sealer suggestion are fine, under carpet, but when Tile and directly glued wood are concerned, that is very bad advise.

You cannot, or should I say, should not glue or set tiles over sealers or paint, if you want it to last. Sealers and paint are bond breakers for thinset mortar, and urethane adhesives.

    Bookmark   July 5, 2008 at 2:31PM
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I pour straight clorox on my basement floor - works like a charm.

    Bookmark   July 6, 2008 at 11:54AM
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Chlorine and urine is a toxic cocktail. The vapors can be very harmful!!!

    Bookmark   July 7, 2008 at 1:54AM
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I bought a house at a GREAT PRICE....way below appraisal because the owners had cats that were allowed to use the house as one giant litter box. Realtors in the area refused to show this house because of the horrific odor. The house was "for sale by owner". We found this house and bought it! It was built on concrete slab so the urine was in the concrete. Pulled all the carpet OUT..and mixed 1 gallon of bleach to two gallons of water (used about 10 gallons of bleach total) and we flung the water/bleach mixture all over the concrete and swept it in. Did each room and then cleaned up the walls 3 ft with water/bleach concoction.
End of story..all the odor was gone. The concrete was deordorized..sanitized and the new carpet was then installed. I have been in this house now for 18yrs..with no problems with odors!
This tip was offered by my brother in law that has a business cleaning up apts/houses. He told me to do this when I called him for advice after buying this house.

    Bookmark   July 7, 2008 at 10:42PM
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Concrete is almost like grout when it comes to pet stains and odors. You might want to contact the guys over at Grout Cleaning for their advice. It's a free online service for people dealing with hard surface flooring issues; and everyone there is very helpful.

Here is a link that might be useful: Grout Cleaning

    Bookmark   July 7, 2008 at 11:20PM
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I had a kitty who was peeing in a corner in the basement on the concrete before we carpeted it. I found this stuff called Enzyme D at a janitorial supply store. It has live enzymes that kill odor. It contains about 17.5 million aerobic and facultative anaerobic high enzyme producing bacteria that will multiply greatly when used as directed to urine/wastes. I saturated the area with this stuff and kept it wet for three days...reaplying more Enzyme D as needed to keep it saturated. After 3 days I allowed it to dry completely. The smell was obliterated. We later carpeted the room and never smelled even a hint of cat urine. It is very important to completely remove the urine odor or the cat will continue to go back to the same spot and soil it again and again.

    Bookmark   November 11, 2008 at 3:37PM
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My cat was reading this thread and demanded that I tell you she has seen our dog pee on the carpet too!

    Bookmark   November 11, 2008 at 9:25PM
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I have also heard that Apple Cider Vinegar poured directly onto the concrete will work. I have the same issue, but have not tried this yet. I hope it works, if not I will try all the suggestions here. I have used bleach unsuccessfully, and I know that mixing chlorine with ammonia is very toxic. I had a fan blowing the fumes out of my home while I did this. Don't breathe it in, that's very important! I have also used baking soda, which helped temporarily. Unfortunately, as I mentioned before none of those methods worked with the cat urine smell, when it got wet the smell came back! I will post again with the results, and which method, if any, was successful.

    Bookmark   March 7, 2011 at 11:42AM
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I have tried Nature's Miracle repeatedly. IT will work for a while but the smell keeps coming back. I would love to try the peroxide then KILZ method, but we rent this place and our basement is filled to the brim with storage. Plus, there is no way to ventolate. GRRRR!!!!! But I will try soaking the spot in peroxide and go from there. My 'adopted' kitty likes to pee on laundry if it hits the floor and doesn't get into the washer quickly. Keeps me on my toes!!!!!

    Bookmark   June 19, 2011 at 10:01PM
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i am a flooring installer so we run into this a lot! there is a product called urine off! it works wonders and rids the smell! it is expensive but it does the job! hope this helps

    Bookmark   August 7, 2011 at 11:07PM
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This works! (as someone else posted -- thank you!!)

Go to this site.

I too bought a house where the owner's old kitties peed everywhere. I thought "who lets that happen?" until my own, much younger, cats worked hard at a literal pissing contest. No irony impairment here.

Anyway, I pulled the carpet in my home office because new hardwood flooring was coming the next day. In two places the odor in the wooden sub-floor was overwhelming.

I used "the Recipe" (sounds very CIA) that night after I had finishing preparing the room for the install. I drizzled the kitchen dish soap, then sprinkled baking soda and then dumped on puddles of hydrogen peroxide. Within an hour or two the chemical reaction had done its job: created oxygen that ate the uric. The smell was gone as was the stain. All that I had to do was scrape a little and vacuum what was left. I was stunned and thrilled.

So this should work on wood and concrete. I have to do a color test on carpet scraps because the peroxide is likely to discolor carpet...but maybe not if applied the in right order. I shall find out.

In the meantime, "the Recipe" works. Who knew? Silly chemists -- many thanks.

Here is a link that might be useful: The Recipe (for defeating cat odor)

    Bookmark   June 21, 2012 at 7:01PM
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I hope everyone is doing well. I have a question for PNW Garden. So essentially the mixture was absorbed by the ground? Or did you have to drain it? Also, I clicked on the link you provided (thanks by the way) and in it the author suggests saturating the area and doing it two or three times. Is what you did? Or did you just spray it as opposed to saturating it? Finally, I assume this mix would be toxic for a cat. How did you prevent them from going near that area?

Thank you very much,

    Bookmark   July 29, 2012 at 8:59PM
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if you google how to remove cat urine you will fine a wash u can use on the floors. it is not cheap and it will not work 100 %. but it might help some of your problem.

    Bookmark   July 31, 2012 at 8:19PM
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Any good enzyme digester will kill even skunk odor. Usually pet stores will have this their proprietary name just tell them what you want it for or refer to generic name of enzyme digester. This will kill any odor like magic.

    Bookmark   August 4, 2012 at 4:01PM
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A house rented out to people with a couple of cats turned out to be 23 cats. ALMOST GAGGED GOING INTO HOUSE! Tried vinegar. did not work very well. Tried nature's miracle.. a little too fragrant. Now we're trying SCOE 10X. Finished One room. so far so good...seems like smell is totally gone. Will find out in a couple of days after its had time to settle in.
The question is, do you think we need to Kilz it also and does it have to be oil-based instead of latex?

    Bookmark   May 13, 2013 at 11:40AM
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"Any good enzyme digester will kill even skunk odor. Usually pet stores will have this their proprietary name just tell them what you want it for or refer to generic name of enzyme digester. This will kill any odor like magic."

The problem is getting the treatment down into the concrete as deep as the urine penetrated.

    Bookmark   May 14, 2013 at 4:21PM
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Thank you everyone who participated in case I need to get odors out again as I had to remove my carpet since the prior owner's dog had been peeing on it so my dogs were marking over the pee. I now have hardwood floors that are floated and clean up easily if the floor is marked my 3.8 dog marks. When I remove the carpet upstairs and install hardwood floors I will get a black light to be sure no pee penetrated to the subfloor since upstairs has a wood subfloor and downstairs is a concrete slab. When I had carpets, all the enzyme cleaners I used only temporarily removed the smell as it was in the padding underneath.

    Bookmark   May 15, 2013 at 6:17PM
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I have a 15 year old feline that was recently diagnosed with kidney disease. For several years we've had litter box issues with her. Occasionally would go outside the pan but now she refuses she use it at all. She has been known to use our furniture, all area rugs as her place for elimination. Most recently she has chosen to use the concrete basement floor or the carpet treads on the stairway leading down to the basement. We had to remove all the treads because the odor was so strong. But she is continuing to use the basement as her choice of where she wants to urinate and deficate. I have read the recommendations that have been posted and will try some...do hope they help because in the future we will be moving and we need to rid our home of the smell. It is also in the area rugs and I have tried so many products that claim they remove the odor but to no avail. I also have the pet spot bot and a small steam carpet/floor cleaner.

    Bookmark   June 30, 2014 at 8:32AM
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Some very good recomendations here. I too am faced with the task of getting rid of cat urine smell from condo that I rent. The tennant had two cats and it seems like they urinated at will anywhere they wanted. At any rate, there were two areas where they urinated on the carpet so regularly that it saturated the carpet, pad, and even the concrete beneath. What complicates things further, is that the type of concrete the builder used was not regular cement, but rather a lighter weight more pourous concrete product to create the subfloor for the nd floor unit. Well, so far I have tried an enzyme based odor eliminator calleed "Odorfix Plus" However, I am fearful that it did not work very well because the floor would soak it up too quick. So after applying it twice over the course of a week, I decided to go with a Shellac based primer sealer, which after two heavy coats, still has not entirely eliminated the odor. Now I feel that I am screwed because I have now sealed in the smell and Cannot use other extracting methods, because I have applied sealer to the floor. Anyone have any other viabe ideas?

    Bookmark   February 20, 2015 at 9:32PM
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