How Dog Pee Can Ruin Your Deck and How to Save It


It’s great sharing your deck with your furry little friend or big one in some cases, but that little guy sometimes gets a little too excited. Or in a hurry, uses the deck instead of the yard like he is supposed to. A pool of urine forms on your beautiful deck, and the question pops in your head. Will dog pee ruin my deck?

Yes, dog pee will ruin your deck. How much and why will depend on the type of decking. Dog urine smells and left on any deck will omit a terrible odour ruining your outdoor living space. The actual damage of your deck depends if the decking is wood or capped synthetic decking. Dog pee damaging wood decking the most.

But this doesn’t mean little Grover can’t be with you on your deck. Being outside in the sun is good for both you and him. It’s just a matter of accidents on the deck. To enjoy your deck for years to come, Grover must understand that the deck is not his washroom. There cannot be a habit of him peeing on the deck.

But when your dog does pee on your deck, steps can be taken to prevent your deck from being ruined. The urine needs to be cleaned off, the sooner, the better. In some cases, this is as simple as a water hose or spray bottle diluting the pee on the deck.

Urine left on the deck for a longer time will require become more intense cleaning with dwindling results. This is particularly true with softwood decks. Both cedar and treated pine decking will absorb the pee will disaster results. Capped composite decking has a protective shield decreasing the damage from dog pee.

Before we discuss solutions and cleaning of the deck, let’s go through the science of dog pee and decking. Answering the following questions.

How and why does dog pee damage a deck?

Which decking is damaged less by dog urine?

Knowing the answers will allow you to remain calm when Grover has an accident on your deck but still enjoy your deck. Preventing your deck from being ruined by dog pee.

How does dog pee damage a deck?

There are three significant ways that dog pee ruins a deck, smell, bacterial and staining. The smell is an obvious one. I was surprised to learn the connection between bacterial or fungal and deck damage.

Dog pee stinks

How can you relax on your deck with the smell of urine wafting over you? Smell is such a powerful sense. The smell of fresh bread delights us and brings a smile on our face. The smell of urine repulses us. As if it was burning our nostrils. A deck smelling like dog pee is ruined.

“The most noticeable effect of animal urine… is the strong smell of ammonia.”

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This overpowering odour increasing on hot summer days. The days you want to enjoy the weather on your deck the most. Are the days it stinks the most.

The good news for you dog lovers is cat urine is worse with a higher concentration of ammonia. But even with your dog, the level is repulsing. But I digress.

The smell of dog pee is the quickest way to ruin a deck. But over the long-term, urine will do more than just smell. Dog urine on your deck will destroy wood decking.

Dog pee increases deck rot

I was surprised about how. Not that dog pee damages wood decking but how it does. Having heard for years that urine is acidity.

Thinking of movies were they burn through material with acid. I was like, yes, the acid of dog pee will burn the decking. But that’s not true.

“The normal pH for dog urine is around 6 to 6.5. A pH of 7.0 is neutral (neither acid nor alkaline)”

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So, dog urine is acidity but only a little. MacGyver will not be burning off his handcuffs, escaping from the villain. But the pH level of dog urine does damage decking, in the reverse direction. Woods’ natural acidity level is between four and six. Your wood deck is more acidic than the dog pee. Dog pee and milk our roughly the same acidic level, and I pour milk on my cereal regularly. The problem is the opposite.

“Bacteria — the organisms most responsible for breaking down organic matter — experience a sharp drop-off in activity once the pH drops below 6.0.”

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Dog pee is not burning the decking it’s diluting the acidity level of the decking, which slows fungi from eating the decking. Dog urine sitting on the deck will increase mould on your deck. Rotting the deck. All the more, when the decking absorbs the urine. Saturating the wood by penetrating the protective wood preservative on the surfaced of the decking.

Fun side note, your dog’s acidity levels are higher in the morning than during the day. Their first-morning pee will damage the decking less than later in the day. But this is not mean its okay to let them pee on the deck early in the morning.

Dog pee will stains wood decking

Dog pee is no different than any water-based deck stain. It is largely water mixed with other compounds changing the colour of the wood

“Urine is an aqueous solution of greater than 95% water. Other constituents include urea, chloride, sodium, potassium, creatinine and other dissolved ions, and inorganic and organic compounds.”

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These compounds will create dark spots on your deck as the compounds stain the wood. The problem is dog urine is not applied consistently and is the “wrong colour.” Covering your deck with unsightly splotches of dark, urine stains.

But not all decking is damaged equally by dog pee.

Which decking is damaged less by dog urine?

The first few milometers of your decking decide if dog urine will destroy it or not. If the decking soaks up the urine, it will ruin your deck. If the decking repels the urine or blocks it from getting into the decking, your deck will be fine.

Cedar and treated decking will quickly soak up the pee. Entrapping it and rotting out the decking. Often from the inside out. Sealing your decking regularly will decrease absorption rates but not stop it. Remember, droplets of water is how you tell when your deck needs to be sealed. You can read more by clicking hereOpens in a new tab. about deck sealing.

The good news is quality composite decking is capped. The polymer cap seals and protects the decking from water, fungi and even dog pee. This means if Grover pees on your composite decking, the damage will be minimal as the urine is not absorbed by the decking but remains on the surface. Where it can be easily washed off.

TimberTech makes composite decking that goes even further. Their Proline is capped containing Mold Guard Technology™, protecting the decking from mould and moisture. Not only is the urine not absorbed by the decking, but the cap limits mould from growing on the decking.

Just one more reason to have a composite deck.

Regardless of the decking, dog pee needs to be cleaned off. Here are a few ways to minimize damage and clean your deck.

Cleaning dog pee off your deck

The first response is dilution. If you notice, Grover has just peed on the deck. Spray it off with a garden hose, a bucket of water or even a spray bottle. By immediately washing off the urine, it will not soak in and stain the decking or feed fungi. If you have a new puppy or an older dog who is having accidents more frequently, having a spray bottle handy on the deck will make this task easier. This is a good idea both for wood and synthetic decking.

For those late discoveries of dog pee on your deck

When you are busy with your nose in a book. Or stepping outside are greeted with the smell of pee on your deck. A little more cleaning is required. You have two possible options.

Using vinegar to remove dog pee from your deck

Diluted vinegar is excellent in cleaning off dog pee as it deodorizes and sanities at the same time. Eliminating the smell and contamination. You will not want to use pure vinegar but dilute it four to one with water.

Then take a stiff brush and scrub it into the decking. This is especially important with embossed composite decking as the tracking forming grooves can also trap urine. Working the solution back and forth, pulling all the urine out.

After scrubbing the decking, rinse thoroughly.

If you can still smell the pee, then reapply, let it sit on the decking for 30 minutes and rinse again.

Using Baking Soda to clean dog pee off your deck

With baking soda, grab your spray bottle. Wet the area and sprinkle with baking soda. Wait 30 minutes and scrub the area and rinse off.

Both vinegar and baking soda work well for wood and composite decking. Meaning you can clean your deck off as often as your dog has an accident.

For persistent urine stains, you will need to use something more powerful to remove the stain and smell.

Using deck bleach to remove dog pee

A word of caution, bleach literally bleaches the wood. Over application can result in lightening the wood. Creating the opposite effect of urine. Instead of dark spots on the deck, you will have light spots where you applied the bleach. Chlorine bleach can also break down the wood fibres damaging the decking when over-applied. Along with destroying or killing the surrounding greenery around your deck.

But if your wood deck is unusable because of the stench of dog urine and unsightly marked bleach will be your best solution. I would recommend you integrate bleach cleaning with staining your deck. Power wash down the decking. Bleach the entire deck creating a clean and consistent lighten wood. Then after cleaning off the deck bleach and cleaner, let dry and seal the deck with a fresh coat of stainOpens in a new tab..

Annual bleaching your entire wood deck will not negatively impact the decking, but if you are pouring bleach on your deck every time Grover pees, it will be a problem. Use vinegar or baking soda for immediate cleaning and save the bleach for cleaning off the entire deck. After repeated peeing on the deck.

Never use chlorine bleach on composite decking. Bleach on composite decking can cause premature chipping and cracking, damaging the structural integrity of the decking. Also, chlorine bleach can corrode metal fasteners. There are deck cleaners designed for composite decking, pay the money, buy the right cleaner.  

Conclusion of dog pee damaging decking

Dog pee will damage your deck, especially wood decking. The best remedy is immediately cleaning the urine off the decking. In extreme circumstances, heavy-duty cleaners may be needed to remove the strong smell of urine from your deck. The most damaging effect of dog pee on your deck.

Keep a watchful eye, clean up as soon as you notice a problem. If you do that, you should be able to enjoy your deck for years to come with your best friend.

Ryan Nickel

A Red Seal carpenter, passionate about building decks to be enjoyed.

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