How to Clean a Wooden Deck Around Your Hot Tub?

It’s that time of year again. Weather is starting to get better so it is time to think about cleaning the deck around your hot tub. That is what I plan to be doing this weekend so I thought that it would be quite fitting to write this week’s blog post on the subject. Before you get the power washer out, and blast the hell out of the wood, sit down for a few minutes, have a cold one and have a read of this blog post.

Don’t Power Wash Your Deck!

It may be the obvious thing to do, but believe me, you don’t want to power wash your deck. There does seem to be mixed opinion on this and I must be honest, I have power washed my decks before. That said, I will explain a new found “tool” which is much more effective, quicker and better for the wood later in this article.

Wood decks are especially vulnerable to power washing, because the pressure exerted by the power washer can lead to splintering. If there is any area on the deck where the wood is already beginning to split apart, power washing it will exacerbate the problem and cause the split area to expand.

Wood isn’t the only decking material that can be permanently damaged by power washing. Softer materials, such as PVC, can essentially be ‘engraved’ by a power washer if the pressure is set too high.

It’s also a bad idea to use a power washer on a composite deck because the power washer can actually take chips out of the composite material. To make matters even worse, damage caused by power washing is not typically covered in the warranties for composite decks, so if you do damage your deck beyond repair, you’ll be paying out of pocket to fix it.

The older the deck, the worse the wood reacts to pressure washing.  The big mistake is that companies and homeowners have a tendency to set the pressure way too high.  But even at low pressures the deck can become damaged.

What does pressure washing do?

  • It removes loose material and leaves a gafillion dangerous splinters and gaps.  Those gaps open up further letting in more damaging sun and water.
  • It removes the natural oils in the wood that are not replaced with sealants.
  • It causes wood to dry quickly causing cupping and warping.
  • It causes damage.
  • It loosens nails as the wood expands.
  • It can cause water to enter the house.

What is the alternative?

Chlorine Bleach? NO!

Bleach is the old standard used for years in cleaning. On hard, nonporous surfaces, a chlorine bleach solution is an effective sanitizing product that kills mold and neutralizes indoor mold allergens that trigger allergies.

On wood, however, the chlorine kills algae, moss and mildew. But it breaks down the complex organic polymers (or lignin) that hold the wood together, causing excessive damage to otherwise healthy wood. Chlorine is dangerous, environmentally unsound and likely to cause damage to your surrounding greenery.

The corrosive effects of chlorine bleach on wood decks are cumulative and are more numerous than you might imagine. Bleach literally bleaches the wood, resulting in a lightening of wood’s natural coloration. This bleaching effect may provide initially pleasing results, but over a period of several months the wood begins to take on a lighter appearance. The natural pH of wood is just slightly acidic, and bleach is a basic solution. As a result, use of bleach on wood shifts the pH from wood’s natural, near neutral pH to a basic pH that will damage the cellular structure.

As a cleaner, bleach provides minimal results. The natural bleaching action creates the impression of a cleaner surface which, in reality, is only bleached but still needs cleaning. Cleaning with bleach does kill mold and mildew that may be on the deck, but it does not eliminate the spores from which mold and mildew grow.

Not only does chlorine bleach break down wood fibers and alter the color, it also corrodes metal fasteners, including the screws and nails holding your deck together.

So What is the Answer? What is the “tool”?

I only found this little gem this year and I am very impressed. Oxygen Bleach!

Oxygen bleach (or sodium percarbonate) is an excellent detergent and bleaching agent with a hydrogen peroxide base. At a normal temperature, it’s a good cleaning and bleaching agent and has strong fungicide effect. For instance, fruits and vegetables treated with sodium percarbonate can be kept fresh and stored for a longer time. In medicine, it can kill bacteria like staphylococcus and colon bacillus.

This product is a white particle powder, nontoxic with no contamination, nonflammable, nonexplosive, easy to get damp and soluble in water. It is efficient, safe and economical. It’s also biodegradable and leaves no harmful by-products or residues that can harm the environment. Except for industrial-strength cleaning or stripping jobs, sodium percarbonate is, hands-down, the choice for most average wood preparation jobs. Your first line of attack is undiluted hydrogen peroxide that is an oxidizing agent (just like chlorine bleach) and should kill the mildew on contact within several minutes.

How do you Apply Oxygen Bleach?

Step 1

Mix 1 cup oxygen bleach power and 1 gallon (5 litres) of water in a cleaning bucket.

Step 2

Rinse off your deck with the garden hose to loosen debris and buildup.

Step 3

Dip a nylon scrub brush into the water and oxygen bleach mixture and scrub it over the deck. Continue across the deck until the entire unit is cleaned to your satisfaction. Let it sit for 10mins.

Step 4

Rinse off your deck once more to wash away all of the lifted buildup, and let the deck air dry.

Job done – now you are ready for oiling  again!


Content References


Can I Help You?

If I can help you in any way I would love to hear from you. You can get in touch using the form below.

Thanks - Andi


Hi, Andi here. I own and also write all of the articles and info pages on the site. Some years back now, I built my own hot tub but struggled to find the information I needed. So, once my tub was complete, I started this website to help others in their own pursuit of hot tub and plunge pools DIY building information.

Today, I've helped over 1000 DIY customers just like you all over the world build hot tubs and pools. Have a good look around the site, there are lots of resources here. Please do get in touch if I can help you. - Cheers, Andi

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