Cleaning a deck? Why you probably shouldn’t pressure wash it
Having a clean deck makes those summer night all the more enjoyable. Restoring the surface of your deck can be a very DIY friendly project as most of what is involved is elbow grease and attention to detail. That being said, it can be a full day commitment or longer depending on the size of your deck so depending on your schedule it could be worthwhile to have it done by a professional. Your deck is likely finished with wood or composite deck boards, and this is important because the material will dictate the best way to clean the deck. If your deck is wood its probably either pressure treated wood or cedar (there are other materials such as IPE and other exotic woods, but they are far less common), and if your deck is composite it could be from a plethora of different suppliers, all with small differences.
When it comes to a composite the best plan of action is to look at what is recommended by the manufacturer of their product. In many cases they will have detailed instructions and even products to use created by them. That being said composite decking does a much better job of staying clean because it is not porous like wood, instead the colour of the decking may fade over time which is not something that can be cleaned but this is a long process and wood is susceptible to this as well.
Going back to wood decks is where there is a little bit of debate, specifically regarding whether to pressure wash or not. Many people have pressure washed their deck and have been happy with the results, as the high pressure water is usually able to easily remove the layer of dirt and grime that is built up on the deck. What many people don’t realize is that when pressure washing a deck you’re going to be removing more than just dirt, specifically you will be taking off some of the wood from the deck. Because wood is composed of fibers the high pressure of the water can remove small layers. This may be hard to notice initially and is why many people are satisfied after pressure washing their deck.
What removing this top layer of fibres does is make the deck slightly rougher which will only attract more dirt and grime in the future, as well as shortening the overall life span on the deck because of the removed material. Modern pressure treated wood is often not soaked all the way through, hence why cut ends need to have sealer applied. This means repeated pressure washing may actually remove the coating may the wood much more susceptible to rot. This is where the elbow grease comes in, as a proper cleaning in a way that does not damage the wood will require some scrubbing. Using a scrubbing brush or broom (not metal or wire!) along with either soapy water or a cleaning product is what we have found to be the best for cleaning a deck. Be sure to read the labels of the product you choose, some will contain bleach or other whitening agents which can stain clothes or leave spots on the deck if you are not careful.
This can take a few passes but the best way to approach the task is systematically, start in one area and work in an organized path to ensure you clean the entire deck. Scrubbing will bring out the dirt and grime on to the surface of the deck and dirty your water very quickly, constantly rinsing the area will ensure these dirt puddles don’t build up and leave weird stains. As you repeat the process the wastewater should become cleaner with less initial dirt on the deck, this is how you will know you are progressing. And really that’s it, you don’t need fancy gadgets or expensive tools to achieve clean deck. Just some hard work and free time. Once your deck is cleaned you can leave it be or look into different finishes or sealers which will be discussed later. Get your deck ready for relaxing, keep your home happy!