How To Prep Before Power Washing Your Deck

There's something so satisfying about watching a power washer remove the muck, caked-on dirt, and algae on the surface of a deck. While using a power washer to remove grime like this looks fun in all of those videos online, to get those results, you need to take a few extra steps to prep. The basics include preparing the pressure washer by checking the hoses and filter and then choosing the best nozzle for the job. Take a look at the owner's manual, too, to make sure you know how to properly use the system. You should also make sure you're addressing the surface of the deck by removing any loose material and using a pre-treat for stains or highly damaged areas. 

A bit of pre-work may mean protecting your deck and potentially prolonging the life of the wood or other surface material. Often, this process takes some time but can reveal the beauty of the wood underneath the surface layer when done well.

Most manufacturers require users to perform several preventative maintenance steps on their power washers. Read the owner's manual and follow all directions included there. Typically, this involves checking the inlet filter for buildup. To find it, look at the spot where the hoses fit into the pressure washer. This is the pump box, and the water inlet filter is located just beyond it. It should be clean and, if not, remove and replace or rinse it. This protects the pump from contaminant-related damage. Next, check the actual hoses. These should be in good condition with no damage to the exterior. They should fit snuggly into place and, with a light tug, should not come off. Any other accessories you're using, such as attachments, should also be tightly in place.

You'll also need to choose the right nozzle tip for the job, as this controls the amount of pressure and the cleaning method. Most of the time, a 40-degree nozzle tip is a solid choice for any type of basic cleaning task. If you're cleaning a concrete or brick patio or steps, you'll want to choose a 25-degree nozzle tip instead. If you plan to stain a wood deck after power washing, consider a 15-degree nozzle tip, as that will remove the most embedded dirt. Before applying to any surface, always check the function and pressure of the nozzle on a hidden surface of your deck. Don't use anything that damages the structure.

Before flipping on the power washer to get to work, remove anything from the surface of the deck that could suffer damage or blow away. That includes all stones and loose material. Sweeping the surface helps to minimize this risk. Also, be sure to close all of the windows and doors around the area, put on eye and ear protection, and keep pets and kids inside during the process. Be sure to wear pants to protect your legs from material that will have a pretty powerful trajectory when it comes off.

For surfaces with substantial buildup of algae and grime, you can pre-treat it using a specialized product available at the home improvement store. Choose the chemical best suited for the material of your deck, such as wood or composite-based products or a specially formulated, non-toxic version. You can also use a mild dish detergent on the surface and spread it over the area with a brush. Though you can also use bleach-like products, only select those designed specifically for this type of application to protect the environment. Let any application of treatment sit for a few minutes before power washing. You may wish to use a scrub brush to get in between spindles on the railing or into the crevices. Then, when power washing, be sure to rinse the surface fully.