Tips for Power Washing Dirty Decks, Siding and More

We are at the end of a long dark winter, and it’s a relief to be walking through my neighborhood and seeing windows thrown wide open and flowers planted in pots by front doors up and down my street. But I also see lots of dirt and grime – remnants of salt, sand, wind and dirt – left behind by six months of old man winter (and a reminder that we survived yet another harsh one).

I remember using a scrub brush as my main tool for outside spring cleaning in the early years. That is, until we decided to rent a power washer to clean the siding. My husband, a guy’s guy, rented a high-power commercial cleaner, and when he was done, half the paint on my siding was stripped away. An unnecessary and expensive learning experience!

Since all my lessons seem to be learned the hard way, I decided to share what I learned with those who are looking to spruce up their yard this spring:

 Lesson 1

Buy a power washer with several settings, and forget about commercial strength (it’s really not necessary).

• Pressure washers run as low as $400 and can go up to $2,000. When I went to buy mine, I chose a general purpose, lightweight gas model with 1600 psi (recommended by the clerk in the store).

Lesson 2 Power Washing Siding

Unless your siding is incredibly dirty, there is no need for detergent. I simply use water to rinse off the dusty walls.

• Wash from the bottom up, and rinse from the top down. Like washing an interior wall, starting at the top has the water running down the walls, and could result in streaking.
• Hold the gun about 10” from the siding, and spray at a downward angle. Don’t use too much pressure (I speak from experience here) – it can cause real damage.
• Spray carefully around doors and windows – keep the nozzle turned down and away.
• If you have mildew on your siding, make sure you cover plantings and flowers before you add bleach to these troublesome areas.

Lesson 3 Power Washing a Deck

I can’t wait to sit on my deck with a glass of wine, but my deck needs a thorough smackdown before my furniture is ready to be put out.

• For a newer deck, use a stiff synthetic bristle brush with a long handle, and a bucket of warm, sudsy water for the first step in deck cleaning. Wash it like you would your kitchen floor – depending on how dirty it is, you may have to do this twice. Change the water in your bucket often!
• Older decks need more TLC.  Hirshfield’s carries a wide selection of cleaners, brighteners, strippers, and wood restorers. Stop by one of their locations and let them help you pick out the product you’ll need to clean or restore your deck.
• Finish the job by power washing the soapy water off the deck. Keep the trigger away from the surface and use medium pressure in order to wipe away the water without damaging the wood. Use a consistent “sweeping” application in order to prevent lap marks, and don’t have the nozzle too close to the deck (again, to prevent chipping and damage to your deck).

Lesson 4

Inspect your work before you pat yourself on the shoulder. Your deck should look consistent – no areas unwashed or over-washed, and it should look clean with minimal or no “lap” marks.

• Let your deck dry for 24 – 48 hours before applying a topcoat. Wind, humidity, and temperature are factors that affect the drying time.

For help with power washing products, not to mention stain and sealant, visit our local Hirshfield’s locations in Minnesota, Iowa, Wisconsin, South Dakota, and North Dakota.

Since Frank and Elizabeth Hirshfield opened their first store in 1894, it has been our mission to do the best job possible meeting customer needs and solving customer problems. Hirshfield’s. People and products you can trust.