Power washing wood decks with a pressure washer is all part of the prep work needed for wood deck maintenance. It is a fairly simple but tedious task. Power washing a deck can take one hour or many hours depending upon the size of the wood deck and the condition it is in. You will need to know what type of pressure washer to use and the correct amount of pressure (psi – pounds per square inch) the pressure washer should be so the wood does not get damaged.

Power Washing Wood Decks - Open Wood Pores, Remove Mill Glaze, Mildew and Grey Coloring

There is another purpose to power wash your wood deck other than cleaning off the surface of the wood from dust, dirt, mildew and stripping of any old finishes like stain, paint or clear coat sealants. Power washing a wood deck properly will cause the natural pores of the wood open up, allowing for the stain to absorb deeply into the wood. Most new wood decks will most likely have a mill glaze on the surface. Newly constructed wood decks should be power washed which will remove the mill glaze and allow for proper penetration of the stain. Wood decks from being weathered can also turn an ugly grey color which power washing can remove as well.

Power Washing After Sanding Wood Deck

Sanding a wood deck surface is an excellent way to prepare the surface of a deck, which would require power washing after the sanding is complete. This will wash away any dust and open the pores of the wood. When sanding a Deck you do not need to use any wood deck brighteners or cleaners. A pressure washer between 1000-1200 psi is plenty strong enough. Pressure washers come with different types of spray nozzles, usually in different colors. You will want to use the widest spray nozzle, 40 degree, at 12 inches off the surface of the deck. You should always keep the gun moving in a pendulum motion once the trigger has been pulled and when you need to stop remove your finger from the trigger.

Power Washing Wood Decks with Brighteners and Cleaning Chemicals

You can power wash a wood deck with brighteners and cleaning solutions which can remove most stains and mildew. Solid colored stains and paint will need different methods for removal. Solutions are mixed in buckets and applied by hooking the small hose from the pressure washer to the bucket and sprayed onto the surface. Then with large deck brushes the surface can be scrubbed, always scrubbing with the grain of the wood. This can then be rinsed with the pressure washer. The pressure washer can be between 1500-1800 psi and a 25 degree spray nozzle, 12 inches from the surface.

Power Washing Wood Deck without Cleaners

Decks can be prepared with just power washing alone but the pressure washer must be more powerful and held closer to the deck surface. Care must be taken to make sure you do not damage the wood surface when using higher psi pressure washers, smaller degree spray nozzles and being holding the nozzles closer to the surface of the wood. For power washing without cleaners a pressure washer of 2000-2500 psi with a 25-15 degree spray nozzle at 8-10 inches from the surface will remove stains, dirt, mildew and a good amount of peeling paint or stains. For paint and solid stains some sanding afterwards is recommended with repeated washings.

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