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Pressure Washing vs Sanding a Deck, Which is Better?

Pressure washing and sanding can both be important aspects of preparing a deck for a staining project. While the two can be complementary, they also can be used interchangeably to remove old coatings. In this article we will talk about the purposes of pressure washing a deck before it gets stained, the purposes of sanding a deck before it is stained, when pressure washing can replace sanding, and what we recommend.

The purpose of pressure washing a deck

Pressure washing is very important prior to a deck staining project. Pressure washing removes unwelcome materials from the surface such as dirt or algae, removes the delaminated lignin layer from the surface of the wood, and removes any flaking stain. Pressure washing can also help to open the pores of the wood and increase its ability to absorb stain.

However, pressure washing should be done carefully and by a professional. Improper washing can irreparably damage the surface and cause splintering or result in a “peach fuzz” due to the lifting of the wood grain. These should be avoided, but should not discourage a homeowner from getting their deck washed before a staining project.

To learn more about pressure washing a deck, read our article on it here.

pressure washing composite decking
Pressure Washing a Deck in Sussex, WI

The purpose of sanding a deck

Sanding a deck can be important prior to a deck staining project, but is not always important. Sanding smoothes out a surface and can help to remove old, flaking stain. A smooth surface can be pleasant to walk on and old stain should be removed prior to a deck staining project. For more on stain removal prior to a deck staining project, read our article Do I Need To Completely Remove Old Deck Stain here.

While sanding may sound like a good way to spend you time to ensure a nice-looking end result, this is often the opposite. Sanding wood results in an abundance of sawdust and this will clog the pores in the wood. These clogged pores result in less surface area for the deck stain to absorb into and a worse, shorter-lasting, and less impressive finish. In addition, a deck floor does not really benefit from being smooth as it will get slightly warped and dented over time.

Sanding can absolutely be necessary for a deck staining project but it should not be overdone, if needed.

floor sanding a deck
Floor sanding a deck in Lake Mills, WI

When pressure washing can replace sanding

Pressure washing can replace sanding completely if there is no flaking stain. Pressure washing is generally better at removing stain, dirt, or algae from a deck surface and can remove the delaminated lignin layer from the wood without clogging the pores. Sanding is generally not recommended on projects without failing stain as clogging wood pores will dramatically worsen the finish.

What EcoWash recommends

EcoWash recommends pressure washing for all deck staining projects and sanding for those that have failing stain. If sanding must be done do it sparingly and only in areas where it is needed to avoid excess dust. 

If you are a homeowner in need of help with a deck staining or deck preparation project, get in touch with EcoWash today.


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