How to Remove Old Deck Stain

Removing old deck stain can be extremely difficult. In this article, we will cover when to remove deck stain, situations where it may not be needed, and how to remove well-adhered deck stain.

When to remove deck stain

Removing old stain is necessary if a deck is being restained to a lower transparency, if the current stain is transparent stain but you are switching to a different color, or if the old stain is failing completely across the entire deck. These are really the only situations where complete stain removal would be necessary. 

Different transparencies of deck stain. More opaque stains generally require less prep to look good.

Situations where complete removal is unnecessary

Complete removal of old deck stain is almost always unnecessary. If staining with the same transparency or if you are going more opaque (like from a semi-transparent to a solid stain), if the stain failure is localized to a few areas, or if the existing stain is otherwise in good shape, stain removal will be a pointless and very time-consuming task. This is what we find in most of the deck projects we work on. Small areas may need scraping or sanding, but oftentimes not the entire deck’s surface.

This deck is in rough shape but has a solid stain. Assuming the homeowner chooses another solid stain, complete removal is unnecessary but scraping will be needed.

Many customers have the desire to move down to a transparent stain but the costs associated are generally enough to dissuade many homeowners from moving forward with it, as it can take multiple days of work, even for an average-sized deck.

A well-prepped deck will oftentimes still have some stain adhered to the surface

How to remove well-adhered deck stain

Stain removal is possible through chemical and abrasive methods. In general, abrasive methods always work, while chemical methods are very hit-or-miss.

Chemical methods of deck stain removal

Solvent or Citrus-Based Cleaners: Products that incorporate natural solvents (such as d-limonene found in citrus-based strippers) can be effective at breaking down the stain while being less toxic than traditional chemicals. At EcoWash, this is oftentimes what we use. CitriStrip is sometimes a useful product when combined with a pressure washer.

Deck before chemical strippers were applied

Specialized Deck Stripper Products: Many commercial deck strippers combine caustic chemicals with surfactants to help lift the stain from the wood surface. These are formulated specifically for the task and are designed to work on multiple types of stains. Sherwin Williams Stain & Sealer Remover works somewhat well when combined with a pressure washer.

Deck after stripper applied, and a pressure wash. Note that not all stain was removed, but most was.

Alkaline-Based Strippers: These products often contain sodium hydroxide (lye) or potassium hydroxide. They work by breaking down the stain’s binder, making it easier to remove. Because they are highly caustic, proper protective gear (gloves, goggles, and long sleeves) and careful application are essential.

Acidic Solutions: In some cases, acids like oxalic acid can be used, particularly when dealing with tannin or rust stains. However, they may be less effective on resin-based deck stains and require neutralization after use.

Regarding the chemical removal of deck stain, we encourage you to be less enthusiastic about the expected result. Oftentimes the chemicals do not work or work less than expected. Tanner Scherer, a Region Manager at EcoWash servicing Milwaukee and Chicago, has this to say about stain removal chemicals:

“Don’t even try, just sand it”

Well put, Tanner.

Physical methods of deck stain removal

Scraping, sanding, and pressure washing are the most common physical methods for stain removal. For very tough stain, a grinder with a specialized paint removal attachment is the best thing to use.

Same deck as above, after chemicals & during sanding

Scraping is best for small areas and to remove very loose, flaking stain. This is the most common method of stain removal and is highly effective, although labor-intensive. Scrapers can be push scrapers or pull-scrapers, with some pull scrapers being able to attach to a handle which is a much easier and less straining way to remove stain.

Deck shown above after chemicals, pressure washing, and floor sanding with 20-grit paper

Sanding is effective if a large floor sander is used with a very low-grit sandpaper. A 20-grit paper is most useful and a large orbital sander is required for this type of job. A small handheld sander will not be effective for this type of work.

Pressure washing is useful in combination with a chemical stripper. After the stripper sits for the recommended amount of time (generally 5 to 15 minutes) pressure washing will remove and dilute the chemical used as well as physically remove the stain. This is not as thorough as sanding or scraping unless combined with a chemical.

A grinder with a paint-stripping disc is an aggressive and sometimes necessary option. This can be expensive, but for tough areas, we have seen it work well. We would generally stray away from this option unless other ideas have been exhausted, as it could damage the underlying wood.

All in all, deck stain removal is a difficult process with inconsistent results. At EcoWash, we encourage homeowners to explore options that do not require complete deck stripping. A solid stain is oftentimes the correct option, and Sherwin-Williams has fantastic options and a variety of colors to choose from.

If you are in search of a professional deck staining company in Madison, WI, contact EcoWash today.