How to Pressure Wash a Fence

Fences are a great addition to any home. They keep pets in the yard, help prevent children from running into the street, and provide privacy from neighbors. However, being exposed to the elements 24 hours per day, 365 days a year, can take a toll on a wood fence. 

Fortunately, a pressure washer can turn back the hands of time and make an old wood fence look like new again. All it takes is the right tools and a little technical knowledge. 

Before Getting Started 

The first thing to remember is that there is another side to a wooden fence; whether it faces the street, a neighbor's house, or the wilderness, it is essential to know what is behind the fence at all times for proper safety. Pressure washers can cause harm to people, animals, and plants—even through the holes of a wooden fence. A few other things to keep in mind before cleaning: 

• Remove tripping hazards, plants, animals, and other obstacles from the area 
• Close doors and windows, if applicable. 
• Choose the proper spray tip and accessories for the job. Avoid using the zero-degree tip and consider using a turbo nozzle, for example. 
• Be aware that pressure washing a fence will inevitably lead to water runoff. 

Clean With Detergent First 

A fence should be lathered with detergent or soap before cleaning, especially if green moss, mold, bird droppings, or other baked-on stains have formed. This makes the cleaning process easier and yields better results if the fence is to be restained or refinished afterward. 

Pro-Tip: Before cleaning, spray down surrounding foliage to saturate the soil prior to using detergent. This encourages the runoff of detergent water to prevent harming plants. 

To get started, work in sections. Start from one end of the fence and wet the first section of fencing. Then, switch the pressure washer's detergent tank to "On" and begin applying detergent from the bottom up to avoid streaks. The detergent should settle for 5–10 minutes to give it time to work. Water should be added continually to any areas that start to dry. 

Especially dirty spots may need to be washed using a rotating scrub brush. The soft inner bristles of the brush are propelled by water pressure from the power washer and will easily remove heavy stains. 

Rinse Using a Pressure Washer 

A low-to-medium pressure spray pattern should be used when rinsing the detergent. Wood is soft, so damage or surface streaking must be avoided. A fan pattern with moderate pressure is a reliable choice for covering medium- to large-sized areas. 

Switch the detergent tank to "Off," then squeeze the trigger to flush out any remaining detergent from the lines. Starting from the same part of the fence where the detergent was first applied, work from the top down to rinse all soap from the fencing. Work with the grain of the wood, covering one to two boards at a time in identifiable sections. 

The detergent application and rinsing should be repeated for each section of fencing. Applying detergent to the entire fence before rinsing may cause the soap to be absorbed and dry onto the wood before it can be rinsed off. The detergent should remain wet until it is rinsed away to prevent spots and streaks. 

Apply Paint or Sealant 

After pressure washing, the fence should dry for at least 48 hours. This allows enough time for absorbed water to evaporate so it does not get sealed into the wood. 

Once the fence is fully dry, it is important to paint or seal it to prevent damage from the sun and wind. The fence can be painted for a bright new look or sealed to allow the wood grain to show through. 

The boards should be fully sealed, including the edges and gaps. While boards on privacy fences may be too close together to seal between them, sealer should be spread into the grooves to cover as much exposed wood as possible. 

After the sealer is dry, the fence will have a refreshed appearance. Regular pressure washing of the fence will keep it looking new. While fresh paint or sealant is not required every year, it should be reapplied every few years to maintain protection. 

How to Clean Vinyl or Metal Fences 

While there are different types of fence materials, the principles of cleaning them are almost universal. The operator should work in sections, soak the fence in the proper detergent for the material, allow time for it to work, and then use the pressure washer to rinse the fence clean.