How to Clean Stained Siding with a Pressure Washer
When you use a pressure washer on stained siding, your goals are simple: Take away accumulated dirt and old stain, and get the wood’s pores to open. If you hope to re-stain wood trim and siding, and the undersides of roof overhangs, pressure washing is the first step. Any wood siding can withstand pressure washing provided you use the appropriate techniques. The nature of the previous stain and the one you wish to apply will influence how you go about pressure washing wood siding.
Things to Keep in Mind
Pressure washers can be hazardous in the hands of the unskilled. Though you’re more likely to harm your siding than another person, it’s vital to follow procedures clearly. You’ll want a pressure level of 2000 psi or more, and an output of between 3 and 4 gallons per minute. In other words, your washer should pack a punch.
Matching the right nozzle to each part of the job is important. A nozzle that creates a 40-degree fan reduces the chance that you’ll damage the house. Spots that are more resistant to cleaning, on the other hand, may require the force of a 25-degree nozzle. Neither a 15- or zero-degree nozzle is suitable for working with stained siding; both are too powerful.
How much washing does wood siding need? Three factors determine the answer: What kind of stain is currently on the wood, what shape the siding is in, and what color the new stain will be. Specifically, moldy siding demands more washing, as does stain that has begun chalking. Stain that is lighter than what is presently on the surface is unlikely to cover up imperfections. All of these issues are good to keep in mind when estimating how much work a pressure washing job will require.
Dealing with Mold
Bleach and water are the way to tackle mold. The solution should sit on the surface for up to 20 minutes. Alternatively, a store-bought cleaner can be added to the pressure washer.
Getting Rid of the Previous Stain
Stain that has been on an exterior surface for a while has generally sustained a lot of sun damage, which makes it powdery. This stain residue can be removed with a stream of water from a pressure washer. A cleaning solution is rarely necessary, since stain is easier to get off wood siding than paint.
What Color Stain Should You Use?
If you want to apply light-colored stain to a surface that was previously treated with dark stain, the latter will have to be taken off completely. A wood exterior must be pristine to receive light stain; any leftover dark stain will alter its color. As noted earlier, pressurized water alone may be enough to eliminate the old stain. If it doesn’t suffice, load the pressure washer with a cleaning or stripping solution. Keep in mind that cleaners add to your project budget and make a job take longer, since they must sit on surfaces and then be rinsed off completely.
As you might expect, if the stain you’re applying is darker than its predecessor, you don’t have to be as meticulous about removing the latter. Once you’ve gotten rid of loose stain, and the majority of the previous stain’s hue, you’ve done your job. If the exterior is porous and reasonably clean, the new stain can truly permeate it.
Stained Siding and the Essentials of Pressure Washing
Cleaning exterior wood siding requires unique methods, as we’ve discussed. However, some aspects of pressure washing are universal. If you learn and act on these fundamentals, you’ll avoid causing harm to your house.
Before pulling the washer’s trigger, make sure that windows and doors are shut tight. Don’t point the stream of water directly at the windows; focus instead on whatever dirt the siding has on it. Try to keep the water away from leaky windows.
Be similarly cautious around electrical sources, like outlets or lights. If you take a light fixture down before pressure washing, make sure to fill the resulting hole with something water resistant, like plastic bags, to prevent too much water from entering the building.
Avoid sending water into gable vents or the undersides of roof overhangs. Even when washing siding, don’t let the stream be perpendicular to the surface. Hit it at an angle, from at least 2 feet away initially. Washing at closer range, or with a straight-ahead blast, could harm the siding.
Once the washer is active, you can approach the exterior slowly. It’s still unwise to get closer than 10 inches, however. When it comes to directing the stream in a washing motion, the wood grain should be your guide. Maintain continuous motion to avoid damaging the surface.
Pressure washing stained siding with a cleaner is a bottom-to-top operation. The solution’s container should indicate how long it should be allowed to sit on the surfaces being cleaned. Rinse the top of each surface first, then make your way to the ground.
In contrast, do a fast wash starting at the bottom when using only water. The idea is for the exterior to absorb some water before the second round of washing, which proceeds from the highest point of each surface to the lowest. In this way, the average stain can be washed away. If stain residue remains, do another round from top to bottom.
The aforementioned guidelines are useful in many circumstances, for many home exteriors, but every surface is different. Notice how easily the stain is disappearing from your siding, or how stubborn it’s being, and adjusted your technique accordingly. To an extent, pressure washing is about following directions, but it’s also about trial and error and following your intuition.