Rewrite by Terri Perrin / Published September 2021
Contributors: Donna Hillyer, President/CFO; & Rick Hillyer, Vice-President/General Manager of Petersburg Power Washing Inc., Petersburg, IL
This was previously updated in 2012 and revised from the 2002 Power Washers Guidebook article, originally written by Tom Burns, president with All Ways Clean Manufacturing, Aurora, OH, and later revised by Manzie Lawfer with Blue Skies Pressure Washing, Louisville, KY, and Jonathan Whitt with Lynchburg Pressure Wash, Lynchburg, VA.
There’s an old saying … “Home is where your story begins.” This might be true for individuals; however, when it comes to the business of power washing houses, “Home is where your story may get a little complicated!”
When it comes to house washing, there are a myriad of factors to consider with any potential job. From climate and weather conditions to pollution, types of siding, and roof finishes, to regional architectural differences, there is no single magic formula for working in this sector of the pressure washing industry. High-pressure cold water may work well on homes in Phoenix, AZ, for example, but in Charleston, SC, homes are subject to mildew and may require prepping with a bleach solution at low pressure and a high-pressure rinse. Homes in Billings, MT, are easier to clean than those in Pittsburgh, PA, because they are not affected by industrial pollution. Moss can be a huge problem in some areas and not at all a concern in others. Do your due diligence to understand the challenges in your region.
There have been considerable advancements in power washing equipment, chemicals, and techniques over the past 20 years that enable contractors to complete cleaning jobs more quickly and effectively. Generally speaking, there are two tried and true methods of house washing that work well across the country. For most homes, a hot water wash using a slightly alkaline detergent boosted with some type of mildewcide works fine. (Mildewcide is an effective mildew treatment that can be used with all interior and exterior latex-based paints as well as oil- and solvent-based paints, stains, coatings, and adhesives. This product will resist mold, mildew, and algae while also minimizing discoloration.)
For homes exposed to air-borne pollutants or with heavy oxidation present, a two-step process that deploys an acid-based cleaner followed by an alkaline detergent is recommended. (See below.)
Just as your choice of equipment and techniques may vary from home to home, personnel allotment also depends on the job at hand. If roof work is required, for example, there must be a team leader with an assistant. Moreover, a contractor must use OSHA-approved safety equipment to tie off when necessary. For safety, always send someone to be a ground assistant when an employee is performing high work. Make ladder safety training part of your corporate culture.
Thanks to advancements in equipment technology and chemical formulations, situations where you have to physically get onto a roof to clean it are almost non-existent in today’s world. Ladders and wands with extension poles and specialized pumps often enable contractors to spray the roof from the ground. (This is also better for the longevity/integrity of the roofing materials.) Always wet down the surface before applying any detergent. If detergent is applied to a dry surface, streaking may occur.
Be aware that many customers worry about their landscaping—and rightly so! It is important to use products that are environmentally friendly and to use a light shower wand and a garden hose (not high psi) to water down plants, flowerbeds, and shrubbery in advance, so they don’t absorb chemicals that may be used in the pressure washing process. Once the job is complete, lightly rinse the plants with the garden hose again.
While we are not able to power wash homes in some climates in the dead of winter, be mindful of your footing and icy patches if you do complete any work in the winter.
Petersburg Power Washing’s trucks, for example, are set up with a minimum of 200 ft. of high-pressure hose. They use various lengths of wands (two, four, and six ft.) and 24 ft. extension poles for high work. X-jets are used for detergent application, and various sizes of step and extension ladders are available for high work. X-jets enable you to apply chemicals or detergents with less starting and stopping and reduce personnel needs.
Commercial grade, gas-powered, hot water washers at 3500 to 5000 psi with 6.5 gallons per minute work well. Adjustable pressure wands allow operators to dial down or up the pressure as needed, combined with a mixture of alkaline-based detergent with chlorine additive as well, when needed.
In the past, our industry typically removed dirt and grime from roofs with high pressure (which, in some cases, also increased the risks of surface damage.) Today, the industry is changing from “pressure washing” to “soft washing” techniques with more touchless/brushless/soft washing equipment being introduced. Advancements with different types of detergents also now do most of the work for you. Methods have certainly changed with roof washing, as the detergent is now recommended to stay on the roof substrate for a couple of weeks where it continues to work to eliminate any type of moss, acid rain, algae, or mildew than was left behind after washing. The method keeps the roof cleaner for a longer period of time.
A general-purpose, slightly alkaline detergent works fine most of the time. A chlorinated detergent may be used to expedite the cleaning of surfaces with excessive mildew. Hot water increases both the speed and effectiveness of the job.
A two-step chemical process relies on an acid-based detergent cleaner and an alkaline-based detergent. The acid-based cleaner (active ingredients—hydrofluoric, sulfuric, and phosphoric acids) react with oxidized paint, loosening its bond to the hard paint, and move pH (acidity level) on the surface to the acidic range.
The alkaline-based cleaner (active ingredient—potassium hydroxide) is then applied before the acid-based cleaner dries. This swings surface pH quickly to the alkaline range that further loosens the oxidized paint and dissolves both pollutants and oxidized paint. Applying these two chemicals correctly eliminates physical scrubbing of the surface.
Let the homeowner know you have arrived and ask the homeowner politely to keep children and pets inside.
Remind the homeowner to shut and lock all windows and to towel-pad any openings that may leak, such as sliding doors.
If the homeowner is not home, double-check to ensure that all windows are closed.
Safety scan—walk around the house and move obstacles.
When you are satisfied that the site is ready, unload your equipment.
For convenience, set up the two ft. through six ft. wands with quick disconnects into the high-pressure gun. The 12 ft. wand used with an extension pole, if necessary, cleans areas over one story. An alternative is the extension pole with a built-in hose/gun assembly.
Use a ladder only in accordance with OSHA rules.
Wear appropriate personal protective equipment (PPE) to protect your eyes from spray and your feet from substrate slip hazards.
From start to finish, be attentive to all environmental regulations. Wastewater runoff and lead-based paint are particular concerns.
Follow the wastewater disposal requirements for the jurisdiction of the job site. If you are working on a house painted or sided before 1976, have it tested for lead and follow procedures for safe disposal.
Start and adjust the pump, water temperature, and chemicals. A 3000–5000 psi-range, 4 to 7-gpm pressure washer is the standard size of equipment for this type of cleaning. House washing is probably one of the only wash applications where hot water is not absolutely necessary, but as always, hot works best.
A quality downstream injector, particularly one designed for two-chemical switching, allows for the application of detergents and rinsing without extra labor or running back and forth to switch soaps. (The initial injector setting is usually 60–80 parts water to one part chemical.)
Cold water is preferred by many experts because it will not cause condensation on the inside of the siding or expansion of the siding and window material. When hot water is used, stay below 160°F. Using lower pressure (2000 psi or less) protects against damaging the surface.
Start on an inconspicuous part of the house (back of the attached garage, if possible). Modify your approach according to results obtained on the first part completed.
When using only detergent, apply the soap solution starting at the bottom and working to the top. Allow enough dwell time for the detergent to do its job and to lift the dirt to the surface, but do not let the soap dry on the surface.
Rinse from the top down. Flush the surface of all debris and detergent residue.
After fine-tuning the cleaning, continue from the starting area. Wash all areas that are 12 ft. or less in height. A six ft. wand works in most cases. Use the two and four ft. wands in tight areas. Do the entire walls that are over 12 ft. high last.
Acid-based cleaners can be an effective chemical when cleaning environmental pollutants, such as carbon build up.
When cleaning masonry or concrete, use an acid-based formula only after having discussed the process with the homeowner. It is important to educate the customer on acid and its proper use, so they understand it is not dangerous to use on the home’s surface areas.
Cleaning chemicals can enhance outcomes on painted surfaces, yet employees require specific training in using acid-based detergents. Job-site supervision of employees is a must when using acid-based detergents.
To avoid chemical damage when using the two-step chemical method, start by first watering all the vegetation and glass (windows/doors) in the immediate area using a shower sprayer on a garden hose (no need to use high psi).
In an inconspicuous part of the home, test a small area beginning at the bottom of the wall and working up. Apply the acid-based cleaner to about 200 to 300 sq. ft. of surface, detailing any area that is particularly dirty.
Next, beginning at the top of the area you have pretreated, quickly spray the acid cleaner on the cleaning area. Doing this before the final rinse stops any remaining chemical reactions and leaves the surface slightly acidic. This is beneficial to homeowners planning to repaint.
Rinse slowly and thoroughly from the top down. Also rinse any non-painted surface (e.g., brick, stone) to remove any oxidation or chemical film; and then rinse vegetation again with the garden hose.
We emphasize that the cleaning area must be kept wet during the two-step process. Allowing the cleaning area to dry can damage vegetation, glass, and painted surfaces.
Wastewater containment systems are a must in many jurisdictions.
Wands should be chosen to allow team members to do the maximum amount of cleaning with their feet on the ground.
Ladders should meet all OSHA requirements for strength and valid extensions.
In the past, most estimates were done using a measuring tape or by walking the property and counting steps/strides. (The average adult man’s stride is about three ft.) Today, many estimates can be done using Zillow or Google Earth, combined with Google maps, and you may not even need to physically visit the prospective job site.
If you want to measure on site, it is recommended you abandon the old-fashioned pacing technique
and measuring tapes. Invest in a measuring wheel or laser measuring tool. Not only will you look more professional, but your measurements will be more accurate. (Be sure to accommodate any irregularities/architectural features in the exterior walls.)
Many companies have moved to more of a structured system. For example, a one-story home between 1,000 and 2,000 sq. ft. would fall into a certain price range. More structured pricing can be based on square footage of decks, fencing, and roofs. A good median price is about 20 cents per square ft.; however, you must also factor in the following as all of these considerations may add to your time and costs. Be aware
that square footage price varies throughout the market according to geographical location. Again, do your research.
Consider these factors when estimating:
Using 20 cents per sq. ft as a range and taking the average height per story (including overhangs) as 10 ft., the cost should be $1.50 to $1.75 per running/linear ft., per story.
The sides (length) of a house measure 80 ft. (80 X 2 sides = 160.)
160 linear ft. x $1.75 = $280.
Plus the front and back (width) each measure 30 linear feet. (30 X 2 = 60.)
60 x $1.75 = $105.
$280 + $105 = $385 (plus any extra decks, fencing, roof, etc.)
For split level homes, multiply by 1.5 to accommodate a story and a half. For two-story homes, multiply by 2.
Sidewalks and driveways, decks, fences, windows, and roofs are all possible value-added services/add-ons. In some parts of the country, gutters are considered a separate entity and billable ancillary to house washing. Even if the owner of a dwelling only wants the surface of the house washed, take the opportunity to mention other services during the estimating process.
The rough number can be adjusted, depending on the color of the home (light colors are less expensive to clean), amount of pollution in the area, and difficulty in accessing the house. Plan to have (and bill for) an extra person for faster completion.
When estimating, always remember that homeowners will judge your pricing on more than just dollars and cents. How soon you can start, estimated completion time, and other factors will also be considered. Never underestimate the value of your good reputation and excellent customer service!
Tools and technique: Good wash technique ensures that washed surfaces dry more evenly. Steadiness in pressure and nozzle distance keeps the amount of material (dirt and oxidized paint) removed the same. Rewash, if necessary, to eliminate severe streaking.
Lingering dirt, uneven drying, streaks on paint or gutters, or thin spots in the coating are the most significant problem areas. If dirt remains, it may be necessary to repeat the application of cleaners. Increasing the water temperature, psi, or amount of chemicals is not advised, as this can increase the risk of damage.
Streaks on paint are caused by faulty rinsing, by dirt weeping from behind the surface, or by substrate material leaching. Improper rinsing and dirt weeping are easy to resolve by extending the final rinse.
Substrate leaching is more difficult because it is usually caused by material under the painted surface breaking down chemically. To counter substrate leaching, reduce the amount of chemical or push a little more acid cleaner under the surface to stop the chemical reaction; then, extend the final rinse.
Thin coatings, a result of coating age or coating misapplication, become apparent when the paint disappears after cleaning. Cutting back on the pressure, chemicals, and/or temperature can help preserve thin coatings.
Vinyl streaking: Surfaces that are vinyl-clad, such as gutters, may yield streaking. Products made either with vinyl clad (vinyl bonded to metal) or of solid vinyl are sensitive to petrochemical pollution because the vinyl absorbs the pollutants. Clean vinyl-clad gutters by scrubbing small sections with a cleaner or washing them with hot water. An alkaline soap and rinse followed by full-pressure hot water work well.
If possible, set up a system where you can send two to three techs to a job. The lead technician ensures that processes are executed correctly and does a full walk around upon completion to ensure that tools are not left behind and everything is done as promised. Stand behind your work. Offer satisfaction guarantees and provide written estimates that outline exactly what you will be doing. In the event that something does go wrong or is missed, return to the home and take care
of whatever it is a customer isn’t happy about.
Sometimes customers have unrealistic expectations. Usually, though, any concern can be remedied with one call back. Avoid dissatisfied customers by only promising what can realistically be delivered, and put it in writing! Point out potential problem areas in advance. State your precautions/techniques/guarantees on your website, social media, etc.
Preempt complaints and difficult-to-satisfy customers by explaining as much as possible during the estimate process:
Always use your discussion time with a customer to remind the customer that trees and shrubs should be pruned regularly and not permitted to rub against the surface of the house, which can damage the exterior. Showing an interest in helping them to protect the integrity of their home demonstrates genuine concern and generates goodwill.
Donna Hillyer and Rick Hillyer, husband and wife, are the owners of Petersburg Power Washing, Inc. They specialize in commercial/residential power washing and wood restoration of decks, docks, fencing, and cedar and log homes. They are members of the PWNA. In addition to other services, they offer interior and exterior commercial/residential painting and floor coatings and cleaning of air ducts and dryer vents. Their company serves the entire Midwest, and they travel the United States to perform flatwork.