Commercial building washing is not one service. Pressure washing, soft washing and hot water cleaning work by different mechanisms, run on different equipment, and carry different chemistry, and the cladding on the building decides which of the three is correct. Treating exterior cleaning as interchangeable is the most common cause of cleaning damage on a commercial facade, because a pressure that a concrete loading dock absorbs without complaint sits far above the published ceiling for brick, for fiber cement and for EIFS.
Every pressure figure in this guide is quoted from the document that published it, and every figure stays attached to the one material that document was written for. The Brick Industry Association publishes a limit for brick. James Hardie publishes one for its own fiber cement siding. Sto Corp. and Sika Corporation publish two for EIFS. The Concrete Masonry and Hardscapes Association publishes a range for interlocking concrete pavers. None of those numbers governs a material other than its own, and a contractor who quotes a single pressure for a whole building has not read any of them.
Property managers, building owners and facilities directors who can name the correct method for each cladding on their own property write better scopes and read proposals faster. Thrare Contracting sets out the method logic in full below. The commercial services overview covers what a commercial program includes and how it is scheduled, and the metro Atlanta pressure washing hub carries the substrate limits side by side in a single reference table.
What actually decides the washing method on a commercial building?
The cladding decides the method, and the square footage decides only the schedule. A 40,000 square foot warehouse wall of painted metal panel and a 4,000 square foot brick storefront are the same problem in different quantities: both are governed by what the panel finish and the mortar joint will tolerate, not by how much of it there is.
Three questions settle the method before a hose comes off the reel. First, what is the substrate, and does the body that made it publish a cleaning instruction. Second, what is actually on the surface, because biological growth, atmospheric soiling and grease each respond to a different mechanism. Third, where can the wash water legally go once the cleaning is done, because a surface that cannot be contained cannot be washed with chemistry at all.
A building rarely gives one answer. A mid-rise in metro Atlanta commonly presents brick at the base, EIFS on the upper field, aluminum coping at the parapet, glass curtain wall on two elevations, and a concrete loading dock at the rear. Five claddings mean up to five methods on one mobilization, and the scope of work should say so surface by surface.
What is pressure washing, and which commercial surfaces does it suit?
Pressure washing uses mechanical force, meaning high pressure water, as the primary cleaning mechanism. Pressure washing suits dense, non-porous, uncoated surfaces where the mechanical energy has somewhere to go: concrete flatwork, parking lots, sidewalks, loading docks, garage floors, structural steel and industrial metal decking.
Water volume matters as much as pressure, and the published documents say so directly. According to the Concrete Masonry and Hardscapes Association, in PAV-TEC-005-22, a high pressure sprayer on interlocking concrete pavement "applies cleaner and water between 1,000 and 4,000 psi (6.9 and 27.6 MPa), and at a rate between 2 and 6 gallons/minute (7.6 and 22.7 liters/minute)." The Brick Industry Association, in Technical Notes on Brick Construction 20, defines its very low pressure band as "Less than 100 psi (700 kPa); 4 to 6 gal per minute (15 to 23 L per minute)", which pairs a low pressure with a high flow deliberately.
Pressure washing is the wrong first choice wherever a coating, a soft mortar, a foam substrate or a sealed joint is carrying the surface. The failure modes are specific rather than vague: mortar joint erosion on older brick, paint and coating removal, rupture of an EIFS lamina, grain raising on wood, and water driven past a window perimeter seal into the wall assembly. The Brick Industry Association states the mechanism plainly for masonry, warning that "excessive pressure may damage brick surfaces, erode mortar joints, and remove finishes or other surface coatings, resulting in a different appearance."
Surface cleaners, meaning the rotating enclosed heads used on flatwork, belong in this method and nowhere else. A surface cleaner holds a fixed standoff and a fixed angle across a slab, which is what makes a parking deck or a dock apron come out even rather than striped. On a vertical wall the same tool cannot hold either, so a wall is worked with a fan tip and a controlled distance instead.
What is soft washing, and why does the chemistry do the work?
Soft washing uses chemistry rather than mechanical force as the primary cleaning mechanism, applying a surfactant and biocide solution at low pressure and letting the solution release biological growth and atmospheric soiling before a rinse. Sika Corporation states the principle in one line in its Senergy technical bulletin for EIFS and stucco: "The chemicals provide the cleaning, not the water pressure."
Soft washing is the correct method for EIFS and synthetic stucco, painted surfaces on any substrate, vinyl and composite siding, fiber cement siding, wood with appropriate chemistry, roofing materials, exterior insulation systems, and signage or cladding panels carrying an applied finish. Every one of those surfaces is doing its job through a coating or a laminate that mechanical force removes along with the dirt.
The application pressures that the manufacturers publish for soft washing are low by design. According to the Brick Industry Association, cleaning solution applied by sprayer to brickwork should go on at "a pressure of 30 to 50 psi (200 to 350 kPa)", and the same document warns that "No more than 50 psi (350 kPa) of pressure should be used, because higher pressure can force the cleaning solution deep into the masonry to become a source of future staining." Driving chemistry into a porous wall creates a staining problem that outlives the cleaning by years.
Rinse sequence is part of the method rather than a detail at the end. James Hardie, in Technical Bulletin #20 for its primed and ColorPlus siding, instructs that a cleaner should "clean a small section at a time. Start from the top and work your way down to prevent dripping or streaking onto the cleaned area." Sika gives the complementary instruction for stucco walls, recommending that lower elevations be kept wet "to prevent run-off from above from causing streaking."
How long does soft wash chemistry have to dwell before rinsing?
The registered product label sets the dwell time, and no trade association or manufacturer document reviewed for this page publishes a universal figure. A soft wash solution that makes a kill claim against algae, mold or mildew is an antimicrobial pesticide, and the United States Environmental Protection Agency defines antimicrobial pesticides as "substances or mixtures of substances used to destroy or suppress the growth of harmful microorganisms such as bacteria, viruses, or fungi on inanimate objects and surfaces."
That classification carries a legal consequence that most cleaning guides omit. Under 7 U.S.C. 136j(a)(2)(G), it is unlawful for any person "to use any registered pesticide in a manner inconsistent with its labeling." Dilution ratio, contact time, surface restrictions and rinse instructions are all label text, so a contractor who dwells a product for two minutes because the crew is behind schedule, or who doubles a dilution because the growth looks heavy, is not making a judgment call about cleaning. Ask a contractor which registered product is going on the building and what its label directs, and the answer separates an operator from a guesser in one sentence.
Rushing the dwell is also the most common soft washing failure on a commercial facade. Rinsing before the solution has finished leaves living organisms on the surface, and a partially killed biological film returns faster than an untreated one because the competing growth around it has gone. A facade that looks clean at handover and dark again in five months was usually rinsed early rather than treated with the wrong chemistry.
When is hot water or steam correct, and when is heat prohibited outright?
Hot water and steam cleaning use thermal energy as the primary mechanism, and heat earns its place on one contamination type above all others: grease. Heat breaks the bond between a fatty soil and a porous surface in a way that neither pressure alone nor a surfactant alone achieves, which is why kitchen exhaust surrounds, dumpster pads, drive-through lanes, grease trap aprons and dock aprons at food service buildings are the standing applications.
Heat is prohibited outright on at least one common commercial cladding, and the manufacturer says why. Sto Corp. instructs users of its EIFS not to "use steam cleaning or other high temperature cleaning methods, since the EPS insulation board in the EIFS has a service temperature limit of about 165 deg F (74 deg C)." An EIFS wall is a foam board behind a thin lamina, so a method that is merely aggressive on brick is destructive here.
Discharge temperature is a second constraint on hot water, and a published one. Gwinnett County's surface cleaning guideline WQ-1, dated 04/05/2007, lists sanitary sewer discharge standards administered by the county Department of Public Utilities that include a temperature "less than 150 degrees F", a pH between 5.5 and 10.5, and oils and grease under 200 mg/L, and the guideline states expressly that the list is not a complete list. A crew running water hot enough to strip grease has to let the recovered water cool or treat it before it goes anywhere, and that step belongs in the schedule rather than in a surprise at the end of the day.
Hot water cleaning covers ground slowly compared with a cold water surface cleaner, so heat is specified as a targeted treatment for defined grease areas rather than as the method for a whole facade. A scope that calls for hot water across 60,000 square feet of precast is usually a scope that has not been priced against the clock.
What cleaning pressure does each cladding document actually publish?
Four bodies publish figures that reach the claddings on a typical commercial building, and the spread between them runs from 400 psi to 4,000 psi. Each figure below is quoted from its own document and applies to its own material only. The pressure washing hub page sets the same figures out as a comparison table for a buyer who wants them side by side.
Brick and mortar
The Brick Industry Association, in Technical Notes on Brick Construction 20, "Cleaning Brickwork", August 2018 edition, states: "Do not use water pressures higher than 400 psi (2800 kPa) as measured at the nozzle tip unless permitted by brick manufacturer". The same document classes anything above 800 psi as high pressure and states that "High-pressure water cleaning is not appropriate for brick and may damage the brickwork."
Technique is published alongside the number. The association directs a cleaner to "Use a stainless steel 25 to 50 deg. fan tip, held a minimum of 12 in. (305 mm) from the brick surface", and to "Perform trial cleaning on a 20 sq ft (2 m2) sample area and allow wall to dry before evaluating results". A trial area is the single cheapest control on a masonry job, because a wall that dries wrong on 20 square feet is a conversation and a wall that dries wrong on an elevation is a claim.
EIFS and synthetic stucco
Two manufacturers publish EIFS limits and they agree on the ceiling. Sto Corp., in its StoTherm EIFS repair and maintenance guide, document S707B, states: "If a pressure washer is used, keep the pressure at approximately 200-500 psi (1.4-3.4 MPa), and keep the nozzle several feet from the surface. Do not exceed 500 psi (1.4 MPa) pressure, as the EIFS surface integrity can be destroyed with higher pressure washing." Sto's own guide prints two different metric conversions for that 500 psi figure, so the psi value is the one to work from.
Sika Corporation, in the Senergy technical bulletin, sets the same ceiling with a standoff attached: "Never use water pressure more than 500 psi or allow pressure nozzles to come within 2 feet of the wall. Excessive pressure may damage textured finishes and EIFS lamina. Use fan type tips (30-45 deg. or greater) on the pressure washer." Sika adds that frequent power washing "may result in premature deterioration of the Senergy finish", which is an argument for a soft wash program rather than an annual blast.
Before any wet work on EIFS, a contractor should walk the elevation for cracks, delamination and failed sealant joints. Water that gets behind an EIFS lamina stays in the foam, and a moisture problem inside the assembly costs a multiple of the cleaning. Compromised joints are repaired first, on a separate scope, and the wash follows.
Fiber cement siding
James Hardie Building Products, in Technical Bulletin #20 covering its primed and ColorPlus Technology siding, states that "Low pressure water spray, a soft bristle (nonmetal) brush is most suitable for cleaning fiber cement products", and that "Using wide fan tips that are kept a minimum of 6 feet from the wall and at pressures under 1500 psi will minimize the chance of damaging the siding." The same bulletin lists sand blasting and acid washing as not recommended, and warns that damage from improper cleaning or maintenance "may not be covered by the James Hardie warranty."
Two qualifications belong with that figure. The 1500 psi ceiling is a manufacturer instruction for the manufacturer's own product, not a standard for fiber cement as a category, and the 6 foot standoff travels with the number rather than being optional beside it. A crew working at 1400 psi from 18 inches has met neither half of the instruction.
Interlocking concrete pavers and hardscape
The Concrete Masonry and Hardscapes Association, in PAV-TEC-005-22, publishes the widest range of the four, at "between 1,000 and 4,000 psi" with flow "between 2 and 6 gallons/minute", and pairs it with a nozzle instruction: "A nozzle that creates a wide spray enables a large area to be covered efficiently and prevents sand from being washed from the joints." The association adds that "A low angle of attack from a wide nozzle spray will also reduce the risk of dislodging joint sand."
Efflorescence on pavers is a chemistry problem rather than a pressure problem, and the same document treats it that way, directing that "Cleaners to remove efflorescence are applied with a low pressure pump spray 30 to 100 psi (0.2 to 0.7 MPa)." Joint sand replacement after a hardscape clean is a line item, because a paver field washed at the top of that pressure range gives sand back whether the scope mentions it or not.
Glass curtain wall, precast concrete and metal panel
Glass curtain wall, precast concrete panel and painted or PVDF-coated metal panel are the three common commercial claddings for which this guide found no trade association or manufacturer pressure limit to quote. What can be said without inventing a number is the mechanism. A curtain wall is a system of glass, aluminum framing and silicone glazing seals, so water driven at a perimeter seal is water pushed into the wall assembly, and a low pressure rinse with glass chemistry, or a pure water pole system carrying deionized water to a brush head, cleans the glass without loading the seals. Precast panels carry efflorescence and carbonation soiling that respond to chemistry applied before any rinse, not to a higher pressure. Coated metal panel takes a pH-neutral or mildly alkaline detergent, because an aggressive alkaline cleaner alters a factory finish permanently and no repaint is a warranty repair.
Which surfaces have no published cleaning pressure at all?
Most of them, and a contractor who supplies a confident number for every cladding on a building is supplying invention rather than instruction. Published cleaning limits exist where a trade association or a manufacturer chose to write one, which in practice means brick, fiber cement, EIFS and interlocking pavers.
Where no published figure exists, the correct answer is procedural rather than numeric. The panel or coating manufacturer is asked for its own cleaning instruction, because a finish warranty is written by the same company. A trial area is cleaned and allowed to dry before the elevation is committed, which is the control the Brick Industry Association writes into its own procedure. The gentlest method that will do the work is tried first, and pressure goes up only if chemistry and dwell have already failed. Absence of a number is not permission to pick one.
Where does the wash water go, and why is that part of the method?
Wash water disposal is half of method selection, because a surface that cannot be contained cannot be cleaned with chemistry. Under 40 CFR 122.26(b)(2), an illicit discharge is "any discharge to a municipal separate storm sewer that is not composed entirely of storm water except discharges pursuant to a NPDES permit (other than the NPDES permit for discharges from the municipal separate storm sewer) and discharges resulting from fire fighting activities." Exterior wash water carrying detergent, sediment or oil is not composed entirely of storm water, so containment is the compliance path on a commercial site and the permit question never opens.
Local instruments say the same thing in local language. Inside the City of Atlanta limits, section 74-436 of the Atlanta City Code states that "No person shall throw, drain, or otherwise discharge, cause, or allow others under its control to throw, drain, or otherwise discharge into the storm sewer system of the City of Atlanta any pollutants or waters containing any pollutants, other than stormwater", and the city's definition of a pollutant expressly includes "detergents (biodegradable or otherwise)". The pressure washing hub covers which jurisdiction's ordinance reaches a given metro Atlanta address, because a county ordinance and a city ordinance are different instruments and only one of them governs any particular building.
Gwinnett County publishes the most detailed public method document in the region, and the sequence in it is worth knowing whatever county a building sits in. Guideline WQ-1 requires dry cleaning first: absorbents on oil and fuel, sweeping or vacuuming of powders and loose dirt, collection of litter and animal waste, and mopping of liquid contaminants, all before water touches the surface. Section 3.1(2) of the guideline states that, outside one narrowly defined exception, "washwater generated during surface cleaning must never be allowed to enter into a storm drain." Section 3.1(5) rules out evaporation as a disposal method, and section 3.1(11) states that "As the generator of the washwater the surface cleaner is considered jointly responsible with the property owner for its appropriate disposal."
One sentence in that guideline should end a common sales conversation. Section 3.1(10) states, in capitals in the original: "There are NO 'environmentally friendly' or 'biodegradable' cleaning products that are approved for discharge to storm drains." A contractor who answers a containment question by naming a green product has answered a different question, because the product's biodegradability does not authorize the discharge.
Gwinnett's guideline implements the county's Illicit Discharge and Illegal Connection ordinance, and that ordinance carries its own penalty. Section 100-27(f) of the Gwinnett County Code provides that "Upon conviction, such person shall be punished by a fine not to exceed $1,000.00 or imprisonment for 60 days or both. Each act of violation and each day upon which any violation shall occur shall constitute a separate offense." Two limits belong with that figure. Section 100-21(e) of the same article states that "The provisions of this article shall apply throughout the unincorporated area of the county", so the ordinance does not reach an address inside Lawrenceville, Duluth, Snellville, Norcross or any other incorporated Gwinnett city, each of which runs its own instrument. And the fine is Gwinnett's, not a federal number, so it must never be repeated as a Clean Water Act penalty or carried into Fulton, Cobb or DeKalb.
What rules apply once building washing goes above the ground floor?
Fall protection rules apply, and the threshold depends on how the work is classed. The Occupational Safety and Health Administration, at 29 CFR 1910.28(b)(1)(i), requires an employer in general industry to ensure that each employee "on a walking-working surface with an unprotected side or edge that is 4 feet (1.2 m) or more above a lower level is protected from falling" by a guardrail system, a safety net system or a personal fall protection system. In construction, 29 CFR 1926.501(b)(1) sets the same requirement at "6 feet (1.8 m) or more above a lower level."
One exclusion is worth stating precisely, because it is the one most often quoted wrongly. 29 CFR 1910.28, paragraph (a)(2)(i), states that the section "does not apply: To portable ladders." Ladder work on a low commercial elevation is therefore not covered by the 4 foot rule, which is a reason to specify the access method in the scope rather than to assume a number covers it.
Access equipment for facade work above the ground floor falls into four classes, and the site conditions usually choose between them before the budget does.
- Boom lifts, articulated and telescopic: ground-based self-propelled platforms, suited to campuses and business parks with stable ground and room to set up. Urban infill sites with no ground clearance rule them out.
- Spider lifts: compact track-mounted platforms on outriggers that reach confined courtyards and tight setbacks. Mobilization costs more than a standard boom lift and buys access nothing else reaches.
- Reach-and-wash pole systems: extendable poles feeding purified water to a brush head from the ground, suited to glass and light facade work with no lift on site and no operator aloft.
- Rope access: technicians descending from the roof on rope systems, used where no lift can reach the elevation. Rope access technicians hold certification from IRATA or SPRAT, and a buyer should ask to see it.
Work that occupies a public sidewalk or lane brings a permit question with it, and the permitting authority is the jurisdiction rather than the contractor. Thrare Contracting confirms the right of way requirement with the city before scheduling any facade work that stages off a public sidewalk, and pedestrian protection goes in the plan at the same time.
What is in the price of a commercial building wash, and what is not?
A commercial building wash is priced on four drivers, and a proposal that hides any of them is a proposal that will change on site. The four are the number of distinct methods the building requires, the access class needed to reach each elevation, the containment and recovery burden imposed by the surface and the site, and the condition of the substrate before work starts.
Included in a Thrare Contracting building wash scope: a facade walk that names the cladding and the method for each elevation, the trial area on any masonry or coated surface, method-matched chemistry and dwell per the product label, wash water containment appropriate to the site, and a written scope of work stating which method applies where. Access equipment is included where the scope calls for it and named in the proposal by class, because a spider lift and a boom lift are different mobilizations.
Not included, and quoted separately when a building needs them: sealant and caulk joint repair identified during the pre-wash walk, EIFS lamina or brick repointing repair, coating or repaint work following a finish failure that predates the wash, joint sand replacement on a paver field, interior water damage remediation, and any off-site wash water disposal that a jurisdiction requires beyond on-site containment. Repair work found during a wash is reported with photographs and priced as its own scope rather than absorbed quietly into the cleaning.
Two things that raise a price and should be said out loud rather than discovered: a facade that has been washed before at the wrong pressure often needs a gentler method and more passes than an untouched one, and a building with no accessible hose bib or no place to stage recovery adds water logistics to every day of the job.
What does Thrare Contracting need from a building before the crew mobilizes?
Five items, and four of them take a property manager under ten minutes.
- The cladding types by elevation, or permission to walk the building and record them.
- Water access and the location of usable hose bibs, plus electrical access where a heated unit is in scope.
- Storm drain and catch basin locations on the property, and any known connection to a sanitary sewer that a discharge could legitimately use.
- Known problem areas: failed sealant, past water intrusion, previous cleaning damage, or an elevation the building has been told not to pressure wash.
- The access and hours constraint, meaning tenant hours, loading dock schedules, and any area that cannot be out of service during business hours.
Thrare Contracting issues a certificate of insurance to a named holder on request, and supplies its federal registration identifiers for vendor onboarding: UEI Z4WKS4UE8NJ6 and CAGE 9JAV8. Rare Earth Ltd, doing business as Thrare Contracting, is registered in SAM and holds DBE, ACDBE, MBE and SDB certifications, and participates in E-Verify.
How should a buyer test whether a contractor knows the method?
Ask for the method and the chemistry for each cladding on the building, one elevation at a time. A contractor who proposes the same pressure for EIFS, brick and glass curtain wall has answered the question, just not the way the answer was intended. A contractor who names the cladding, names the document behind the limit, and offers a trial area is describing work that can be checked.
Gwinnett County publishes consumer guidance on exactly this screening question and states the equipment problem bluntly: "The management of polluted wash water often requires the use of specialized equipment. Not all contractors have this equipment and may not be able to comply with the law." The same brochure warns the buyer about their own exposure, stating "Keep in mind that as the consumer, you may also be held responsible for illegal discharges that occur on your property." A property owner who accepts the lowest bid without asking the containment question has taken on part of the risk that the bid discounted.
Four questions worth asking before an award: which cladding gets which method and why, what registered product goes on the building and what its label directs for dwell, how wash water is contained and where it is disposed, and what access class is priced for each elevation. Answers to those four separate a contractor who has read the documents from one who has read a competitor's website.
What does Thrare Contracting clean, and how is the method set?
Thrare Contracting provides commercial building washing services in Atlanta with the method selected per facade type and per contamination condition rather than per building. Thrare Contracting runs both pressure washing and soft washing, specifies heat where grease is the contamination rather than as a default, and works to the published manufacturer and trade association limits quoted throughout this page.
Thrare Contracting serves commercial buildings across metro Atlanta: office, retail, industrial, multifamily and institutional. An estimate includes a facade assessment and a written scope of work naming the method for each surface type. Call (678) 748-3578 or email admin@thrarecontracting.com to schedule a building assessment. Related scopes sit on the commercial services page and the exterior cleaning page.
Method selection quick reference
- Brick and mortar: no more than 400 psi at the nozzle tip, 25 to 50 degree stainless fan tip, 12 inch minimum standoff, trial area first (Brick Industry Association).
- EIFS and synthetic stucco: 200 to 500 psi working range, 500 psi ceiling, nozzle no closer than 2 feet, fan tips of 30 to 45 degrees or greater, no steam (Sto Corp. and Sika Corporation).
- Fiber cement siding: under 1500 psi, wide fan tip, 6 foot minimum standoff, no sand blasting, no acid washing (James Hardie).
- Interlocking concrete pavers: 1,000 to 4,000 psi at 2 to 6 gallons per minute, wide nozzle, low angle of attack, efflorescence cleaner applied at 30 to 100 psi (Concrete Masonry and Hardscapes Association).
- Glass curtain wall, precast, coated metal panel: no published limit located; low pressure rinse or pure water pole system on glass, chemistry before rinse on precast, pH-neutral detergent on coated metal, and the panel manufacturer asked for its own instruction.
- Grease areas: heat as the primary mechanism, targeted rather than facade-wide, with recovered water managed against the receiving standard.