Professional Exterior Building Cleaning: Costs & How to Hire

Three choices shape most exterior cleaning outcomes: the method you pick, the budget you set, and the contractor you hire. Make one of those wrong and the result is a cosmetic fix at best, an expensive repair at worst. I co‑own California Glass & Solar, and in the Bay Area we’ve learned a few repeatable practices—purified‑water solar cleans, custom brushes, and containment-first work—that keep exteriors safe, warranties intact, and energy systems productive. Below is a compact, usable guide so you can decide quickly and hire confidently.

Quick decision guide: which method, what to budget, and the first steps

• Soft wash for delicate surfaces — roofs, painted siding, wood, and stucco. Low pressure plus targeted chemistry kills organic growth rather than blasting it away.

• Pressure wash for durable surfaces — concrete, brick, and heavily soiled walkways. High pressure removes stains and embedded grit efficiently.

• Require proof of insurance and a written runoff plan before work begins — containment is non‑negotiable in coastal and urban Bay Area jurisdictions.

Call a pro immediately if the job involves multi‑story access, roof work, historic or sensitive cladding, or rooftop solar arrays. For rooftop and solar work, improper technique not only risks damage but can void manufacturer warranties; those calls belong to trained crews with fall protection and purified‑water systems.

Quick price snapshot so you can decide whether to request bids: siding and concrete commonly fall between about $0.20–$0.60 per square foot; exterior windows typically $4–$8 per window; small, single‑surface jobs often start around $200–$400; larger full‑building projects commonly range $1,500–$5,000 depending on height, access, and containment. At California Glass & Solar we begin every quote with photos and a short site visit so we can size containment and match methods to materials—avoiding surprises and change orders.

Soft washing vs pressure washing: what each method does and when to use it

The fundamental distinction is force versus chemistry. Pressure washing uses high PSI to dislodge dirt, paint overspray, and concrete stains. Soft washing uses low water pressure paired with cleaning chemistry that kills mold, mildew and algae at the root so it doesn’t return within weeks. For a practical comparison of the two approaches, see a short overview of soft washing vs pressure washing.

Technically: soft wash systems typically operate under roughly 100–500 PSI and use wide‑spray nozzles to avoid surface erosion. Pressure washers used on concrete and masonry commonly range from 1,300 to 4,000+ PSI with narrow nozzles to concentrate force. The nozzle and PSI ranges are meaningful because they determine whether water strips finishes or simply rinses them. If you need professional help with low‑pressure cleaning, consider our Soft Washing Services in The Bay Area, and for hardscape restoration see our Expert Pressure Washing Services in The Bay Area.

Chemistry and safety matter. Soft washing relies on purpose‑formulated, biodegradable solutions—often sodium hypochlorite blends with surfactants and algaecides—followed by an appropriate dwell time so the active agents reach root growth before rinsing. Professionals dilute per label, protect landscaping, and neutralize runoff when required. Pressure washing usually uses plain water or mild detergents; high‑strength solvents belong only in controlled, licensed applications because they can harm plants and municipal sewers.

Material guidance by surface: asphalt shingles and historic tile roofs should be soft‑washed to avoid granule loss and water intrusion. Vinyl, painted wood, stucco, and composite siding are best treated with soft wash when algae or biological staining is present; pressure can warp or strip paint. Wood decks and hardwoods may tolerate moderate pressure if the operator adjusts PSI and follows the grain, but soft approaches are safer for aged or soft species. Brick and stone tolerate higher pressure; concrete, driveways and sidewalks often require pressure washing to remove oil, tire marks and efflorescence. Glass is a separate skill set—streak‑free detergents, water fed poles, and spot‑free rinses—never abrasive blasting; for streak‑free service see our Expert Window Cleaning in The Bay Area.

Solar‑panel best practice is clear: cleaned with purified (deionized) water and soft brushes. No high pressure. Purified water removes mineral deposits and film without leaving residues that reduce output; soft brushes avoid scratching anti‑reflective coatings. Proper cleaning improves daily yield and keeps warranty claims straightforward. At scale, gentle, regular cleans outperformed infrequent aggressive cleans in our Bay Area arrays because the panels stay micro‑clean and produce more consistently.

Often projects combine methods: soft‑wash the building envelope and roof to treat biological growth, then pressure‑wash concrete paths and loading zones. The right workflow protects vulnerable surfaces while restoring hardscape to a like‑new condition.

Pricing decoded: per square foot, per job, and how to compare quotes

Actual pricing varies by market and job complexity, but the table below captures typical ranges you should expect when shopping bids in the Bay Area.

Cost drivers to watch: height and access (lifts and scaffolding add labor and staging fees), severity of staining (heavy oil, chewing gum or rust require specialized treatment), bundling services (combining windows, gutters, roof and solar often yields a lower total), and regulatory needs (permit fees or wastewater recovery systems raise the bid). Seasonality matters: emergency or same‑week work typically costs more.

To rough‑estimate your own job: measure or approximate the area in square feet; choose the per‑sq‑ft band that fits the surface and condition; add an access surcharge for stories taller than two or if lifts are required; add a disposal/permit line for sites near storm drains or waterways. Always ask contractors for unit pricing—surface area, prep and containment, scaffolding or lift rental, waste handling and permits, labor hours, and warranty terms. Comparing quotes line‑by‑line prevents surprise markups for things like disposal manifests or last‑minute staging changes.

For current benchmark pricing and per‑square‑foot guidelines in commercial settings, see this recent industry summary of commercial cleaning rates per square foot.

Pricing red flags: vague “per job” quotes without unit breakdowns; refusal to show proof of insurance; no containment plan for washwater; excessive low bids that require cash payment only. These are common precursors to poor workmanship or environmental violations.

Regulations and runoff: staying compliant and environmentally safe

Uncontained washwater carries legal and environmental risk. The Clean Water Act, local stormwater ordinances, and the EPA’s RRP lead rules mean that contractors and property owners must prevent polluted runoff from reaching storm drains or waterways. In practice, that means capture, diversion to sanitary systems when permitted, or water reclamation systems that separate solids and treat rinse water on site. For details on the federal lead‑based paint program and RRP requirements consult the EPA’s LBP program guidance.

On day one require a written wastewater capture plan: describe how drains will be blocked, whether berms or temporary dams will be used, and how solids (paint chips, grit) will be collected. In California coastal and urban areas, many municipalities expect zero discharge to storm drains; a contractor who says “we’ll just hose it away” is a liability. For jobs disturbing pre‑1978 paint, insist on RRP compliance—plastic sheeting extending at least 10 feet from the work area, HEPA cleanup and documentation.

Containment in the field: contractors should block nearby storm drains, set up berming or vacuum recovery if water is mobile on sloped sites, protect plants with sheeting and temporary irrigation if needed, close and tape nearby vents or windows, and extend protective sheeting 10–20 feet where wind or run potential exists. Practical measures and examples for on‑site runoff control are described in industry guidance on how to include runoff abatement measures in pressure washing services. Ask for before/after photos of the containment setup; it’s an easy verification step and shows the crew takes environmental controls seriously.

Verify environmental claims by requesting permit numbers for any NPDES or local discharge authorizations, disposal manifests for hazardous waste, and photos of capture equipment in use. If a contractor cannot produce simple documentation or refuses to sign a clause stating they will comply with local stormwater rules, move on.

Avoiding damage: common failure modes and how professionals safeguard assets

Damage patterns repeat. High pressure on soft siding strips paint and embeds streaks; pressure directed under flashing can force water behind cladding and create rot or mold; aggressive wire brushes scratch glass and solar glass coatings; harsh chemicals scorch plantings and etch concrete. These are avoidable with correct technique.

Professionals safeguard assets through test patches, correct PSI and nozzle selection, and tools designed for the job. Custom soft‑wash brushes reduce agitation and follow surface contours; purified‑water rigs for solar cleaning avoid mineral streaks; scaffolded access or platform systems reduce the need to lean pressure rigs against delicate trim. A pre‑job inspection notes vulnerable areas—old sealant, loose shingles, failing caulk—and those items are flagged before significant wet work begins.

Aftercare is part of prevention. Re‑seal or re‑caulk joints where cleaning removed failing material; apply hydrophobic coatings only where appropriate to slow regrowth, and set reasonable maintenance intervals—over‑cleaning accelerates wear and can cause finish failure. We recommend routine solar cleanings in Bay Area microclimates where salt, fog, or tree pollen accumulate; for siding, annual to biennial soft washes depending on sun exposure and shade.

Bay Area example: a two‑story Victorian had paint failure after a well‑intentioned neighbor used a rental pressure washer at 3,000 PSI. The result was stripping of the topcoat and water intrusion behind the siding that required weeks of remediation. A soft‑wash approach at under 300 PSI with a biodegradable sodium hypochlorite mix would have removed algae and preserved the finish. That experience is why we test and document a small patch before proceeding.

How to vet and hire a trustworthy exterior‑cleaning team

Start with non‑negotiables. Ask for a current business license, a certificate of general liability insurance (common commercial limits are $1M per occurrence / $2M aggregate for larger commercial work), and workers’ compensation coverage. For higher‑risk or municipal contracts request proof of bonding. Request certifications—PWNA, ISSA or OSHA training records—which indicate the crew understands safety and standards.

Verify insurance by calling the carrier listed on the certificate of insurance; confirm policy numbers, effective dates and that the policy covers the scope of work. For high‑stakes jobs insist the contractor name your property as “additional insured” for the job duration. If they balk, that is a red flag.

Sample questions to ask during an estimate (say them in this order and take notes): “What method will you use for the surfaces I showed you? How will you manage runoff and protect nearby storm drains? Can you show before/after photos of similar jobs and provide references? Who supervises the crew onsite and what are your warranty terms?” A contractor who answers with specific methods, containment steps and local references is more trustworthy than one who gives generalities.

Insist the contract include scope of work with materials and methods, itemized pricing, timeline, staging requirements (where they will park or place lifts), cleanup and disposal responsibilities, and repair or warranty terms. Add a clause requiring pre‑ and post‑job photos of containment and final condition for your records. Red flags include no written estimate, cash‑only requests, vagueness about containment, and refusal to provide references or an insurance certificate.

Commercial scopes and maintenance plans for property managers

Commercial contracts need predictable outcomes. Recommended frequencies: gutters and downspouts annually or biannually; siding in shaded or coastal areas yearly to every two years; solar arrays from once a year to quarterly depending on soiling and production targets; windows quarterly to semi‑annually for high‑occupancy spaces. Bundling services—window, gutter, roof and solar maintenance—reduces admin friction and keeps asset health aligned.

SLA items to include: response time for emergency cleaning or unblockages, agreed appearance standards with photographic benchmarks, remediation steps if standards are not met, inspection notes after each service, and an explicit price‑adjustment clause tied to fuel or material indexes. For bids insist on a site walkthrough with the prospective vendor and a staging plan that addresses access, occupant notifications, signage, and safety perimeters.

Property Cleanup & Maintenance Services | The Bay Area packages window, gutter, roof and solar maintenance into a single annual plan that includes documented before/after photos and a single invoice for easier accounting. The bundle reduces surprises and centralizes warranty and environmental documentation in one place—useful for property managers juggling multiple vendors.

Final checklist, sample estimate template, and next steps

Owner’s pre‑job checklist — do these before crews arrive:

• Move potted plants and patio furniture away from the work area and cover if leaving in place.

• Close and lock reachable windows and vents; tape interior soffit vents if requested.

• Clear access paths and identify parking or staging areas for lifts.

• Photograph problem areas and note surface materials and the number of stories for estimators.

• Confirm a contact person and working phone number for the crew day‑of.

Contractor vetting checklist — request these documents before signing:

• Certificate of insurance (general liability and workers’ compensation) and bond numbers if required.

• Written containment and wastewater disposal plan (including permit numbers if applicable).

• References and before/after photos of similar work, plus a named onsite supervisor.

• Clear warranty language covering workmanship and any recommended repairs.

• Itemized estimate with unit prices for surface area, lift/scaffold, prep/containment, disposal, and labor.

Sample estimate template (use this to compare quotes)

Quick decision flow: DIY is reasonable for small, ground‑level concrete or a single patio; anything involving roofs, multiple stories, rooftop solar, or historic cladding is a hire‑a‑pro situation. When in doubt, ask for photos, a site visit and a written containment plan.

If you’re ready to hire: request at least three itemized bids, verify insurance by calling the carrier, and ask for before/after photo commitments in the contract. For Bay Area property owners who want trusted local crews, California Glass & Solar provides purified‑water solar cleaning, streak‑free window service, soft‑wash roof and siding work, gutter cleaning, humane bird deterrent options for arrays, and free on‑site estimates with custom in‑house brushes tailored to your property.

Practical wrap: choose the right method for the material, insist on containment and permits, and verify insurance. Those three rules prevent most damage and regulatory headaches. Download or print the checklists above before you call contractors; the documentation you collect up front will protect your property and make comparisons straightforward. If you’d like a free estimate in the Bay Area, we’re happy to come by, photograph the site, and outline a clear, compliant plan.