How to Invoice After Roof Pressure Washing: The Soft Wash Bill

Short answer: How to invoice after roof pressure washing starts with a correction on the paper. The method line says soft wash at low pressure, not pressure washing, because high pressure on shingles is a warranty claim waiting to happen. Bill measured roof area rather than footprint, then separate lines for the hypochlorite mix by the gallon, plant protection and rinse-down, ladder sets per elevation, and gutter face work. Name the fade window, attach same-angle photos, collect before the ladder leaves the rack.

The customer called it roof pressure washing, the ad probably said roof pressure washing, and the invoice should not. On an asphalt roof the whole job is chemistry and dwell time, and the document you hand over has to say so — because a year from now, if a shingle manufacturer asks how that roof was cleaned, this piece of paper is the only answer anybody has. The general field list in what to include on an invoice still applies; everything below is what changes when the surface is 30 feet up and covered in something alive.

What goes on a roof soft wash invoice that a driveway invoice never needs?

Four blocks that flatwork never asks for: the method disclaimer, the plant protection, the biological explanation, and the fade window.

Block	What the roof line actually reads
Method	”Soft wash, low pressure application, no mechanical pressure applied to shingle surface”
Roof measurement	Measured roof area by plane, with the pitch and story count noted
Chemistry	Gallons of mixed solution applied, target strength, surfactant, dwell time
Growth type	Algae streaking, moss, lichen — priced differently, because they die differently
Plant protection	Pre-wet and post-rinse of beds, tarps, downspout diversion, shrub count
Access	Ladder sets per elevation, roof height, walkable or not, hose run length
Gutter faces	Exterior brightening as its own line, hand-applied, separate chemical
Condition notes	Curled or brittle shingles, exposed nail heads, missing granules, soft decking, found before work
Warranty	The term you offer, what it covers, and what voids it
Photos	Same-position before and after, timestamped, one set per plane

The condition notes line carries more weight here than on any other wash. A roof that needed cleaning has usually been wet and shaded for years, and you are the last person who touched it before whatever fails next. Photograph the brittle edges, the lifted tabs, the rusted flashing and the ridge cap before you set a foot on a ladder, and write one sentence per finding on the invoice.

Where does the square footage on the roof line come from?

Not from the footprint. A roof is a slope, and the slope is always bigger than the box it sits on. A 6/12 pitch multiplies plan area by about 1.118; a 12/12 by about 1.414. Bill from the footprint on a steep roof and you gave away close to a third of the surface you actually treated.

Measurement source	What it gets right	What it misses
Tape measure at the eaves	Plane widths, overhangs, dormer count	Nothing, if you also record pitch — slowest option
Satellite or aerial report	Overall area, plane breakdown, pitch	Recent additions, detached garages, tree cover over a rear plane
Plan area from the county record	A starting footprint	Every overhang, every pitch conversion, porches added later
Walking the ground perimeter	Real overhangs, real obstructions	Pitch, and any plane you cannot see from the yard

Whichever source you use, write the number on the invoice per plane rather than as one lump. “Main roof 1,840 ft², rear addition 420 ft², detached garage 610 ft²” survives an argument. “Roof — $795” does not, and it also makes the repeat treatment three years from now impossible to price without re-measuring.

Story count belongs on the line too, separately from area. The same 500 ft² of shingle on a walkout basement side and on a third-story dormer are not the same job, and the difference is ladder work, not chemistry.

How do I write the method line so the shingle warranty stays intact?

Spell out the pressure, or the absence of it. Technical guidance from the Asphalt Roofing Manufacturers Association on algae discoloration points at a diluted chlorine solution applied without mechanical pressure, left to dwell for a limited window, then rinsed gently — and most shingle warranties say plainly that high-pressure cleaning is not covered. Your invoice is where that distinction gets recorded.

Write the method line as a sentence, not a checkbox: solution applied through a low-pressure tip, dwell time observed, rinsed at low volume or left for natural rinse per the manufacturer’s guidance. Add the growth type, because it changes what happened on the roof:

• Algae streaking. The black running stains. Dies on contact with the mix and keeps lightening for weeks as rain carries the dead organism off.
• Moss. Rooted, holds water, and lifts shingle edges. It dies with treatment but the mat stays until it dries and weathers off. Never scraped, never blasted, and the invoice should say so.
• Lichen. Bonded into the granule surface. Often takes a second application, and the customer needs to read that on the invoice before they read it in a phone call.

That difference is also where the estimate and invoice most often diverge. A roof quoted as algae that turns out to be lichen on the north planes is a second treatment, and a second treatment is a change order written the day you discover it — not a surprise line at the bottom of the bill.

How do I price the chemistry instead of guessing at it?

Two pieces of arithmetic, and only one of them needs a chemical supplier.

The first is dilution, which is fixed math. Target strength divided by stock strength gives you the fraction of the mix that is stock solution. Hypochlorite sold at 12.5 percent, mixed to a 3 percent target, means 3 ÷ 12.5 = 0.24 — roughly one gallon of stock to a little over three gallons of water for every four gallons of finished mix. Hold that number, because it also tells you exactly how much stock a job burns.

The second is consumption, and nobody can give you that number honestly, because it depends on your tip, your growth density, and how much you re-hit. Get it yourself: mark the drum level before you start one roof of known area, mark it again when you are done, and divide. Once you know your own gallons of mix per 1,000 ft², every roof after that costs out in about fifteen seconds. Do the same for surfactant, which is usually a small fraction of the mix and a large fraction of whether the solution stays on a slope long enough to work.

Then the rest of the price in the same order every time: mix cost, crew hours times your loaded hourly cost, fuel and drive time, a share of overhead, then margin. Be careful with that last step. Adding 30 percent to a $200 cost gives $260 and a 23 percent margin, not a 30 percent one; for a true 30 percent margin, divide by 0.70 and charge $286. Published per-square-foot ranges are worth a glance as a sanity check only — regional labor, roof height, growth severity and season move them enormously, and your own cost decides.

Which site conditions on a roof job get their own line?

The ones that cost you an hour and are invisible in a photograph.

Condition	Why it is billable	How the line reads
Landscaping under every eave	Pre-wetting, tarping and post-rinsing beds is real time	Plant protection and rinse-down, by bed or by elevation
No spigot, or a dead-flow spigot	Rinse water has to be hauled or pumped	Water haul, tank fills, refill trips
Three stories, or a walkout side	Ladder sets and reach equipment	Access — ladder sets by elevation, extended hose run
Screens, skylights, solar panels	Masked or avoided, sometimes hand-detailed	Protection and detail, by unit
Gutter interiors full of grit	Different job entirely; blocks the rinse	Gutter cleanout, by linear foot
Gutter faces with oxidation stripes	Different chemical, hand-applied, slow	Gutter brightening, by linear foot
Roof directly over a pool or pond	Diversion and containment	Runoff control

Roof height is also a safety line, not just a pricing one. Fall protection duties attach to work at height, and the general industry rule at 29 CFR 1910.28 starts at four feet above a lower level, with tighter requirements the closer the work gets to a roof edge. If a job needed a harness, an anchor or a lift, that equipment and setup time is a line item, and it is one customers rarely argue with once it is named.

What do I put on the invoice about streaks that are still visible?

Say it in writing, on the invoice, before you leave. A treated roof does not look finished the way a treated driveway looks finished. The organism is dead on contact, but the black staining it left behind sheds over the following weeks of weather, and a customer who was not told that will call you on day three convinced the job failed.

One short paragraph handles it: the treatment kills the growth on application, remaining discoloration continues to fade with rain over the following weeks, and moss mats dry and release rather than disappearing at once. Then state your actual warranty term, whatever you have decided it is, in plain words: how long, what it covers, and what voids it — usually new overhanging tree growth, a neighboring roof shedding spores, or somebody else power washing it in the meantime.

That paragraph does two jobs. It sets the expectation, and it converts a vague promise into a defined obligation with an end date, which is the thing that keeps a three-year-old complaint from turning into a free re-treat.

What changed between the estimate and the invoice?

Roof work has a short, predictable list, and every item on it should have been a signed change order the moment you found it, not a surprise on the bill.

1. Lichen where algae was quoted. Second application, second chemical cost, second visit.
2. A plane nobody could see. Rear additions and low porch roofs hide from the driveway and from most aerial images.
3. Pitch steeper than the report said. Changes access, not chemistry.
4. Gutters full enough to block the rinse. Either the cleanout gets added or the rinse gets compromised, and you do not want to be the one who chose the second option silently.
5. Landscaping the estimator never walked. Twenty feet of new beds under the treated elevation is an hour of protection work.
6. A second story that turned out to be two and a half. Ladder sets multiply.

Anything on that list gets photographed, priced, and approved by text before it happens. A text message with a photo and a number, answered “yes, go ahead,” is a written change order, and it is the difference between a variance you get paid for and a discount you gave without meaning to.

How do I show the work and get paid before the ladder comes off the roof?

Shoot the photos from fixed positions. Roof photos are worthless if the before was taken from the driveway and the after from the side yard, because the customer cannot line them up and neither can you. Pick a spot per plane, mark it, and stand there twice. If you fly a drone, fly the same path both times.

Then present and collect on site, in this order: walk the customer to the photo positions, show them the pair on the phone, hand over the invoice with the measured planes and the fade paragraph on it, and take payment. A wash invoice is due on completion — there is no reason for terms on a residential roof, and the moment the trailer pulls away your collection rate starts dropping. If you do end up chasing one, the sequence in how to get clients to pay is the escalation path, but the cheapest version is not needing it.

A paid roof job produces a receipt as well as an invoice, and they are not the same document — invoice vs receipt covers why the customer needs both, especially when the roof was cleaned before a home sale and an inspector wants proof of the method used.

What should I keep once the roof invoice is paid?

Four things, and the roof job is a poor candidate for keeping them in a truck console: the invoice with the method and measurements on it, the photo set, the chemical receipts from that week, and the mileage on the drive out.

That is exactly what Keel is built to hold. It is an iOS app that runs entirely on the phone — no account, no bank connection, no cloud, nothing to log into — and its App Store privacy label reads Data Not Collected. Build the invoice with your own numbering, logo and brand color, drop the payment link on as a QR code, and hand the phone across the tailgate. The chemical supplier receipt gets photographed and read on device with Apple Intelligence, the drive to the job goes into the mileage log, and Freeboard shows what is actually yours after tax reserve and committed invoices come off. At the end of the year the whole thing exports as one file, or as an Accountant Pack of CSV plus a one-page summary PDF, and the ledger underneath is append-only and hash-chained so nothing quietly changes after the fact. The free tier is $0 with unlimited invoices, receipts and mileage; Keel Pro is a one-time $249.99 Lifetime purchase rather than a subscription. If you would rather keep paper, contractor receipt organizer covers the filing side.

Frequently asked questions

Should the invoice say pressure washing or soft washing for a roof?

Soft washing, with the pressure described. Customers search for roof pressure washing, so the ad can use that phrase, but the invoice is the record a shingle manufacturer may eventually read. Write that the solution was applied at low pressure with no mechanical pressure on the shingle surface, and note the dwell and rinse. That sentence protects both the homeowner’s warranty and you.

How do I bill roof area when I only measured the footprint?

Convert it with the pitch factor before it goes on the invoice. Roof area equals plan area including overhangs, multiplied by the factor for the slope — roughly 1.118 at 6/12 and about 1.414 at 12/12. Record the pitch and each plane separately on the line. A footprint-based number understates a steep roof badly, and the customer cannot verify a lump sum anyway.

Do I need a minimum charge on a roof wash?

Usually the roof itself clears it, but the minimum still belongs on your price list because setup and travel dominate a small job. A single detached garage roof or a low porch plane can measure under a few hundred square feet and still cost you a full mobilization. Bill the minimum service charge when the measured lines land beneath it, and show it as its own line.

What do I tell a customer who says the roof still looks streaked?

Point at the paragraph already on their invoice. Treatment kills the growth on contact; the staining it leaves sheds over the following weeks as rain works on it, and moss mats dry out before they release. Give them the fade window you wrote down and the photo pair from the fixed positions. Having said it before you left is what makes it credible after.

Can I invoice a roof wash before the work is done?

There is no reason to on a residential roof. The job runs a few hours, the customer is usually home, and payment on completion is normal in this trade. Prepayment makes sense only when you are carrying an unusual cost up front — a lift rental, out-of-area travel, or a drum bought for one specific job — and then it is billed against that cost, not as a blanket deposit.

Should the invoice list the chemical strength I used?

List the target strength and the dwell, not the supplier’s product name and pricing. The strength and dwell are the technical record that shows the method was appropriate for asphalt shingles. Your mix ratios and supplier cost are your business. Keep the supplier receipt filed against the job so the material cost is traceable at tax time without publishing it to the customer.

---

This article is general information, not professional or tax advice.