Pressure washing
Roof Washing Cost Calculator
Prices roof washing, where pressure washing asphalt shingles destroys them.
Result
A planning estimate, not a quote. Access, the age of the equipment, what is found once it is opened up and local labour rates all move the real figure, sometimes a long way.
Get a Free Business AuditHow the calculation works
Hours times crew times rate, plus chemicals and the call-out, by roof area. Roof cleaning is a soft wash and nothing else: a hypochlorite solution applied at low pressure, left to work on the algae, and rinsed or in some methods left to weather off. The labour is application, dwell and safe access rather than cleaning effort, and much of the cost reflects working at height safely rather than the chemistry.
What moves the number
- Roof area and pitch, since a steep roof changes access and safety entirely.
- Extent of algae and lichen, which affects solution strength and dwell.
- Access, including whether the work can be done from ladders or needs roof access.
- Protection for plants and surfaces beneath the runoff path.
Where this one goes wrong
Pressure washing an asphalt shingle roof removes the protective granules, which is the layer that shields the asphalt from ultraviolet light, and it shortens the roof's life significantly. It also commonly voids the manufacturer's warranty, and roofing industry guidance is consistently against it. The correct method is low pressure chemical treatment. Anyone proposing to pressure wash shingles is proposing to damage the roof. Working at height is the other serious matter: falls are among the most common causes of death in this kind of work, fall protection requirements apply, and a steep or wet roof is not a surface to improvise on. Much roof washing can be done from ladders or the ground with the right equipment, which is safer as well as faster.
Before you quote
- Never pressure wash asphalt shingles; use a low pressure chemical treatment.
- Check the roofing warranty position before any cleaning method is agreed.
- Use proper fall protection, and prefer ground or ladder application where possible.
- Protect plants and surfaces in the runoff path.
Where the rules come from
Questions
About this calculator
Can an asphalt shingle roof be pressure washed?
It should not be. High pressure strips the protective granules that shield the asphalt from ultraviolet light, which shortens the roof's life substantially, and it commonly voids the manufacturer's warranty. Roofing industry guidance is against it. The correct method is low pressure chemical treatment.
What are the black streaks on my roof?
Usually algae growth, which feeds on the limestone filler in shingles and is cosmetic rather than structural in its early stages. It responds to a hypochlorite treatment applied at low pressure and left to work. Lichen and moss are more tenacious and hold moisture against the roof.
Is roof washing dangerous?
Working at height is among the most dangerous parts of this trade, and falls are a leading cause of serious injury and death in it. Proper fall protection applies, and a wet roof is slippery. Much roof washing can be done from ladders or the ground with suitable equipment, which is safer and usually quicker.
The formula
total = hours x people x rate + parts + call-out, then sales tax
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How to use this calculator
- Hours on site (h). Enter your own figure; the page starts at 3 h.
- People needed. Enter your own figure; the page starts at 1.
- Labour rate charged ($). Enter your own figure; the page starts at $95.
- Parts and materials ($). Enter your own figure; the page starts at $35.
- Call-out or diagnostic fee ($). Enter your own figure; the page starts at $95.
- Sales tax (%). Leave at zero if you are quoting before tax.
The result updates as you type, so you can try a figure, see what it does to estimated total, and change it back. Nothing you enter is sent anywhere or saved.
A worked example
These are the figures the calculator opens with. Every number in the results column below is produced by the same calculation the page runs, so you can follow it through before putting your own figures in.
What goes in
| Input | Value |
|---|---|
| Hours on site | 3 h |
| People needed | 1 |
| Labour rate charged | $95 |
| Parts and materials | $35 |
| Call-out or diagnostic fee | $95 |
| Sales tax | 0% |
What comes out
| Result | Value |
|---|---|
| Estimated total main result | $415 |
| Labour | $285 |
| Before tax | $415 |
| Sales tax | $0 |
About $415: $285 of labour, $35 of parts and a $95 call-out.
How sensitive the answer is
Holding everything else steady and changing only labour rate charged, this is what happens to estimated total. It is worth knowing which of your inputs the answer actually hinges on, and which barely move it.
| Labour rate charged ($) | Estimated total |
|---|---|
| $48 | $274 |
| $71 | $343 |
| $95 example above | $415 |
| $143 | $559 |
| $190 | $700 |
Every other input is held at the example value while this one changes, which is not how a real job behaves. Treat it as a guide to which number matters most, not as five separate quotes.
What each figure means
- Hours on site (h)
- Measured in h, between 0 and 400, starting at 3 h.
- People needed
- A number, between 0 and 40, starting at 1.
- Labour rate charged ($)
- A money amount, starting at $95.
- Parts and materials ($)
- A money amount, starting at $35.
- Call-out or diagnostic fee ($)
- A money amount, starting at $95.
- Sales tax (%)
- Leave at zero if you are quoting before tax.
What the results tell you
| Result | What it is |
|---|---|
| Estimated total | The headline result. A money figure. |
| Labour | A money figure. |
| Before tax | A money figure. |
| Sales tax | A money figure. |
Estimating is the easy part
The jobs you never hear about cost more than the ones you mis-measure. BDEVY builds the marketing, systems and automation that bring them in.