Roofs · Siding · Stucco · Soffit
Roof & Siding Softwashing
Some surfaces should never see a pressure washer. Roofs and siding get low pressure and the right solution instead — which removes black streaks, algae and mold at the source rather than blasting them off and waiting for them to come back.
Start Here
What Softwashing Actually Is
Softwashing is low-pressure cleaning that does its work with a solution instead of force. Solution goes on at roughly garden-hose pressure, dwells a few minutes while it breaks down and kills the organic growth, then gets rinsed away.
The distinction that matters is what is doing the cleaning. Pressure washing is mechanical — a fast stream of water physically knocking material off a surface. Softwashing is chemical — a solution killing the organism causing the discoloration, so the surface is never under load.
Two tools for two problems, not a gentle version of the same thing. Hard, flat surfaces like a concrete driveway or a public sidewalk can take mechanical cleaning. A roof, a wall, and anything painted cannot.
The Difference Side by Side
Mechanical
Pressure Washing
2,000–4,000PSI
- Right for concrete driveways, sidewalks, curbs and hardscape
- Removes oil, tire marks and embedded traffic film
- Fast on hard, flat, horizontal surfaces
- Strips granules from asphalt shingles
- Forces water behind siding into the wall cavity
- Removes the stain but leaves the organism alive
- Can void roofing manufacturer warranties
Chemical · Low Pressure
Softwashing
Under 100PSI — garden hose
- Right for roofs, siding, stucco, soffit and screens
- Kills algae, mold and black streaks at the root
- No mechanical load on the surface at all
- Results last years instead of months
- Safe for landscaping, plants and pets with proper prep
- Not the tool for oil stains or ground-in concrete grime
Roofs
Why Pressure Washing Ruins a Roof
The ceramic-coated granules on an asphalt shingle are not decorative — they are the shingle’s sunscreen, blocking UV from the asphalt underneath. A pressure washer strips them, and you can watch them collect at the downspout. The roof looks dramatically better that afternoon and has lost years off its service life, which is why roofing manufacturers specify low-pressure chemical cleaning and why many warranties exclude damage caused by pressure washing.
Those Black Streaks Are Alive
The dark vertical streaking on Florida roofs is not dirt. It is Gloeocapsa magma, a cyanobacteria that feeds on the limestone filler in shingles, spreads by airborne spores, and streaks downward because rain carries it down the slope. Because it is a living colony:
- Pressure washing removes the biomass and leaves the organism. The stain goes, the colony’s foothold does not, and it regrows from what survived — often within a season.
- Softwashing kills it outright. Regrowth has to start over from spores. That is the difference between a couple of years of clean roof and a few months.
Siding & Walls
Why Siding Needs the Same Restraint
Walls fail differently than roofs, but for the same reason: pressure goes somewhere you cannot see.
Vinyl Siding
Vinyl hangs loosely over a weather barrier, overlapping so rain sheets down the outside. It is not sealed and was never meant to be. Pressure aimed upward under the laps drives water behind the panels into the wall cavity, where there is no airflow to dry it — which is how you get mold inside a wall and rotted sheathing behind siding that still looks fine. Aged vinyl also goes brittle in Florida sun and cracks under a concentrated stream.
Painted Wood & Fiber Cement
Pressure strips paint — that is what pressure washers are used for during paint prep. On a wall you intend to keep, it lifts edges and forces water past caulk joints and window flashing.
Stucco
Stucco is porous and common on homes throughout Windermere and Horizon West. High pressure etches the finish, leaving permanent light patches and wand tracks, and drives water into the hairline cracks every stucco wall develops.
In every one of those cases, low pressure plus the right solution cleans the surface completely while leaving the wall assembly doing its job.
What Comes Off
Removed Safely, at the Source
Softwashing handles the growth that makes a house look tired, without touching what is under it.
Black Streaks
Gloeocapsa magma running down the roof slope — killed at the root, so it stays gone.
Algae & Green Film
The green cast on north-facing walls and shaded side yards that never fully dry out.
Mold & Mildew
Dark spotting on siding, soffit and fascia, worst where irrigation and downspouts keep things damp.
Lichen
Crusty, anchored growth on older roofs. Harder than algae, sometimes a second pass — but never pressure.
Protecting the Property
Safe for Landscaping, Plants & Pets
Being safe around plants is not a property of the solution. It is a property of the preparation — the part of the job easiest to skip and most expensive to get wrong.
Saturate First
Every bed, shrub and lawn edge in the work area gets soaked with plain water before anything else happens. A plant already full of water cannot take much else up, and anything reaching a leaf arrives diluted.
Divert & Cover
Anything sitting in a runoff path gets tarped or the runoff redirected. Point out the plants that matter to you and I plan around them before I start, not after.
Control the Application
Solution goes where it is needed at low volume and low pressure. No overspray drifting onto beds, no mist carrying across the yard on the breeze.
Rinse Everything Down
Walls and roof rinsed, then all the surrounding landscaping rinsed a second time. Pets and kids back outside once surfaces are dry.
Common Questions
Questions I Get Asked
Will softwashing damage my shingles?
No — avoiding damage is the entire reason the method exists. The ceramic-coated granules on a shingle are its UV shield, and once they are gone the asphalt underneath starts breaking down in the sun.
Softwashing applies solution at roughly garden-hose pressure, so nothing mechanical acts on the granule layer. This is why roofing manufacturers specify low-pressure chemical cleaning, and why many warranties exclude pressure washing damage.
Will the solution kill my plants?
Not with the standard precautions, which I treat as non-negotiable. Beds and foliage in the work area get saturated with plain water first, kept wet during the work, and rinsed again afterward. Pre-wetting dilutes anything that reaches a leaf and stops the plant drawing it up.
Plants sitting directly in a runoff path get tarped or diverted. If there is something you are attached to — a vegetable bed, a specimen palm — point it out before I start.
Is it safe for pets and kids?
Keep them off the treated surfaces and out of the work area while I am applying and rinsing, and back to normal once everything is rinsed down and dry. Pets are the more common concern, mostly because dogs walk through a wet area and then lick their paws. Bring water bowls and toys inside for the duration.
How is this different from just pressure washing the roof?
Pressure washing removes the visible stain and leaves the organism. Softwashing kills the organism, which is why results last years rather than months.
The black streaking is a living cyanobacteria. Blasting it off looks like a dramatic improvement on the day, while removing granules and leaving the colony’s foothold intact to regrow from.
How long do the results last?
Typically a few years on a roof, versus months for a pressure-washed one, because the growth has to re-establish from spores rather than resume from a surviving colony.
Your own timeline depends on shade and moisture. North-facing slopes and roofs under overhanging trees will show growth again sooner.
Will there be a bleach smell?
There is a noticeable chlorine smell during the work and while surfaces dry, strongest right after application. It fades as things dry and is generally gone the same day. Closing the windows on the side being worked keeps it out of the house.
Can you softwash vinyl siding without water getting inside the wall?
That is exactly what low pressure protects against. Vinyl hangs loosely over a weather barrier by design, and high pressure aimed up under the laps drives water behind the panels where it cannot dry.
Applying at low pressure and directing the spray downward with the laps means water sheets off the way rain does, which is what the wall was built for.
What about lichen? Mine looks crusty, not streaky.
Lichen is a harder problem than algae and I would rather say so upfront. It anchors physically into the surface, can leave a faint outline even after it is dead, and heavy growth sometimes needs a second treatment.
What it does not need is pressure. Scraping lichen off shingles takes the granules with it, trading a cosmetic problem for a structural one.
Keep Looking
Pressure Washing Services
Softwashing is for roofs and walls. Hard horizontal surfaces want mechanical pressure washing — and both often happen on the same visit.
Ready to Get Clean?
Book Your
Appointment
If your roof has black streaks or your siding has gone green, softwashing is the fix. Pick a time and I’ll come look at it and give you a free quote.
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Or call/text (321) 754-0997 — email andrewcrockefeller@gmail.com — or reach out on Instagram or Facebook.