Roof cleaning in Sarasota should always be done by soft wash, never high pressure. The black streaks on Florida roofs are Gloeocapsa magma, a hardy algae, not dirt. A sodium hypochlorite based solution with surfactant is applied at low pressure, allowed to dwell so it kills the algae at the root, then rinsed. Call 941-266-5284.
If your roof has dark streaks running down from the ridge, you are not looking at dirt and you are not looking at a stain that will rinse off. You are looking at a living colony. It grows, it spreads, and every year it covers a little more of the roof than it did the year before.
A paver field is only as flat as the base under it. Many older Sarasota installs were screeded on shell-based sand, which is common in this part of the county and does not lock up the way washed concrete sand does. Add fifteen summers of afternoon storms pushing water toward the low side of the drive, and the edge course starts to migrate. You get a soft shoulder, then a dip.
The city is not one kind of house. West of the Trail you have older waterfront lots with mature canopy and salt in the air. The midcentury neighborhoods off Bee Ridge and Webber were built on former groves in the 1950s and 60s. East of I-75 the installs are newer, tighter, and usually under an HOA. Each of those needs a different call on cleaning pressure, joint sand and finish.
What makes Sarasota different?
Almost every lanai we clean in Sarasota has some degree of black algae or mildew in it, and it is not a cleanliness problem. A screen cage cuts direct sun by a large margin, so the pavers under it stay damp for hours after the surrounding deck has dried. Organic growth follows moisture. In heavy shade under an oak it gets worse.
Pressure alone does not solve it. Algae puts roots into the pores of the paver, so blasting the surface removes the color and leaves the organism. We treat first, let the treatment work, then clean, then re-sand. Sealing after that locks the joint and slows regrowth, which is the part homeowners actually notice. A sealed lanai in Sarasota stays clean far longer between services than an unsealed one.
What we see on Sarasota properties
- Shell-based screed sand shows up constantly in Sarasota installs from the 1970s through the 1990s and behaves differently under re-sanding than modern washed sand.
- Neighborhoods west of the Trail get measurable salt carry off the bay, which shortens sealer life compared with the same house five miles inland.
- Oak canopy over Southgate, Arlington Park and the older Bee Ridge streets keeps pavers damp and makes algae the leading complaint, not fading.
- Homes east of I-75 are usually newer and under an HOA, so finish and color approval can matter before we start.
What are the black streaks on my Florida roof?
They are almost always Gloeocapsa magma, a cyanobacteria that behaves like algae and thrives in warm, humid climates. It feeds on moisture and on the limestone filler used in asphalt shingles, which is why it is so common on shingle roofs and why it tends to run downward in streaks. It spreads by airborne spores, which is why one house on a street getting it is often followed by the neighbors.
The organism protects itself with a dark pigmented sheath, and that sheath is what you see as black staining. It is a survival adaptation against UV. It also means the discoloration is structural to the organism, not a film sitting on top, which is why scrubbing and rinsing does not resolve it.
You may also have lichen and moss, particularly on the shaded north face and under tree cover. Lichen is the more stubborn of the two because it anchors into the surface with root like structures. Moss holds moisture against the roof, which is the real problem, not just the appearance.
Why should a roof never be pressure washed?
On an asphalt shingle roof, high pressure strips the ceramic granules off the surface. Those granules are the shingle's UV protection and its wear layer. Once they are gone the asphalt underneath is exposed to Florida sun and the shingle ages quickly. You often cannot see the damage from the ground on the day it happens. You see it two or three years later as premature failure.
On barrel tile and flat concrete tile, high pressure cracks and chips tile, and worse, it drives water sideways under the tile and into the underlayment. The underlayment is what actually keeps water out of your house. Tile is a shell over it. Forcing water under that shell is how a cleaning turns into a leak.
There is also the simple matter of a person walking a wet roof with a pressure wand. Tile roofs are walked in specific places for a reason. The less time and force applied up there, the better the outcome.
Wet look or natural finish for a Sarasota driveway
This is the single most common question we get, and there is no universally right answer. A wet look sealer brings the color up hard and makes a driveway read as freshly done from the street. It also shows everything. Any repaired section, any replacement paver that is a slightly different dye lot, any patch, all of it stands out more under gloss.
A natural or matte finish keeps the paver looking like stone and hides variation. On older Sarasota drives where pavers have been swapped over the years, matte is usually the better choice. On a newer uniform field where the homeowner wants color depth, wet look is worth it. We bring samples and we will show you the difference on your own pavers before you decide.
How does soft washing actually work?
Soft washing is a chemical process delivered at low pressure, roughly the force of a garden hose. The cleaning solution is sodium hypochlorite based, mixed to a strength appropriate to the roof and the severity of growth, with a surfactant added.
The surfactant matters more than most homeowners realize. It reduces surface tension so the solution clings to a sloped roof instead of running straight off, and it lets the mix penetrate the algae's protective sheath rather than beading on top of it. Without surfactant you are mostly rinsing chemical into the gutters.
Then comes dwell time. The solution has to sit long enough to kill the organism at the root. Rushing this step is the most common mistake, because a roof will often look better before the algae is actually dead, and it comes back within months. After dwell, the roof is rinsed at low pressure and the dead material continues to weather off over the following weeks.
| Growth | How to recognize it | Where it starts | Response to soft wash |
|---|---|---|---|
| Gloeocapsa magma (black algae) | Dark streaks running downslope from the ridge | Anywhere, worst on shingle and shaded slopes | Lifts during the wash, results visible same day |
| Lichen | Crusty gray or green patches, often circular | North slopes and under tree canopy | Killed during the wash, releases over several weeks |
| Moss | Raised green cushions, holds water | Valleys, north slopes, under overhanging limbs | Dies and weathers off, valleys may need a second look |
| Mildew and general mold | Diffuse gray or black film, no clear pattern | Damp shaded areas and low slope sections | Removed during the wash |
| Organic debris (leaves, palm litter) | Loose accumulation in valleys and gutters | Under trees, in valleys and roof gutters | Cleared before washing, not a chemical issue |
Will my roof look clean immediately?
Mostly, yes. Black algae staining generally lifts during the wash and the difference is dramatic the same day. What does not always finish immediately is lichen. Lichen anchors into the surface and often needs the treatment plus several weeks of sun and rain to fully release and wash away.
We tell homeowners this before we start so nobody is surprised. A roof that still shows faint lichen shadows a week after cleaning is behaving normally. The organism is dead. What is left is the residue working loose.
What we do before, during and after a soft wash roof cleaning
- Walk the property and identify plants, pool, screens and anything needing protection
- Clear loose debris from valleys and gutters so solution reaches the surface
- Pre-wet all landscaping and keep it wet for the duration of the job
- Mix solution strength to the roof type and the severity of the growth
- Apply at low pressure with surfactant so the mix clings and penetrates
- Allow full dwell time rather than rinsing early for a fast visual result
- Rinse at low pressure and flush gutters and downspouts
- Rinse landscaping again and walk the property with you before we leave
How do we schedule work in Sarasota?
Sarasota Paver Sealing Pros is based in Sarasota and works across the city every week. We deep clean, re-sand and seal paver driveways, lanais, pool decks and walkways, from 1950s block homes off Bee Ridge to newer builds east of I-75. Every sealing carries a 3 year warranty. Call 941-266-5284 for a free on site estimate.
Call 941-266-5284 and we will set a time to come look at it. Estimates are free, they happen on site rather than over the phone, and there is no obligation attached. We are reachable 24 hours a day, 7 days a week.
