Roof cleaning in Burlington is mostly a fight against two things: green moss on shaded north slopes under mature maples and oaks, and the black algae streaks that spread down sunnier faces. Working from Burlington, Fixall Roofing removes both with soft washing and low-pressure rinsing, so the roof comes back clean without losing the granules that protect it.
On this job, method matters more than muscle. Blasting a shingle roof with a pressure washer makes it look clean for a week and costs it years of service life.
Because we are roofers rather than a pressure washing company, we can tell which growth is cosmetic and which is already lifting shingles or holding water against the deck. The service suits homeowners getting ready to sell, owners in tree-covered neighbourhoods such as Roseland, Shoreacres and Tyandaga, and anyone stretching the life of a roof that still has years left.
Every roof cleaning starts with a look at the surface: material, age, slope, the type and amount of growth, and whether anything is already loose or damaged. That check decides the cleaning method, the solution strength and whether a repair should come first.
We keep pressure washing for hard surfaces that can take it, such as walkways, patios and coated metal roofs where the panel maker approves it, and even then we use moderate settings and a wide fan tip. Asphalt shingles, cedar and most flat roof membranes are soft washed.
Price depends on roof area, pitch and height, how heavy the growth is, and how much landscaping needs protecting. You receive a written price after we have seen the roof.
Cleaning pairs well with seasonal roof maintenance, since a clean roof is far easier to inspect seam by seam.
Asphalt shingles are topped with ceramic-coated mineral granules that block UV light and give the shingle its colour. A pressure washer at typical settings knocks those granules loose in patches, exposing the asphalt underneath to sun damage.
Shingle manufacturers warn against high-pressure washing, and damage it causes can fall outside the limited material warranty. Water forced uphill under the shingle laps can also soak the deck and reach the attic.
Soft washing uses a pump sprayer at garden hose pressure or lower to apply a cleaning solution. The solution kills algae, moss and lichen at the root, and a gentle rinse plus the next few rains carry the dead growth away.
For algae we mainly use sodium hypochlorite blends with a surfactant that helps the mix cling to the slope. Near sensitive plants and on wood we switch to oxygen-based cleaners such as sodium percarbonate, and every batch is mixed to the roof and the growth rather than used at full strength by default.
Not everything dark on a roof is dirt. Identifying the growth tells us how strong the treatment needs to be and how much damage has already been done.
| Growth | What it looks like | Damage it causes | Treatment |
|---|---|---|---|
| Algae (Gloeocapsa magma) | Black or dark grey streaks running down the slope | Mostly cosmetic, but darkens the roof and holds moisture | Soft wash with a hypochlorite blend |
| Moss | Green, spongy clumps along shingle edges on shaded slopes | Holds water, lifts shingles, feeds deck rot | Treat, let it die back, then remove gently |
| Lichen | Flat, crusty grey-green or yellow patches | Roots grip granules and leave pitting | Repeat treatment and time, never scraped |
| Leaf and needle debris | Piles in valleys, behind chimneys and in troughs | Traps water, blocks drainage, feeds moss | Hand removal and eavestrough flushing |
Algae spreads by airborne spores, which is why streaks often show up on one house and then on its neighbours. Shingles with copper-containing algae-resistant granules slow streaking but do little against moss or lichen on a shaded slope.
A typical house takes a crew most of a day, depending on size, pitch and how heavy the growth is. The work runs in three stages.
Before any solution goes on, we soak the gardens, shrubs and lawn below the eaves with clean water so plants take up water instead of runoff. Delicate plants are covered with breathable tarps, and cars, barbecues and patio furniture are moved or covered.
Downspouts are pointed away from beds or into a collection point, so concentrated runoff never pools in one spot. Plants and siding get a second rinse at the end of the job.
The solution goes on with a low-pressure pump, wetting the growth evenly without flooding the surface. Dwell time is usually 15 to 30 minutes for algae, and we keep the surface damp while it works.
Product choice changes with the roof: a stronger blend on shingles with heavy algae, an oxygen-based cleaner on cedar and a manufacturer-approved cleaner on painted metal. We avoid hot afternoons in direct sun, when the solution dries before it can work.
After the dwell time we rinse at low pressure and lift loose moss off by hand or with soft brushes, always working downslope so shingles are never pushed upward. Thick lichen is left to release over the following weeks rather than scraped.
Valleys, the high side of chimneys and skylight curbs are cleared of debris. We finish by flushing the eavestroughs and confirming every downspout runs freely, since cleaning sends a lot of material into them.
Zinc or copper strips fastened just below the ridge release trace metal each time it rains, which slows algae and moss on the slope beneath. They are most effective on the top few metres of the roof, so they reduce regrowth rather than prevent it entirely.
Trimming branches back from the roof lets in sun and air and cuts the supply of leaves and needles. On Burlington's older, tree-lined streets, overhanging canopy is the biggest reason roofs need cleaning more often.
When the roof is due for replacement, algae-resistant shingles are worth specifying on a shaded lot. Lines such as GAF Timberline HDZ and CertainTeed Landmark are available with copper-containing granules designed to resist streaking.
Clear eavestroughs help as well, because rotting debris at the roof edge holds moisture against the bottom courses of shingles. Properly fitted gutter guards cut down how often that debris builds up.
Metal panels from suppliers such as Ideal Roofing and Vicwest have painted finishes, often silicone-modified polyester or Kynar 500. We clean them with a mild detergent and soft brushes or a moderate rinse, checking fasteners, seams and trim as we go.
Flat roofs need drains and scuppers cleared and any growth removed gently, since EPDM, TPO and modified bitumen scuff easily. Thorough cleaning is also the first step before a roof coating, because coatings only bond to a surface free of dirt, chalking and organic growth.
Wood is the most delicate surface we clean. On cedar shake roofs we use an oxygen-based cleaner and very low pressure, because high pressure raises the grain, splinters the shakes and shortens their life.
After cleaning, cedar can be treated with a preservative to slow weathering and regrowth. Whether that is worth the cost depends on the age and condition of the shakes, and we give you a straight answer.
Pressure washing can, by stripping granules and forcing water under the shingle laps. Soft washing at low pressure with a properly mixed solution does not harm shingles, and it is the method we use on every asphalt roof.
On shaded lots with heavy tree cover, every few years is common, roughly every three to five. Open, sunny roofs may only need cleaning when streaks or moss appear, and some never do.
Yes. Moss holds water against the shingles, grows under the edges and lifts them, and in freeze-thaw weather that trapped moisture can crack shingles and rot the deck. Treating it early, before it spreads, costs far less than repairing what it leaves behind.
Send us a few photos or book an on-site look, and we will tell you what is growing on your roof, which method we recommend and what it will cost in writing. Spring and fall are the best seasons for cleaning, when mild temperatures let the solution work without drying too fast.
If cleaning uncovers loose or damaged shingles, we show you photos and quote the repair separately so the decision stays yours.
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