Calgary roof cleaning with the no-walk soft-wash method that keeps your shingle warranty intact
Black streaks on the north slope, lichen growing under the cedar shakes, moss filling the valleys — none of it comes off with high pressure without also taking the granules with it. We use the ARMA-approved low-pressure soft-wash method, broadcast the mix from the eave, dwell, then rinse from above. Most Calgary roof jobs land between $400 and $1,200 depending on the slope, the substrate and the access.
Pressure on a Calgary roof carves the granules off — chemistry kills the algae instead
Asphalt shingle warranties from CertainTeed, Owens Corning, GAF and IKO all explicitly call out pressure washing as a damaging act. The reason is the granular surface — the coloured grit bonded to the asphalt mat is what blocks UV from cooking the asphalt itself, and a 3,000 PSI tip held at any angle strips that grit off in a single pass. The streaks come off but the roof loses years of life in the process.
Our method is the one the manufacturers point to in their own care guides. A 12V pump broadcasts a sodium hypochlorite plus surfactant mix from the eave to the ridge, the chemistry dwells for ten to fifteen minutes and kills the gloeocapsa magma (the cyanobacteria behind the streaks) plus any lichen colonies. Then a low-volume rinse comes down with gravity, gutters get flushed and the gutter line gets brightened on the same visit. Pair with gutter cleaning, house washing or soft washing on the same trip for the cleanest envelope.
Recent work
How a Calgary roof clean runs
Four steps with no technician weight on the shingles
Inspection and prep
Ladder set-up at the eave, slope and substrate confirmed, plants pre-wet, downspouts blocked at grade so the rinse residue does not foul the garden beds. Test patch if the substrate is older cedar or painted metal.
Broadcast the mix
12V pump applies the sodium hypochlorite and surfactant mix across the slope from the eave. The mix wets every algae cell and lichen colony without us setting boot on the shingles.
Dwell time
Ten to fifteen minutes for the chemistry to kill the organism and lift the colony off the substrate. Shaded north slopes get the longer dwell, south slopes the shorter one.
Rinse, gutter flush, walkaround
Low-volume rinse from the ridge down, gutter runs flushed and downspouts cleared, debris bagged and removed. Walkaround with you at the end so the result is signed off before the invoice goes out.
Calgary roof realities
Chinook freeze, north-facing algae and the asphalt shingle clock
Calgary roofs deal with three problems most exterior contractors miss. Chinook freeze-thaw cycles work moisture into the gaps under cedar shake and lift the shakes over a few seasons — a soft wash clears the moss before it gets that far. Black streaks on north-facing asphalt slopes are visible from the street and turn off prospective buyers immediately — a soft wash is the only method that gets them off without trading them for granule loss. Cedar shake roofs in the older neighbourhoods (Mount Royal, Glenmore Park, Elbow Park) are on a tighter cycle than asphalt because the wood is more porous and the moss roots deeper.
When you book the roof wash, ask about pairing with the gutter cleaning the same visit. The crew is already on the ladders, the rinse water is going to land in the troughs anyway, and the price for the second service is just labour above the equipment set-up. If a tree on the property is shedding maple keys or pine needles every fall, the gutter add-on is the difference between a clean spring and another wash next year.
Written quotesPricing
Annual + as-neededCadence
Hartford roof cleaningFinish
Pair roof cleaning with
Add-ons that make sense on the same ladder set-up
When the crew is already up on the eave, the gutter clear and a house wash are mostly extra labour above the equipment cost. Combine for the cleanest envelope and the lowest combined price.
Five questions that come up on most roof-wash quotes.
A 12V pump and a soft-wash gun let us reach the entire roof slope from a ladder at the eave or, on a single-storey, from the ground. The mix is broadcast onto the slope at low pressure, dwells for fifteen minutes and rinses with a downward-pointed wand. No technician weight on asphalt shingles, no scuffing, no displaced granules in the downspout.
No, this is the point of soft-washing. Most asphalt shingle manufacturers (CertainTeed, Owens Corning, GAF, IKO) explicitly call out pressure washing as a warranty-voiding act and explicitly approve low-pressure chemical cleaning. We follow the ARMA (Asphalt Roofing Manufacturers Association) protocol on every asphalt job so the warranty stays intact.
Every three to five years for most Calgary asphalt roofs that have visible algae or lichen. Cedar shake roofs are on a tighter cycle, every two to three years to clear moss before it lifts the shakes. Tile and metal are mostly aesthetic, every five to seven years. We will tell you straight if a roof does not yet need the wash.
Yes, with substrate-specific mix changes. Cedar shake takes a milder mix and a longer dwell because the wood is porous and acidic. Concrete tile and clay tile can handle a stronger mix on the same cycle as asphalt. Painted metal is rinsed at lower flow so the paint cannot oxidise unevenly under the chemistry. We will tell you which mix we are using before we start.
Roof wash rinse water collects in the gutters with the dead algae and lichen residue, so we flush each gutter run, clear the downspouts and brighten the outside of the troughs at the same crew visit. Adding gutter cleaning to a roof wash is the cheapest add-on because the crew is already on the ladders. Tell us when you book if you want both.
Calgary roof cleaning reviews
What homeowners say after the roof wash
★★★★★4.9· 75 reviews on Google
★★★★★
Black streaks down the north slope of our asphalt roof were two years old and the realtor said they would knock five figures off the listing price. Hartford did the soft wash from the eave, no one walked on the shingles, streaks were gone by the end of the day. House sold over ask.
G. R.
Calgary · Strathcona Park
★★★★★
Cedar shake roof on a 1968 build in Mount Royal. Moss was getting into the upper rows. The crew test-patched first, used a milder mix on the wood and rinsed from above. No shake damage, no displaced wood, moss gone and the brown back to a warmer brown.
T. C.
Calgary · Mount Royal
★★★★★
Concrete tile roof had lichen growing into the joints. We thought we would need to replace tiles. Hartford soft-washed the whole roof at a higher concentration, dwelled it long, rinsed clean. Two of the tiles I thought were ruined came back fine.
P. N.
Calgary · Aspen Woods
★★★★★
Painted metal roof on the workshop. I was nervous about chemistry near the paint. The crew explained the rinse flow before they started and the paint colour came out brighter than it had been in years. Booked them annually for the house and the shop.
F. W.
Calgary · Bearspaw
From the blog
Roof cleaning notes and substrate guides
Free written estimate
Get your Calgary roof cleaning quote in writing
Tell us the substrate, the slope and whether you are pairing the roof with gutters or a house wash. A Hartford estimator follows up within one business day with a written, itemised quote and a realistic start window. Most jobs land in the $400 to $1,200 range.
