Metal roofs are tougher than shingles in some ways — but they still grow moss and algae, and their finish still needs a careful approach.
Yes — metal roofs can and should be cleaned. In the Fraser Valley they grow algae, moss and lichen too, especially on shaded or north-facing sections and where debris collects. The difference from shingles is mostly about protecting the roof’s coating and working safely on a slick surface, which is why a low-pressure, surface-appropriate approach is used.
Metal roofing is popular across Chilliwack and the Fraser Valley because it sheds rain well and lasts a long time. That leads a lot of owners to assume it never needs cleaning. It doesn’t grow moss as readily as asphalt shingles, but it isn’t immune.
What grows on metal roofs
- Green algae staining, particularly on the shaded side
- Moss in seams, along ribs and where needles and debris collect
- Lichen spotting on older or rarely cleaned roofs
- Dirt and organic streaking below trees, vents and flashings
Debris that collects behind chimneys, in valleys and along the eaves holds moisture against the metal, and that’s usually where growth starts.
What’s different compared with shingles
The coating matters
Most metal roofs have a painted or coated finish. Aggressive pressure, abrasive scrubbing or the wrong products can scratch or dull it. Like shingle roofs, metal roofs are cleaned with a low-pressure soft-wash approach rather than blasted — see soft wash vs pressure washing for roofs for why.
Seams, fasteners and flashings
High-pressure water can be driven into laps, seams and around fasteners. A careful approach cleans the surface without forcing water where it shouldn’t go.
Safety
Wet metal is very slippery, and more so with algae on it. Metal roofs aren’t a good DIY job, especially on steeper pitches.
Do zinc strips help on metal roofs?
Preventive products are generally designed with shingle roofs in mind, and results on metal vary. Regular cleaning and keeping debris off the roof are the reliable ways to keep growth down — more on what preventive products can and can’t do in does zinc or moss killer stop roof moss?
Metal roof cleaning with Lucid
Our roof cleaning service covers metal roofing as well as asphalt shingles — every roof is assessed for material, pitch, access and buildup before treatment. If moss is the main problem, roof moss removal is the more targeted service. Text a couple of photos of the roof to 778-684-3677 for a quote.