Zinc and copper strips are the most oversold product in roof moss prevention. We'll install them properly — and tell you honestly what to expect, including their real limits in our climate.
Zinc strips sit near the roof ridge. When it rains, water picks up tiny amounts of zinc and carries it down the roof slope, creating a zone where moss struggles to grow. The concept is sound — and on a clean roof, strips do slow regrowth.
Here's what most installers won't tell you: the effective range is limited — typically just a few feet below each strip. In the Pacific Northwest's aggressive moss climate, strips alone won't keep a shaded Shoreline roof clean. Professional roof cleaners in Portland and Seattle report seeing moss growing happily just feet below installed strips.
Zinc: cheaper, widely available, moderately effective. The standard choice for most homes.
Copper: more effective at killing moss, but significantly pricier. Worth considering on high-value roofs or severe shade situations.
What to avoid: face-nailing strips through shingle faces. Every nail hole is a potential leak — proper installation tucks strips under a shingle course with sealed fasteners.
We'll assess your roof and tell you what will actually work — even if the answer isn't strips.
📞 Call (206) 555-0199