Image source: Jovag Home Inspection
If you have roof stains, damages from moss or algae, or other unsightly blemishes, it could lead to roof rot and costly roof repairs. Zinc strips feature metal flashing that is designed to help reduce moss, lichen, algae, and fungus growth when it rains. While every case is different depending on the severity of growth, some roofers contend zinc strips' effectiveness. How exactly do they work, and are they worth buying? Let's find out.
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What are zinc strips?
Image source: American ProTech
Zinc strips are 50-foot rolls of metal flashing installed under the ridge cap of your roof with galvanized roofing nails. When it rains, the zinc strips will oxidize and flow down your roof with the rainwater, helping prevent moss growth within a 6-inch radius. If your roof extends past 14 feet or so, installing a second strip is recommended.
While zinc strips will become less effective over time, some zinc flashing can last up to 20 years or more. Keep in mind that zinc strips work best before moss and fungal growth is well developed.
Pros and cons of zinc roof strips
Cheap - 50-foot rolls tend to cost about $40 at most big retail stores like Lowes and Wal-Mart, making them a great value for any homeowner on a tight budget.
Easy to install - Installing zinc strips yourself is DIY-friendly if you're not afraid to get up on top of the roof. You'll just need to perform a thorough roof cleaning with a bleach solution to get rid of any existing moss or mildew. Then, you can start nailing in the strips underneath the roof shingles on the roof ridge.
Versatile - Zinc strips can be installed on virtually any type of roofing material from asphalt shingles to cedar shake roofs and tile roofs.
Effectiveness - Some roofers contend whether or not zinc strips are an effective roof moss killer, but can help as a preventer if you install a second strip lower down the side of the roof.
Varying lifespans - Some homeowners claim zinc strips are only effective between 1-4 years, but some brands like Z-stop can last up to 20 years or more and be attached anywhere on the roof below dormers and chimneys.
Zinc vs. copper roof flashing
Image source: Basic Copper
If you’re skeptical about the lifespan or effectiveness of zinc strips, copper is another option for moss control and prevention. Here’s how they stack up.
Zinc - Zinc typically costs around $40 per 50-foot roll.
Copper - Copper is significantly more expensive, costing up to $75 per 20-foot roll.
Our verdict: Zinc
Copper - While copper strips are more expensive, they can be twice as effective as strips of zinc at controlling the growth of moss. Because copper is antimicrobial, it's able to prevent the growth of mold, algae, and moss. In addition to having a more appealing appearance, copper strips can kill up to 10 inches of moss.
Zinc - While zinc is effective at controlling most moss problems, it only affects moss within a 6-inch radius and may not last as long as copper.
Our verdict: Copper
Copper - Copper and zinc are both non-corrosive, recyclable materials but can also cause harm to farmlands and livestock because it doesn't break down as easily as other materials. While most copper levels in the air and soil typically don't pose any major health concerns, they can be harmful to your yard.
Zinc - While both copper and zinc are considered green, sustainable materials, high exposure to them can be hazardous. If you do choose to install zinc strips, you should be aware that runoff can be harmful if your gutters are full and it comes into contact with any plants or lawns.
Our verdict: Copper
Are zinc strips worth buying?
If you’re on a tight budget and want to get your moss problem under control, zinc strips are a solid option. If you don’t mind spending a little more, copper strips are more aesthetically pleasing and more effective than pure zinc. With either choice, you’ll still have to perform routine maintenance of cleaning and scrubbing your roof with bleach and cleaning solutions.