If you live in a cool climate area or your roof is shaded by trees or other structures, chances are moss, lichens, and algae will start growing on your shingles sooner or later. In addition to unsightly stains, moss and lichens retain moisture and lead to rot and mold growth, significantly shortening your roof’s lifespan. A way to keep roof vegetation under control is with copper or zinc strips. But do they work? And which should you get? Check out the key differences and find out which is best.
Zinc vs. Copper Roof Strips
The table below shows a comparison between copper and zinc roof strips:
|Characteristic||Zinc Roof Strips||Copper Roof Strips|
|Cleaning Capacity||4 to 6 inches from the strip||8 to 10 inches from the strip|
|Durability||Up to 20 years||Up to 20 years|
|Installation||Moderately difficult||Moderately easy|
1. Killing Properties
The main thing most people want to know before installing copper or zinc strips on their roofs is whether they truly work. Both copper and zinc can kill roof plant life, working in about the same way. However, copper has stronger antifungal properties compared to zinc.
What Roof Plants Do Zinc Strips Work For?
Zinc strips work against all types of roof plants, including moss, lichens, fungi, and algae. The metal also has antimicrobial properties and can fight off simple microorganisms.
In plants, the toxic effects of zinc are gradual. The metal inhibits growth and causes moss and lichens to wither. Zinc strips work faster if you’re dealing with algae or mold, the toxic metal killing these agents almost instantly.
Before installing zinc strips, it is essential to understand that they only work if it rains. Rainwater mixes with metal particles as it rolls over the strip, carrying the particles over the plant life growing on your roof. For the best results, you must consider the cleaning capacity of the strips you use and install sufficient strips for proper roof cleaning.
Do Copper Strips On Roofs Work For Roof Moss?
Copper has been used as an antifungal and antibacterial agent for ages. It is more effective than zinc in killing fungi (including mold and mildew), bacteria, and viruses. But does it work against roof plant life, too?
As a matter of fact, it does. Although copper is an essential element for normal plant growth, too much of it can inhibit plant growth and impair photosynthesis. In fact, copper is more effective than zinc when it comes to clearing moss, lichens, and algae off roofs.
Similar to zinc strips, copper strips only work if it rains. While copper has a higher cleaning capacity than zinc, you should consider the manufacturer’s recommendations regarding the strip’s cleaning capacity before deciding how many strips to install.
2. Cleaning Capacity
An important factor when trying to decide between zinc vs. copper for roof is the cleaning capacity. This refers to how many inches of plant life a strip can kill, measured from the base of the strip toward the roof base.
While the actual cleaning capacity varies from brand to brand (based on the amount of copper or zinc included in the strip alloy), copper generally has a superior cleaning capacity than zinc.
Typically, a zinc strip will clear about four to six inches of plant life. A similarly-sized copper strip can get rid of up to ten inches of roof moss and algae.
You can expect both copper and zinc roof strips to last for decades. Most manufacturers claim their strips will last for at least 20 years. Perhaps they won’t be effective for so long, but you can still expect about ten to 15 years of lifespan.
Both copper and zinc roof strips are installed in the same way. However, copper is a softer metal. Thus, it is easier to fasten under the shingles with nails.
For copper or zinc strips to be effective, you also have to install multiple rows. The second row from the top should slightly overlap with the cleaning range of the strip on top of the roof. So, if your strip has a cleaning capacity of six inches, you must install the second strip five inches under the first strip, and so on.
This is where copper gains another advantage. Because copper has a wider cleaning capacity than zinc, you can install fewer strips.
Whether you decide to use copper or zinc, you should pay particular attention to the area near the exhaust fan or bathroom vents. Installing copper or zinc around the vents can prevent roof mold and algae from getting into your house through the venting system.
Zinc strips have a clear advantage when it comes to costs. A 50-foot roll of roofing zinc strips costs between $30 and $45, on average. A 10-foot roll of copper strips costs between $40 and $60, which means you can pay anywhere between $200 and $300 for 50 feet of strips.
If you want to have the strips installed professionally, expect to pay between $550 and $950 for zinc strips, including labor and materials and depending on your roof size. Copper will cost you at least twice as much, even though it is easier to install.
Is Zinc or Copper Better For Roof Moss?
Most people choose zinc strips for roof moss and copper strips for roof algae, mistakenly believing that zinc is a better choice for general plant life, whereas copper only works on mold and bacteria.
However, as highlighted above, copper is always a better choice, regardless of the plant types growing on your roof. In addition to killing moss, lichens, algae, and fungi, copper can also get rid of bacteria and viruses which could get into your house from the roof.
Budget considerations are the only real reasons to choose zinc over copper. If you’re struggling with roof plant life but can’t spend too much, zinc is better than nothing. If you’d like to use copper but keep costs low, know that you can also use copper wire for roof moss and algae.
How to install zinc roof strips without nails?
Unfortunately, you can install roof zinc strips without nails. While you can find adhesive copper and zinc strips, they are not designed for outdoor use. Rainwater and air moisture will likely seep between the metal strip and the roof, detaching it from its place. If you’re concerned about leaks, know that you can seal the surface over the nails with roof cement.
Should I install zinc strips on the roof?
While copper is a better choice, you should definitely install zinc strips on your roof if copper is out of your budget. Zinc roof strips last for about 15 to 20 years, helping you save on professional roof cleaning costs (but only if you install the strips correctly, as explained above).
Does copper stop moss on the roof?
Yes, copper stops moss on the roof. This is why copper roofs are so expensive. However, even if you have a standard shingles roof, you can still use copper strips or wire to stop plant growth and prevent the development of mold.
Copper and zinc are both good choices for roof plant life control. Copper is more effective and easier to install than zinc. However, zinc is cheaper and lasts as long as copper does. Ultimately, choosing one over another comes down to availability, your budget, and your preference.