Your roof is designed to protect your home, but moss and algae can cause long-term damage if left unchecked. While these green and black streaks might seem like a cosmetic issue, they can trap moisture and weaken your roof over time.
At a base level, having these growths on your roof can make your home look neglected. This can in turn lower its value and reduce its curb appeal. You will first start to notice moss and algae as dark streaks on your roof. Although they may look like harmless streaks or patches, they can lead to serious long-term damage if ignored.
What Are Moss and Algae?
- Moss: A green, spongy plant that thrives in damp, shaded areas, moss can grow quickly on your roof, especially if you have overhanging trees or if the roof doesn’t get much direct sunlight.
- Algae: Often appearing as dark streaks, algae loves humid environments and can spread rapidly, especially in regions with warm, moist climates. Algae might not cause immediate damage, but it can affect the appearance of your roof, making it look aged and neglected.
Why Do You Need to Eliminate Roof Moss and Algae?
Damage To Your Roof
One of the top reasons why you should eliminate the roof moss and algae from your roof as quickly as possible is because it can cause some very serious damage to your roofing materials. Moss and algae will slowly work to break down the fibers in your shingles. This not only damages the shingles themselves, but forces the materials apart, making room for leaks to occur. Whenever this happen, you run the risk of damaging the entire structural integrity of your roof. For this reason, many homes must be prematurely replaced due to the moss and algae that was left unchecked.
Reduced Efficiency
Though fungus, mildew and algae are less damaging to your roof than moss, they can greatly reduce the efficiency of your home whenever they are not kept in check. This is because fungus will interfere with your roof’s natural ability to reflect light and heat. Whenever this happens, your home will stay hotter in the summer, resulting in higher air conditioning bills.
Traps Moisture
Moss holds moisture against your roof’s surface like a sponge, soaking up rain and dew, and keeping the roof damp even when the rest of it dries out. This constant exposure to moisture creates a perfect environment for mold and mildew to thrive, especially in shaded areas. Over time, mold can spread beneath the shingles and into the underlying wooden structures of your roof, leading to wood rot.
As the wood weakens from the rot, the structural integrity of your roof is compromised, making it more vulnerable to leaks and other damage. The weight of the moss itself can also add strain to your roof, and in freezing weather, trapped moisture can expand, causing shingles to crack or lift. If left untreated, these issues can snowball, leading to costly repairs or even the need for a full roof replacement.
Poor Curb Appeal
Dark streaks from algae or green patches of moss can make your home look less appealing. Whether you are planning to stay in your home for many years, or sell in the near future, the roof is the most visible portion of your home. Whenever your roof looks bad, your entire home looks bad. This is especially a problem if you are looking to sell your home. Whenever potential home buyers see the fungus-covered roof, it sets a bad first impression. This can discourage buyers from even considering your home.
How to Prevent Moss and Algae Growth
The good news is that there are simple steps you can take to keep your roof free of moss and algae:
- Regular Roof Inspections: Schedule periodic roof inspections, especially if you live in a damp or wooded area. Identifying moss or algae growth early can prevent more serious damage later.
- Keep Your Roof Clean: Regular roof cleanings, either by a professional or a gentle DIY method, can prevent buildup. Avoid pressure washing, as it can damage your shingles. Instead, use a soft-bristle brush or a specialized roof-cleaning solution.
- Trim Overhanging Trees: Trees can cast shadows and increase moisture on your roof. Trimming back branches allows more sunlight to reach the roof, reducing the growth of moss and algae.
- Improve Roof Ventilation: Ensure your attic is properly ventilated. Good airflow helps keep your roof dry, which reduces the conditions moss and algae need to thrive.
- Install Zinc or Copper Strips: These metal strips can be installed at the peak of your roof. When it rains, water running over the metal releases particles that help inhibit moss and algae growth.
Treatment Options: What to Do if You Already Have Moss or Algae
This moss has got to go, but it’s not as simple as spraying weed-killer. You need something that will attack the moss without pumping out toxic planting-killing chemicals down your drains or onto your trees, gardens, or lawns.
Zinc, in the form of a liquid, powder, or strip, erodes every time it rains, bringing the zinc directly into the moss or algae and killing it. Normal doses will not affect most other plants, and will never corrode any of the metal fittings or other materials on or in your roof. Zinc also is long lasting: the power, liquid, and strips last a year or more per application with some special treatments lasting years. Zinc in any of these forms can be handled safely without additional protection or gear.
Dry and Liquid Applications
Most of these zinc powders and granules can be applied dry or wet. Dry application requires you to get up on the roof. But it is easy to track where you’ve put the powder down. Many of these powders come with an optional sprayer nozzle to hook directly onto the hose. Most can be mixed and applied through traditional sprayer feeds from your local hardware store. Before you buy, make sure you know how much square footage you’re going to spray and check the bottles for the amount they will cover.
Zinc Strips and Galvanized Flashing
Zinc strips are an alternative to spraying the roof. Apply these strips just below the peak of the roof and hold in place with roofing nails or staples. These have about the same lifespan as liquids and powders, and usually cheaper in price. An alternative during roof installation or remodeling is the use of galvanized flashings, which boast a very long lifespan. While installation is more difficult, it follows the same procedures. Install below the roof cap and around exposed features like chimneys and skylights.
Protecting Your Roof for the Long Term
If you’re planning to replace your roof or install a new one, you can take additional steps to prevent moss and algae from becoming a future problem:
- Algae-Resistant Shingles: Some roofing manufacturers offer shingles with built-in algae resistance. These shingles contain copper granules that prevent the growth of algae, keeping your roof looking cleaner for longer.
- Regular Maintenance: Beyond cleaning, maintaining your roof includes checking for broken or missing shingles, ensuring proper drainage, and keeping gutters clear. This will help prevent water from pooling, reducing the chances of moss or algae taking root.
Final Thoughts
Dealing with roof moss and algae might seem like an extra chore, but the payoff is well worth it. A clean, well-maintained roof not only improves the appearance of your home but also extends its lifespan, protecting your investment in the long run. By staying on top of prevention and addressing issues early, you can save yourself from costly repairs and enjoy peace of mind knowing your roof is in great shape. If you have questions or are looking fora professional roofer to help with an ongoing or potential moss problem, our experts at Remodart can help.
