Moss might seem picturesque, but it will slowly destroy your roof. It devours the nutrients from your roofing, but will also slowly force shingles apart as they root deeper and allow water to seep in. 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. You need zinc.
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 makes it 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, and 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 roofcap and around exposed features like chimneys and skylights.
If your house’s roof is in the shade, in a cool and moisture-rich environment (such as New England), you’re at risk. These treatments and installations can be dangerous to do yourself, especially with larger homes. While not dangerous in large doses, plants should be covered before initial zinc spraying. If you have questions or are looking for someone to help with an ongoing or potential moss problem, our experts at All Weather Tite can help.