While some homeowners may find moss growing on their roofs to be attractive, it is a potentially-destructive and can cause tremendous damage to a roof and its underlying structure. That is why you should take action to remove moss from your roof and treat the roof to prevent regrowth. Below is more information on why moss is destructive as well as how you can handle the problem yourself:
Why is moss destructive to roofs?
Moss is a plant, but it has a different life cycle than most plants you find in your landscape. Rather than growing from seeds, moss plants develop from spores that manage to land in the crevices on your roof. These spores are active during cooler, moist weather, resulting in a vibrant green, growing plant, but the moss will become brown during the summer months.
The most destructive problem associated with moss is its ability to retain water. Moss plants store rainwater, and this constant exposure to moisture ultimately results in a rotting roof and underlayment. This means not only shingle damage, but possible invasive harm to your home's interior structures as the water spreads.
How to remove moss - what you will need
- Floor scraping tool - purchase a tool with a long handle and blade measuring at least 12 inches wide
- Stiff-bristled broom - a push broom works best, but you can get acceptable results with a conventional floor broom provided it has sufficiently-stiff bristles
- Pump-up lawn and garden sprayer
- Liquid dish soap
- Work gloves
- Dust mask
- Roofing safety harness
How to remove moss - a step-by-step guide
1. Practice safety above all else - performing maintenance work on your roof demands your utmost attention and preparation for safety; otherwise, you could slip, fall and be injured or killed. Always wear a properly-attached safety harness that is affixed to a tie-down point on the roof. In addition, be sure your footwear is appropriate for use on a roof and is not slippery or tied loosely to your feet. Finally, be sure to wear protective gear for your eyes, hands and respiratory tract; moss spore exposure can contribute to allergies and other similar illnesses.
2. Scrape the moss away from the shingles - Once you are prepared to work, the first step is to mechanically remove moss. However, before beginning, be sure the roof is dry and the weather is relatively warm; trying to remove moss during the rain can be unsafe due to its slippery nature.
To scrape the moss off the roof, hold a 12-inch or wider floor scraping tool at a very low angle above the surface of the shingles. Push the blade into the base of the moss growth and use sharp, short strokes to chop moss away from the shingles. Just be careful to push the scraper blade downward across the tops of the shingles, and never push a scraper up toward the top of the roof. Otherwise, you may accidentally dislodge a shingle and roofing nails.
3. Sweep the roof surface - After you have removed the moss with a scraper, the next step is to remove fragments of the moss and other debris. Begin at the top of the roof, and vigorously apply a downward sweeping motion with a push broom. Again, be cautious not to push against the roof's "grain" and risk loosening shingles.
Sweep up all the debris and dispose of it in a plastic garbage bag. Keep in mind that moss can survive in harsh climates, so don't throw it out in another spot where it can establish itself and take hold of a location.
4. Spray the roof with a moss-inhibitor solution - The final step is to spray the shingles with a solution that will prevent or greatly-reduce future moss growth. Mix the solution by pouring 4 ounces of a quality liquid dish soap into an empty spray bottle, then add water to fill the bottle. Gently mix the solution to avoid creating a lot of bubbles.
Thoroughly spray the roof with the solution, and be sure to soak every area including crevices and cracks. Within a couple of days, any remaining moss will begin to brown and die off.
If you are uncomfortable performing any of these tasks, you can also contract professional residential roofers and have them remove the moss for you.