Homeowners may think moss on roofs is innocuous, just a cosmetic problem or even pretty. Yet leaving it in place can damage the roof and even have disastrous consequences. Moss is different from algae, lichen or mold fungi, which are typically easier to clean and less damaging to a roof.
Is it bad to have moss growing on your roof?
The plain and simple answer is yes. Moss can severely damage the structural integrity of any type roof. However, moss growing on your roof top is not considered lovely and should be deemed as a nemesis to your roof. Moss commonly thrives in environments that are damp and shaded.
Why does moss grow on the roof?
Moss thrives in a damp, shady environment. For this reason it often occurs on the north side of a roof—since it receives the least amount of sun—or under overhanging trees that provide shade. Over time it can cause roofing to degrade.
The less expensive solution is to spray wash the roof with a 50 percent mix of water and bleach to get rid of the algae. (No pressure washers, please. They're likely to damage the shingles.) Just be sure to wet your foundation plantings first, and rinse everything in clean water when you're done.
The plain and simple answer is yes. Moss can severely damage the structural integrity of any type roof. Moss is a simple plant that does not produce flowers and grows in blankets in natural environments. However, moss growing on your roof top is not considered lovely and should be deemed as a nemesis to your roof.
Yet leaving it in place can damage the roof and even have disastrous consequences. Moss is different from algae, lichen or mold fungi, which are typically easier to clean and less damaging to a roof. Moss readily grows on roof shingles, especially in the spaces between shingles where the spores collect.
The shingles on your roof offer an ideal environment for moss and algae to grow because it is an area of your home that is moist and humid, which when combined with the indirect sunlight of shade from trees, allows moss to thrive.
Evergreen's Moss Killer is one of the best, with the advantage that it is not at risk in a dry spell of weather. Obviously, it is best applied when the sky is dull, so it will not evaporate. Do not put it down when rain is around, as a wet day will dilute it even more.
Moss buildup can also cause more debris to be trapped on a roof, encouraging water buildup and leaks. Moss growth can also damage the asphalt shingles themselves, causing shingles to break down faster.
Wet & Forget's mixing ratio is 1 part Wet & Forget to 5 parts water. For a 1-Gallon sized garden pump sprayer, pour 20 oz (2.5 cups) of Wet & Forget into your sprayer. Next, fill the sprayer with water to the 1-Gallon marker and you're ready to go. If you have a larger sprayer you can multiply the mix.
Pour it into a pump sprayer, strap yourself into a full-body harness, tie it down and climb to the roof. Before applying the cleaner, spray the roof with water to cool it down. That'll prevent the cleaner from drying out too quickly. Then spray the cleaner onto the shingles (Photo 1).
Remove the moss and slow its recurrence.
- Shed some light on the area.
- Pressure wash the stones.
- Scrub the moss away with a scrub brush.
- Spray the pavers with a solution of equal parts water and chlorine bleach annually to help prevent the moss from returning right away.
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Mix a solution of half bleach and half water. Use a sprayer to cover the area, scrub it, then use a hose to rinse it off. Be sure to follow all directions on the container and use your protective gear. This method should keep the moss from growing back for as long as a year.
Mold and mildew are fungi that thrive in moist environments with low light levels. (And most folks can find mildew growing in their shower, too.) Algae are plants that thrive in moist environments and use sunlight for photosynthesis; they need sunlight to live.
Simply rake the yard thoroughly and with ample force to lift the moss away. Use a spring-tine rake. If you have a larger lawn, you can get a dethatching blade for your lawn mower. Set the height adjustment so that the tines can touch the surface of the soil, but if you set it too low, you will also remove your grass.
Roof shingles are a roof covering consisting of individual overlapping elements. These elements are typically flat, rectangular shapes laid in courses from the bottom edge of the roof up, with each successive course overlapping the joints below.
Shingles, or herpes zoster, occurs when the dormant chickenpox virus, varicella zoster, is reactivated in your nerve tissues. Early signs of shingles include tingling and localized pain. Most, but not all, people with shingles develop a blistering rash.
Most homes have asphalt or composite shingles. These last about 20 years, but the premium brands can go up to 50. Fiber cement will give you about 25 years. And architectural asphalt, which is thicker, holds for about 30 years, as does cedar shake.
Many DIYers include working with asphalt shingles among their abilities. Cost: A DIY asphalt roof installation on a standard ranch-style house costs from $680 to $3,700, depending on the size of the roof and the quality of the materials. Professional installation can cost between $1,700 and $8,400.
Roofs: Slate, copper and tile roofs can last more than 50 years. Homeowners with wood shake roofs should expect them to last about 30 years, while fiber cement shingles last about 25 years and asphalt shingle/composition roofs last about 20 years, the NAHB found.
Most ranch type houses in the US, measure an average of 15 to 20 squares in terms of their actual roof surface, which translates to $6,725 to $9,000 for the very basic composition shingles roof installed, based on the average installed cost of $450 per square, with a typical 5 years labor warranty.
Here are some common estimates to take into consideration for how often to replace a residential or commercial roof:
- Composition Shingles: 12-20 years.
- Asphalt Shingles: 15-30 years.
- Wood Shingles: 20-25 years.
- Rubber Roofs: 30-50 years.
- Metal Roofs: 50-75 years.
If you live in a humid area of the country, you've probably seen unsightly dark streaks on asphalt shingle roofs. Though often attributed to an accumulation of dirt, defective shingles, mold, or mildew; the most common culprit is actually a blue-green algae known as Gloeocapsa Magma that is spread by airborne spores.