REMOVING ROOF MOSS There are a bunch of cleaning products you can buy to spray and forget (in fact, I think that is a brand name). The most effective method I’ve seen for cleaning algae and moss from a roof is with a 50: 50 mix of laundry-strength liquid chlorine bleach and water.
If you’re the type of person who likes to do things yourself, then try this cleaning method. It takes some time to work.
HOW TO DO IT
1. Apply the bleach mixture to the roof moss with a sprayer and allow the solution to soak in for 15 to 20 minutes.
2. Rinse thoroughly with low- pressure water.
3. You may need to reapply and leave on longer but avoid letting the solution dry completely
4. Remember to protect land- scaping below the roof runoff and to wear personal protective equip- ment when working with chlorine bleach.
5. Never use a pressure washer to clean an asphalt shingle roof as this will cause granule loss and very likely premature failure of the roof system.
In severe cases, it may take more than one bleach treatment to kill all the moss. The roof moss will loosen over time and may be removed with a leaf blower. Remember to direct the blower’s airflow down the slope to avoid driving debris under the edges of the shingles.
The same stuff that fights moss on your roof—a chlorine bleach solution—can kill mold and mildew and clean stains around the home. Shady areas of the home are most prone to infestation and should be regularly inspected. After protecting the surrounding vegetation from the bleach, the solution can be applied with a sprayer, allowed to work for about 15 minutes, then thoroughly rinsed off. One aggravation that comes with using the chlorine-water solution is that the liquid runs off when applied to vertical surfaces, when the bleach would have more effect if it maintained contact with the work surface for a few minutes.
Moldex Instant House Wash addresses the runoff problem by offering an advanced bleach gel formulated with Active Cling Technology. It allows the cleaning agents to hold onto a verti- cal surface longer to achieve the highest effective contact time. It removes tough stains from mildew, mold, algae, fungus and moss without scrubbing, and restores the original look to vinyl, brick, stone and wood siding. When connected to a standard garden hose that mixes the solution right inside the spray bottle, the nozzle stream will reach the second story of a house and cover up to 4,000 square feet per container. Whereas chlorine bleach does an excellent job of killing bacteria and viruses, and removes superficial mold, it has not been proven effective in killing mold on porous surfaces such as wood. Chlorine bleach will clean the surface of outdoor wood, but the porous nature of the woodgrain will often allow the mold to return. This is because the mold’s enzyme roots grow inside the pores, and chlorine bleach can- not penetrate the porous material due to its ionic structure. Chlorine bleach also damages the lignin in the wood, which is how the wood is bonded together, and this will make it more prone to aging and splintering along the surface. Chlorine bleach can also cause some deck stain/sealers to fail, removing the color tone and even some of the wood’s natural color.
A better alternative for deep cleaning outdoor wood is to use oxygen bleach. As found in laundry detergent, oxygen bleach cleans fabrics without disrupting the color or damaging the fibers. Oxygen bleach can usually be combined with water, applied to the wood and allowed to sit for 15-20 minutes, then it can be easily rinsed from the surface with a garden hose. Oxygen bleach can also clean the wood without harming the surrounding vegeta- tion, which eliminates the need to use plastic or drop cloths for protection.
DO IT YOURSELF
KILLING MOLD & MILDEW OUTDOORS
You can mix a 50: 50 blend of laundry-strength liquid chlorine bleach and water.
Apply the bleach spray liberally to the moss with a sprayer. Allow the solution to soak in for 15-20 minutes.