How to Prevent Mold from Growing in Your Shed Roof

What You'll Need
Long poled scrubbing brush
Garden hose
Chlorine or oxygen bleach
Spray bottle
Zinc strips

It is easy to overlook a shed roof when it comes to outdoors maintenance. Most roofs will last a good stretch before it becomes necessary to clean thoroughly. However, should dirt and debris begin to accumulate on the roof of your shed, it is best to clean the roof soon enough. If your roof is metal, a new coat of paint or other protective finish will be necessary every 3 to 4 years. Another issue that commonly adds to shed maintenance is the growth of mold and mildew on the roof. This is common on asphalt shingles and metal roofs. Mold is usually evident as dark streaks on the surface of the roof. A shed with a roof that displays vast areas of mold detracts from the overall beauty of your home. Fortunately, you can prevent the growth of mold on the roof of your shed with the simple guide below.

Step 1 – Remove Dust and Dirt

Use a long handled broom to sweep away dust and debris from the roof surface.

Step 2 – Apply Bleach Solution

It is best to clean the roof thoroughly before you put in place some preventive measures for mold. This will give you better results. Mix a cup of chlorine or oxygen bleach with 2 cups of water in a bucket. Place the solution in a spray bottle to enable easy application on the roof. Apply onto stains and mold areas. Allow 10 minutes for the solution to act.

Step 3 – Scrub and Rinse

Use a scrubbing brush with a long pole attached to it to scrub the roof surface. Begin at the top of the roof and work your way downwards. Clean in small sections for a better result. Once you’ve cleaned the entire roof surface, rinse well with a garden hose. Allow the roof to dry well.

Step 4 – Install Zinc Strips

You can obtain these from your local hardware store. Place the strips underneath the ridge of the roof on both sides so that they stretch across the roof length. Secure the strips with a strong adhesive. Ensure that about 3 inches of the strip width is visible on both sides of the roof. This exposure is necessary to allow rainwater to act on the strips. When rain falls upon the roof, it’ll trigger the release of zinc ions. The rain water will flow down the roof with the zinc ions which inhibit the growth of mold spores and mildew. The zinc ions also prevent the occurrence of stains.


  • Eliminate as much dampness as possible around your shed. Prune trees with branches that hang close to the shed roof. Mold grows easily and quickly in environments with a heavy build-up of moisture.
  • Don’t allow dirt and debris to accumulate on your rooftop. A dirty environment is more conducive to mold growth than a clean environment.
  • It is a good idea to inspect your shed roof every 6 months. This will help to identify loose joints, missing shingles or other signs of wear and tear. Such areas allow water infiltration which encourages mold.