In this video, This Old House general contractor Tom Silva explains how to remove roof moss and prevent it from coming back.
How to remove moss from a roof
- Slide a margin trowel under shingles to unstick them from the ones below.
- Slide sacrificial zinc strip underneath the loosened shingles.
- Secure the strip with roofing nails.
- Apply a dab of sealant to every nail head and run a bead of sealant under each shingle.
- Continue installing zinc strips across length of roof, end to end, leaving a 1/8 in. space between the strips.
- To kill existing moss and lichen, make a cleaning solution of equal parts bleach and water.
- Protect nearby shrubs and lawn with plastic tarps.
- Spray the cleaning solution onto the shingles using a garden sprayer.