What should you do about moss on your house roof?
Short answer. Start by checking how much moss there is from the ground with binoculars and looking in the attic for damp spots, then treat it with a roof safe moss killer and remove it gently once it loosens. Finally, fix what invited it, usually shade, debris and slow drying.
Step 1: assess without climbing
- Use binoculars to see how widespread it is and whether shingle edges look lifted.
- Note which slopes have it. North facing and tree shaded slopes are typical in Georgia.
- Check gutters for clumps of moss and granules.
Step 2: look inside
In the attic, check the decking under the mossy area for dark stains, damp wood or rusty nail tips. Damage there means you need a repair, not just a cleaning.
Step 3: treat it
- Pick a product labeled for roofs and for your roofing material.
- Apply on a dry day with no rain forecast for the time the label specifies.
- Protect plants and keep runoff out of storm drains and streams.
- Do it from a ladder at the eaves or hire it out; mossy roofs are slick.
Step 4: remove it gently
After the moss dies and loosens, let rain wash it or push it off by hand or with a soft brush, working downslope. Never pressure wash or scrape against the shingle laps.
Step 5: change the conditions
- Trim overhanging limbs to bring in sun and air.
- Clear leaves and pine needles off the roof and out of valleys.
- Consider zinc or copper strips near the ridge.
More detail in moss and lichen on roofs and trees and your roof.