Is moss on a tile roof a problem, and how do you remove it?
Short answer. Moss on a tile roof is mostly a slow problem: it holds water, clogs the channels and overlaps that carry water off the tiles, and can push tiles out of position as it thickens. Remove it gently with a moss treatment and soft tools from a ladder, not a pressure washer, and do not walk on tile unless you know where to step.
Why moss matters on tile
- Blocked water channels: interlocking tiles have channels and side laps that guide water down. Moss dams them, and water can back up over the head laps onto the underlayment.
- Lifted tiles: thick clumps grow between overlapping tiles and lift them, opening gaps for wind-driven rain.
- Moisture and freeze: constant dampness stresses porous concrete and unglazed clay, and in the North Georgia mountains, freezing water in moss can chip edges.
- Clogged gutters: dislodged moss washes down and plugs gutters and downspouts.
The tile itself usually survives. The real risk is to the underlayment underneath, which is the true waterproofing layer on a tile roof.
Removing it
- Apply a moss treatment labeled for tile roofs on a dry day, protecting plants below.
- Give it time. Most products work over days or weeks as the moss dies and loosens.
- Remove dead moss with a plastic scraper or soft brush, working downhill, ideally from a ladder.
- Rinse gently with a garden hose. Skip the pressure washer, which can erode concrete tile surfaces and force water under the tiles.
- Look for cracked, slipped or missing tiles once the surface is clear.
Keeping it away
Trim branches to add sun and airflow, keep debris out of valleys, and consider zinc or copper strips near the ridge. Concrete tile can be resealed after cleaning. Insurance generally treats moss as maintenance, not a covered loss.