Tile Roof Cleaning Methods by Tile and Problem
Soft washing concrete tile
A soft wash sprays a cleaning solution, often bleach and water, through a low-pressure hose so the chemistry does the work instead of the water pressure. HomeGuide calls it the safest and most common method. The Roof Cleaning Institute of America and the Asphalt Roofing Manufacturers Association both warn against pressure washing tile because the force can damage it. Concrete tile absorbs very little water, under 1% by the Tile Roofing Industry Alliance's figure, and the alliance credits that low absorption for tile's natural resistance to mold.
Cleaning clay tile
Clay needs the same low-pressure approach and more care underfoot. A clay tile maker's cleaning advice is specific:
- Walk only on the overlap, the 2 to 3 inches where each tile laps over the one below.
- Keep high-pressure water away from laps, flashings and other spots where it can get into the roof.
- Rinse before the cleaner dries, or it leaves streaks and a sticky film that collects dirt.
- Never spray upward or under the tiles. If a spot doesn't come clean, apply more cleaner, not more pressure.
Glossy glazed clay tends to stay clean; matte and textured clay collects growth faster. Clay tile roofing covers the finishes.
Black streaks, mildew and white efflorescence
Dark streaks running down a tile roof usually mean mold or algae, and HomeGuide lists them among the signs a roof needs cleaning. A clay tile maker names shade and moisture as conditions that bring more of it. One tile maker advises trimming trees back from the house to slow mold and algae growth, and warns that heavy growth can get in the way of the roof's drainage. Not every stain is growth, though. A white, chalky film on concrete tile is usually efflorescence, salts from the cement, which the tile alliance says is harmless and washes off with rain over time. That doesn't need a chemical wash.
Clearing debris from valleys and eaves
Leaves and palm fronds on the roof are part of a cleaning visit too. A tile maker's maintenance checklist says to clear debris from rooftop gutters and header boxes, and not to wash it down with a hose, which can clog the downspouts. Valleys are delicate ground. The tile alliance says to stay off them because the cut tiles there are hard to replace, unless the tile is cut back far enough to stand on the valley metal. If the metal underneath is rusted through, that's a repair; see tile roof valley repair.
Why Pompano Beach homeowners call Pompano Tile Roofing
- Free to call, free to request a quote
- One independent local tile roofer per request, not a bidding list
- Ask for tear-off, underlayment, deck repair and permit on one written price
- Your details go only to the roofer handling your request
Tile Roof Cleaning Cost and Schedule
Cost guides price roof cleaning by area and by how dirty and steep the roof is:
| Job | Typical national range |
|---|---|
| Whole roof | about $250 to $600 (average near $440) |
| Soft wash rate, tile or shingle | about $0.15 to $0.60 per sq ft |
| Moss treatment, where moss is a problem | about $100 to $250 |
Schedule
every 1 to 3 years. Roofs under heavy tree cover may need it yearly, and HomeGuide says roofs in rainy regions need cleaning more often than roofs in sunny ones.
A tile maker also suggests a look at the roof twice a year, which pairs well with a cleaning visit. Sealing after a wash is a separate job with its own cost; see tile roof painting and sealing.
Questions to Ask Before Anyone Washes a Tile Roof
What pressure and what solution?
You want a low-pressure soft wash, not a pressure washer.Who walks the roof, and where?
On concrete tile, the tile alliance's guidance is to step on the bottom 3 inches of each tile; on clay, the overlap.Will they report broken tiles?
Ask for photos of any cracked or slipped tile they find, so a roofer can replace it before the next rain.How do they rinse?
The cleaner should come off before it dries, working down the slope.
See tile roof painting and sealing if the roof is clean but still looks faded.