Cleaning a Clay Tile Roof in Los Angeles

The short answer: soft wash, minimal walking

A clay tile roof is cleaned by applying a mild cleaning solution, letting it dwell so it breaks down growth and staining, and rinsing at low pressure. Most of the work is done from ladders, the roof edge or limited safe paths, not by walking across the tiles.

High-pressure washing is a poor match for clay tile. It can chip the glaze or surface, crack older tiles, and force water up under the overlaps where it can reach the underlayment. Soft washing does the cleaning chemically and lets the rinse carry the residue away gently.

Concrete tiles shaped like Spanish clay tiles are also common in LA. The method is similar, but they can be heavier and more porous, and some have a painted color coat that wears with age. It helps to know which you have before cleaning, and an older home may have a mix of both from past repairs.

Why walking on clay tile is the biggest risk

Spanish-style barrel tiles are curved and hollow underneath. Step in the wrong spot, such as on the middle of an arch rather than where tiles overlap and are supported, and they crack. Many older tiles have become more brittle over time, and some are no longer easy to match if broken.

Wet tile is also very slippery, especially with algae on it. That is why roof cleaning on tile is planned around reach rather than foot traffic: extension wands, ladder positions at different sides of the house, and, where walking is unavoidable, stepping only on supported areas. A cracked tile may not be noticed until the first heavy rain of the season.

Lichen, algae and black streaks

Black streaks running down a roof are usually algae, often worse on shaded or north-facing slopes. Green or gray crusty patches are lichen or moss. On clay tile in LA, these tend to show in shaded parts of the roof, near trees, and on homes in canyons or near the coast where the marine layer keeps surfaces damp.

Algae streaks usually lift well with soft washing. Lichen is tougher because it roots into the surface. The solution kills it, but the dead lichen can take time to loosen and wash away with rain, and some faint marks may remain. Our black streaks on roofs guide explains this growth in more detail.

Protecting plants, gutters and walls

Roof cleaning solution runs off into gutters, down walls and onto landscaping. Before starting, plants around the house should be pre-wet and covered where needed, and rinsed again after. Downspout outlets should be watched so concentrated runoff does not collect in one bed.

Gutters often hold tile debris and organic matter, and they are worth clearing at the same visit. Paved areas below get rinsed too, and runoff should be managed, since Los Angeles Municipal Code section 64.70.02 prohibits discharging untreated wash water from paved-surface washing into the storm drain system.

What cleaning cannot fix

Cleaning will not repair cracked, slipped or missing tiles, failing mortar at ridges and hips, or worn underlayment. If water is coming in, the roof needs a roofer first. A clean roof also makes damage easier to spot, so many owners have a roof cleaned and then inspected.

Faded color is another limit. Some clay tiles are fired with color all the way through and look bright again once clean. Others had a surface coating or glaze that has weathered. Cleaning removes dirt, not wear.

When to clean and what it costs

Late summer and early fall work well in LA, ahead of the rainy season from roughly November through March, so the roof sheds water cleanly and growth has less chance to spread through the wet months. Dry, calm days also help, since Santa Ana winds can carry spray.

As of October 2026, roof soft wash on our calculator is $0.95 per square foot, with a $195 minimum per visit. Gutter cleaning is $1.25 per linear foot, and booking both takes 5% off. At Say Wash It we plan tile roofs around safe reach, and the flat price is confirmed before work begins.