Handyman Steve Maxwell helps readers tackle common around-the-house issues, focusing this week on roof and deck duties. Lichen growth can shorten the lifespan of most roofs, but it can be removed and prevented. Cleaning a cedar roof requires special care due to the softness of cedar.
Removing Lichen from Cedar Shake Roofs
A recent widow from Vancouver Island sought advice on removing lichen from her cedar shake roof. The roof is over 10 years old but only began growing lichen last year. Here is a step-by-step procedure recommended by Maxwell:
- Have the roof sprayed with an oxygen bleach solution or a product designed to kill rooftop growths. Ensure it is non-toxic to plants, people, and animals but effective against lichen.
- Let the solution sit for about half an hour, ideally on a cloudy, cool day to prevent rapid drying.
- Lightly brush the roof downwards using a long-handled nylon brush. Avoid scrubbing upwards on the slope.
- Rinse the roof thoroughly with clear water.
- Repeat the process if any lichen remains.
- Install copper or zinc strips under the cap shingles at the peak, exposing one to two inches of metal, and every 15 feet down the slope. This releases dissolved metal that prevents future moss and lichen growth.
Hiring the Right Person
Finding the right professional is crucial. Roofing contractors often focus on replacements rather than delicate cleaning. An experienced handyman is a better option, as they can follow your directions and adapt as needed. Handymen typically charge by the hour, providing transparency. Large quotes between $7,500 and $15,000 are excessive. For a typical house, expect three to five days of work at $40 per hour, totaling $960 to $1,600.
When hiring, check at least three references and ensure the handyman has roof experience. Soft-soled shoes are essential if walking on the roof is necessary to minimize damage to cedar shakes.
Product Recommendation
Maxwell personally recommends Wet & Forget Moss Mold, Mildew, Algae Stain Remover. After application, wait for the lichen to die and wash off with rain. If needed, gentle scrubbing with a long-handled brush from a ladder can help, avoiding foot traffic on the roof.
