Can roof cleaning help sell a house?

Three measures follow a roof through a Florida sale, and each one belongs to someone other than the seller or a cleaner: the buyer's insurer, an inspector that insurer approves, and a real estate licensee.

• Its age, by date. Florida Statutes 627.7011(5)(d) says “a roof's age shall be calculated using the last date on which 100 percent of the roof's surface area was built or replaced in accordance with the building code in effect at that time.” For a roof less than 15 years old, 627.7011(5)(b) bars an insurer from refusing to issue or renew a homeowner's policy “solely because of the age of the roof.” Under (5)(e), the subsection applies to policies issued or renewed on or after July 1, 2022.
• Its useful life, in an approved inspector's finding. For a roof at least 15 years old, the subsection turns on an inspection by an authorized inspector, which 627.7011(5)(a) defines as an inspector “who is approved by the insurer” and who is one of six listed kinds. The list runs from home inspectors and building code inspectors through contractors, engineers and architects, and the sixth kind is whoever the insurer itself recognizes as qualified. No listed kind names a cleaning company, and in every case the insurer's approval is what makes an inspector authorized.
• What a licensee must disclose. Under Florida Statutes 475.278, real estate licensees are presumed to be transaction brokers unless another relationship is set in writing, and a transaction broker's duties include “disclosing all known facts that materially affect the value of residential real property and are not readily observable to the buyer.” A single agent's duties under 475.278(3)(a) carry the same words.

A cleaning takes nothing off the first measure, supplies nothing to the second and settles nothing about the third. What the inspection right means for a homeowner facing a replacement demand is set out in the right to an inspection before an insurer requires a new roof, and the 15-year rule is quoted in full under the Florida rules that touch a roof cleaning.

What a cleaning reaches is appearance. The Asphalt Roofing Manufacturers Association describes algae discoloration as having “a brown to black appearance” that “may be mistaken for fungus growth, soot, dirt, moss, or tree droppings.”

ARMA also says the stain is most readily visible on light-colored roofs, so the roof's own color decides much of how far a cleaning changes the view from the street.

On asphalt shingles, ARMA separates looks from function in a single sentence: “There is no scientific evidence that algae is damaging to asphalt shingles, although it certainly affects the aesthetics of a roof.” GAF says the dark stains are often caused by Gloeocapsa magma, and ARMA's bulletin names it with a hedge, as “probably the most prevalent of several algae species that contribute to discoloration.” Why that stain reads so strongly in a listing image is its own question, answered in why a clean roof photographs differently.

A seller timing a cleaning against a listing date is working with a result the trade itself describes as temporary. ARMA's technical bulletin, revised June 2024, opens that part plainly, “Algae discoloration can be difficult to remove from roofing surfaces,” and closes it with the ceiling: “The effectiveness of such cleaning is only temporary, and the discoloration may recur.”

For tile, the Tile Roofing Industry Alliance places the growth first: “Mildew, algae and moss do not grow directly on tile but on the accumulation of dust and other organic materials that settle on tile.” It “can be treated to restore the original look,” and “If the growth returns, treatment can be repeated as necessary.” That last phrase is a condition, not a schedule.

How long a Naples roof keeps its color after a soft washing is taken up in how long a roof stays clean. The fair summary here is that no bulletin read for this page says the color will hold through a listing period of any length.

If a cleaning happens before a listing, the method is the part a seller can check. ARMA's bulletin says “DO NOT use a power washer or any type of brush or broom to clean algae from the roof surface,” and GAF's bulletin gives the shingle reason: power washing “may dislodge granules, which can lead to premature shingle failure.” That is why the trade's answer is soft washing, low pressure with a cleaning solution doing the work, rather than pressure washing.

A cleaning is also not a report on the roof. A cracked tile or a leak is a question for a roofing contractor, which is where TRI Alliance sends broken tile and where the line is drawn under where a cleaning stops and a roofing contractor starts. A stain coming off tells a seller nothing about what is under it, in either direction.

Whether the whole exterior is worth cleaning before a sale is weighed in whether exterior cleaning is worth it before selling. On the roof alone the fair reading is narrow. Whether a roof cleaning can help sell a house is not something the roofing bulletins or the statutes measure; what they describe is a change in how the roof looks. 239 Exteriors' own roof line stays inside that: roof cleaning removes organic buildup while “helping protect the look of your home.”