Does a tile roof need sealing after cleaning?

The first thing to settle is what the tile is made of, because the tile association's sentence about coating a roof covers one material only.

The Tile Roofing Industry Alliance writes: “Unlike most other roofs, a concrete tile roof can be recoated if desired.” Two words in it carry the answer to this page's question. Concrete limits the sentence to one material, and if desired makes the coat a choice. TRI goes on to recommend hiring a professional with experience in concrete tile for any work on such a roof.

The recoating sentence says nothing about clay. The TRI line that speaks to cleaning and resealing across both materials, “Periodic cleaning and resealing can rejuvenate and prolong the surface finish of either cement or clay tile,” is about keeping a finish looking renewed over time. It pairs resealing with cleaning without making the first a condition of the second, and it speaks of the finish rather than the roof.

Material and shape are separate questions. Eagle Roofing Products makes concrete tile as high barrel S-tile, which it calls semi-cylindrical, and as flat tile “completely lacking in any barrels or rolls”, so the profile on a roof does not by itself tell you whether TRI's concrete sentence applies to it.

Where TRI describes a clear coat on concrete tile, it describes a choice about appearance, with a verb that leaves it optional.

TRI says a clear coat of acrylic sealer “may be applied to renew the roof's original luster.” The verb is may and the purpose is luster. Neither turns the coat into the last step of a cleaning, and the sentence gives no protective purpose for the sealer at all.

The order TRI gives runs the other way. TRI puts a proper cleaning of the concrete tile roof by a professional ahead of the clear coat, and “Different preparation and coating methods may be used depending on the factory coloring process.” A cleaning comes before a coating when there is one; a coating is not what completes a cleaning. That sequence is taken up in whether a roof needs cleaning before it is coated or painted.

Whether a cleaning by itself brings back some of the color is a separate question, answered in whether roof cleaning brightens tile color.

A sealer can sound like a way to keep a clean roof clean. TRI's guide addresses that idea directly.

TRI writes: “While research continues, currently there is no known manufacturing procedure or coating applied on the job site that would have a long-term preventative effect on this condition.” The condition is mildew, algae and moss. The guide's next lines say the growth can be removed or treated, and “If the growth returns, treatment can be repeated as necessary.” Treatment, not a coating, is TRI's answer to returning growth, and the same line is quoted where this site sets out what a soft wash does not do for a roof.

Not every pale patch on concrete tile after a rain is something a coating would answer either. Eagle Roofing Products describes efflorescence as temporary light patterning on darker tiles, caused when alkaline deposits gravitate to a surface exposed to moisture, says every Eagle tile surface is treated to minimize it, and says that if it occurs “it will disappear completely after additional exposure to rain.” No sealer appears in that account.

Florida's contractor statute decides who may offer a coating with a protective promise attached.

Florida Statutes 489.105(3)(e) defines a roofing contractor's trade as covering all kinds of roofing, waterproofing and coating, “except when coating is not represented to protect, repair, waterproof, stop leaks, or extend the life of the roof.” Read the other way round, a coating represented to do any of those five things is roofing contractor work.

A companion section is narrower. Florida Statutes 489.117(4)(a)3 lets a local government that imposed the requirement before January 1, 2021 keep licensing rooftop painting, coating and cleaning above three stories, in the same sentence as veneer that includes gutters, siding, soffit and fascia. It is a local licensing carve-out, explained in why some rules mention roofs over three stories, not a rule about sealers.

None of this makes a clear coat forbidden or required. It means the words attached to a coating decide whether it falls in a roofing contractor's scope: a sealer offered for luster is described in TRI's terms, and one represented in any of the statute's five ways is roofing contractor work.

Put together, the sources leave sealing after cleaning as an owner's option on concrete tile, with the work and the wording each assigned.

• Material: TRI's recoating sentence covers concrete tile, and it is silent on recoating clay.
• Purpose: a clear acrylic coat renews luster in TRI's words, and TRI says no job-site coating has a long-term preventative effect on growth.
• Who does it: TRI recommends a professional with experience in concrete tile for any work on a concrete tile roof.
• What it may be called: a coating represented in any of the statute's five ways is roofing contractor work under 489.105(3)(e).

A cleaning, on this reading, is complete without a sealer. Whether a concrete tile roof then gets a clear coat is a separate decision for the owner and the professional who would apply it, and it is not part of the cleaning. How cleaning and the heavier work of recoating differ is compared in roof cleaning versus roof restoration.