The black streaks on Tampa tile are not dirt and not mold. They are a cyanobacterium colony, and how they get removed matters more than that they get removed, because the wrong method breaks tile and drives water under it.
Call (813) 742-0423Upfront pricing · No obligation · Local Hillsborough County technician
Six boxes, about thirty seconds. You pick when to be called back, and that is when the phone rings.
Or call (813) 742-0423The organism behind dark roof staining is Gloeocapsa magma, a cyanobacterium rather than an alga. It is airborne, it feeds on moisture and on calcium carbonate and limestone material in roofing products, and it gained notoriety across the Southeastern United States in the 1990s. As a colony matures it develops a dark, hard, ultraviolet-protective outer coating, and that coating is what you see. Gravity then pulls the colony downslope, which is why the staining reads as vertical smears rather than patches. Growth holds moisture against the surface it occupies, which is the mechanism behind the premature aging attributed to it. The rest of our tile services deal with water getting in; this page is about not creating that problem while cleaning.
A pressure washer solves the appearance and creates three new problems. First, tile is designed to be walked only in specific places, near the supported head lap and never mid-pan, and a person dragging a hose across an open field breaks pieces. Second, high pressure aimed uphill drives water under the head laps and directly onto the underlayment, which is the layer doing the actual waterproofing and the layer with the shortest remaining life. Third, on concrete tile it strips surface color and on older clay it works at the mortar in hip and ridge beds. The accepted approach for this organism is chemical rather than mechanical: sodium hypochlorite or copper sulfate solutions, applied at low pressure, with non-pressure application preferred specifically to avoid costly damage.
Two local factors set how fast staining returns. Shade is the first: a slope under live oak canopy stays damp between rains, and a damp surface with organic debris on it is a food source rather than a roof. Rain concentration is the second, since this city takes its water in intense summer downpours that wet the roof thoroughly and then leave it to bake. North-facing and shaded slopes stain first and worst. Moss, which is a plant rather than a bacterium, appears where debris has built enough depth to hold soil, typically in valleys, at ridge junctions and behind chimneys, and where moss is growing there is standing debris to clear regardless of appearance.
Anyone on a tile roof with a wand is standing on the most fragile roofing material in common use here. Older clay barrel tile is brittle enough that a cleaning visit routinely produces broken pieces, and on a profile that has been out of production for decades each break is a sourcing problem rather than a line item. That is worth knowing in both directions: insist that any cleaning scope state who replaces tile broken during the work, and take advantage of the access to have the ridge beds, valleys and penetrations looked at while someone is up there. A cleaning visit that produces a written note on trim mortar and valley debris is worth more than one that only produces a clean roof.
Roof condition is recorded by carriers, and staining and debris are visible in an inspection photograph. Citizens Property Insurance revised its roof rules to comply with Senate Bill 2-D, effective May 1, 2023 for new business and September 1, 2023 for renewals, and among those changes the condition rule referring to excessively patched areas was rewritten to remove its 25 percent reference. Citizens also states that it may conduct inspections at any time to verify that a roof continues to satisfy underwriting requirements. What follows from that is narrow and worth stating carefully: a documented, clean, debris-free roof photographs differently from a stained one, and no cleaning should ever be sold as producing a specific decision from a specific carrier.
Debris comes off first by hand, out of valleys, off ridge lines and out of gutters, because chemistry cannot reach a surface under a leaf mat. Solution is applied at low pressure and given dwell time rather than being scrubbed. Landscaping and gutters are protected and rinse water is managed. Foot traffic is planned along supported paths, and broken pieces are logged and replaced. Price follows roof area, pitch and height, how much debris has accumulated, how much shade the roof sits in, and whether tile replacement is expected. Ask whether the quote is for a chemical soft wash or for pressure, and decline pressure on tile. Two natural follow-ups: tile roof inspection, which uses the same access more productively, and roof ventilation, because a chronically damp attic and a chronically damp roof surface often share a cause.
Roof Cleaning, Moss and Algae in Tampa. Call (813) 742-0423 and a technician is dispatched with the parts on the truck. You get the price before the work starts.
Call (813) 742-0423Florida Building Code section 1203.2 requires 1 square foot of net free ventilating area per 150 square feet of attic, reducible to 1 per 300 where a Class I or II vapor retarder is used or where 40 to 50 percent of the area sits in the upper portion of the space at least 3 feet above the eave vents.
Why it matters: Poor ventilation keeps the roof deck hotter for longer, which shortens the life of the underlayment doing the waterproofing under tile.
Source: up.codes
The U.S. Army Corps of Engineers' Operation Blue Roof program, which installs fiber-reinforced sheeting on storm-damaged roofs at no cost, states that contractors cannot cover metal, clay or slate tile roofs, and that roofs with more than 50 percent structural damage to the framing do not qualify.
Why it matters: Tampa tile homeowners cannot treat the federal program as their post-storm fallback and have to plan their own emergency covering.
Source: usace.army.mil
Florida's code defines a secondary water barrier as underlayment protecting the sheathing if the covering blows off, and accepts either 4-inch self-adhering tape sealing all deck joints plus an approved underlayment, or a full-deck application; the Existing Building Code deems correctly installed clay and concrete tile systems to comply, and statute 553.844 bars limiting the requirement to one method.
Why it matters: It tells a tile owner the barrier is delivered through the underlayment specification, so the specification named on the scope of work is the barrier.
Sources: floridabuilding.org · up.codes · flsenate.gov
Upfront pricing · No obligation · Local Hillsborough County technician