TSP

GAF's Technical Advisory Bulletin TAB-R-102, dated September 19, 2024, publishes a cleaning mixture in plain measurements: 4 gallons of water, 1 gallon of bleach and 1 cup of TSP. GAF expands the abbreviation itself, in parentheses, as "Tri-Sodium Phosphate-or acceptable phosphate-free substitute."

That parenthetical does two jobs. It names the chemical, and it tells the reader TSP is not the only ingredient GAF accepts in that line of the recipe: a substitute without phosphate is allowed, though GAF names no substitute product and does not say what makes one acceptable. The label word has its own entry, phosphate-free. GAF's instruction then continues: apply the mixture with a garden sprayer, let it sit on the roof surface for up to 20 minutes, rinse with low-pressure water, and protect any shrubs below.

That is GAF's printed bulletin for GAF shingles, read the way GAF wrote it, not a description of how any other roof gets cleaned.

The word phosphate turns up again in a document that has nothing to do with shingles. Florida's Department of Environmental Protection, in its recommended best management practices for mobile vehicle and equipment washing, tells a washer to "Use products that are labeled 'phosphate free'" and says detergents and soaps used in washing should be approximately pH neutral.

FDEP's document is written for washing vehicles and equipment, not roofs, and it never names TSP. The two documents meet only at the word phosphate: GAF allows a substitute without it in a mixture for its own shingles, and FDEP asks a mobile washer for products labeled without it. Neither turns the other into a rule for a roof.

GAF's mixture, TSP and all, is GAF's own instruction for GAF shingles. Neither TSP nor a phosphate-free requirement appears in the other roofing maker and association documents read for this entry, so the word belongs to GAF's recipe, not to a rule that reaches tile or metal.

Whether a mixture written for one maker's shingles carries over to a tile roof is its own question, answered at whether tile and shingle share a solution. The other published roof ingredients, bleach and water on shingle and a mild detergent on metal among them, are set side by side at what is in a soft wash solution.