The Florida Building Code allows two pathways to compliance for tile roof attachment: prescriptive (following the published tables) or performance-based (demonstrating compliance via engineering analysis). The choice between them affects cost, complexity, and what is documented in your closeout package.
Prescriptive
The simpler pathway. The code's tables specify, for each wind zone and roof condition, the exact attachment method, fastener type, and pattern that must be used.
If your roof falls within the conditions the tables cover — typical residential geometry, wind speed in the published range, standard exposure category — the prescriptive method is straightforward and cost-effective.
Performance-Based
The more flexible pathway. A Florida-registered structural engineer performs a wind-load analysis for the specific roof and specifies an attachment method that meets or exceeds the calculated load.
The performance pathway is required when:
- The roof geometry is outside the prescriptive tables (compound hips, complex valleys, unusual pitches)
- The wind speed exceeds the table's coverage
- The exposure category requires more conservative attachment than the table provides
- The owner wants to optimize for the specific conditions (typically: reduce attachment cost where the tables are overly conservative)
What the 2026 code clarified
The 2026 update clarified the documentation required for performance-based attachment:
- Sealed engineering drawings showing the calculated loads and specified attachment
- Installation documentation matching the drawings (with photographs of attachment patterns)
- Final inspection sign-off referencing the sealed drawings
Previously this was looser; now it is explicit.
When performance-based saves money
Counter-intuitively, performance-based analysis can sometimes specify a less-aggressive attachment than the prescriptive table — saving labor and material on a large roof. This happens when the prescriptive table is conservative for the specific conditions and the engineering analysis can justify a more efficient attachment.
Typical case: a low-pitch, sheltered roof in a moderate wind zone. The prescriptive table assumes worst-case exposure; the engineering analysis can demonstrate that the actual exposure is less severe.
When performance-based costs money
The engineering analysis itself costs $1,500-$3,500 on a typical residential project. If the prescriptive method works for your roof, the engineering fee is a pure overhead.
For most standard residential projects in our service area, prescriptive is the right path. The engineering fee does not pay for itself.
What we recommend
For residential roofs with standard geometry, in defined wind zones, with conventional materials: prescriptive.
For estate work with complex geometry, unusual structural conditions, or where the owner wants to optimize the specification: performance-based.
For HVHZ work: always prescriptive unless the product's NOA explicitly references performance-based pathways. The HVHZ inspection process is calibrated to the prescriptive tables and is more streamlined when those tables are followed.
How to know which applies to your project
Ask the contractor. If the answer is "prescriptive," request the table reference (e.g., FBC Table 1507.3.7). If the answer is "performance-based," request the engineer's name, license number, and the date of the sealed drawing.
Both answers are valid. The wrong answer is a contractor who cannot tell you which path the project is following.
Filed under