How to Use This Roofing Resource

Attic Authority organizes roofing information across material types, installation methods, code frameworks, and geographic permitting contexts so that contractors, inspectors, and property owners can locate technically grounded reference content without sifting through marketing copy. This page explains how that content is structured, where its boundaries sit, what lookup methods yield the best results, and how factual accuracy is maintained. Understanding the organization logic reduces the time needed to move from a general question to a specific, verifiable answer.

How information is organized

Content on this site follows a layered classification model built around three primary axes: roofing system type, regulatory context, and project phase.

Roofing system types are divided into two top-level categories:

1. Low-slope systems (defined by NIST and most building codes as a pitch below 3:12) — including built-up roofing (BUR), modified bitumen, thermoplastic polyolefin (TPO), ethylene propylene diene monomer (EPDM), and spray polyurethane foam (SPF).
2. Steep-slope systems (pitch at or above 3:12) — including asphalt shingles, metal panels and shakes, clay and concrete tile, slate, and wood shakes.

This 3:12 threshold is not arbitrary. The International Residential Code (IRC), published by the International Code Council (ICC), uses this boundary to assign drainage requirements, fastener schedules, and underlayment specifications. Content pages are tagged to the appropriate slope category so comparisons between, for example, EPDM membrane installation and asphalt shingle installation remain grounded in the correct code context rather than blurred across incompatible system types.

Regulatory context layers sit beneath system-type classification. Federal agencies including the Occupational Safety and Health Administration (OSHA) and the Environmental Protection Agency (EPA) govern worker safety and material disposal. State and local jurisdictions adopt model codes — primarily the International Building Code (IBC) and IRC — with amendments that vary by state. The Roofing Directory Purpose and Scope page outlines how those jurisdictional layers interact within the directory structure.

Project phase classification sorts content into four stages: assessment and inspection, material selection, installation, and maintenance or repair. A reader researching flashing details for a valley intersection will find that content under installation, not under material selection, even if the article discusses metal alloy composition.

Limitations and scope

This resource covers roofing systems on residential and light commercial structures in the United States. It does not address heavy industrial facilities, underground waterproofing, or structures governed primarily by the ASCE 7 wind load standard without cross-reference to IBC or IRC frameworks.

Content scope excludes three categories by design:

1. Jurisdiction-specific permit schedules — Permit fee tables, inspection routing, and approval timelines differ at the county and municipal level across more than 3,000 jurisdictions. The Roofing Listings directory connects readers to licensed contractors who carry jurisdiction-specific permitting knowledge.
2. Product installation manuals — Manufacturer installation instructions for named products (e.g., GAF, Owens Corning, Firestone Building Products) supersede generic reference guidance. Links to manufacturer technical libraries are provided where relevant, but page content does not reproduce proprietary specifications.
3. Engineering calculations — Structural load analysis, rafter sizing, and deck deflection calculations require a licensed professional engineer. Reference content describes the regulatory triggers that require engineering review (for example, ICC Section 1604.3 governing deflection limits) without replicating the calculations themselves.

Safety framing appears throughout content sections involving fall hazards, electrical proximity, and chemical exposure. OSHA 29 CFR 1926 Subpart R governs steel erection and related fall protection requirements on roofing worksites; OSHA 29 CFR 1926.502 defines guardrail, safety net, and personal fall arrest system specifications. Content pages cite these standards by part number but do not constitute OSHA compliance documentation.

How to find specific topics

Three navigation paths serve different lookup needs:

1. By system type — Use the system-type taxonomy (low-slope vs. steep-slope, then material subcategory) when the material or assembly is already known. Example: locating TPO seam-welding tolerances starts at low-slope > thermoplastic > TPO > installation.
2. By code section — Use the regulatory index when a building department has flagged a specific code citation. Content pages are cross-referenced to IRC and IBC section numbers where the code language directly governs the described practice.
3. By project phase — Use the phase taxonomy when the material is undecided but the work stage is defined. A property owner determining whether an existing roof requires a permit before adding a second layer of shingles should navigate to assessment > permitting triggers, where IRC Section R908 re-roofing provisions are addressed.

The Roofing Topic Context page provides an orientation to how technical vocabulary is used consistently across articles, which is especially useful when code terms and trade terms differ (for instance, "roof covering" as defined in IBC Chapter 15 versus colloquial use of "roofing material").

For readers arriving without a specific system or code section in mind, keyword search against article titles returns results tagged to both system type and project phase simultaneously.

How content is verified

Every factual claim referencing a code section, material standard, or agency rule is traced to a named primary source before publication. Primary sources used throughout this resource include:

• ICC International Building Code and International Residential Code — accessed through the ICC Digital Codes library at codes.iccsafe.org
• OSHA 29 CFR 1926 — accessed through the Electronic Code of Federal Regulations at ecfr.gov
• ASTM International standards — including ASTM D3462 (asphalt shingles), ASTM D4637 (EPDM membranes), and ASTM E108 (fire classification), referenced by standard designation and edition year
• NRCA (National Roofing Contractors Association) technical guidelines — cited by publication title where used as secondary technical reference

Content is reviewed against the current adopted edition of each code; where states have adopted older editions (for example, states still operating under the 2018 IBC rather than the 2021 edition), version-specific differences are noted inline. Errors identified in published content can be submitted through the contact page with source documentation.

References

• International Code Council (ICC) — Publisher of the International Building Code (IBC) and International Residential Code (IRC), including slope thresholds, fastener schedules, and underlayment specifications referenced throughout this content.
• U.S. Occupational Safety and Health Administration (OSHA) — Roofing — Federal standards governing worker safety during roofing installation, repair, and inspection activities.
• U.S. Environmental Protection Agency (EPA) — Federal regulations on material disposal, including guidance relevant to roofing materials containing hazardous components.
• National Institute of Standards and Technology (NIST) — Federal agency providing technical definitions and measurement standards, including slope classification conventions used in building science.
• ASHRAE Standard 90.1 — Energy efficiency standard for buildings, relevant to roofing system insulation and thermal performance requirements adopted by many jurisdictions.
• International Residential Code (IRC) — ICC Digital Codes — Official online publication of the IRC, the primary model code governing steep- and low-slope roofing requirements for residential structures.
• National Roofing Contractors Association (NRCA) — Technical Resources — Industry technical guidelines and installation manuals widely referenced alongside model building codes for roofing system types including BUR, TPO, EPDM, and modified bitumen.