Home / Requirements / 2021 IWUIC Class 1–2 Class A roof

2021 IWUIC Class 1 and 2 Class A roof-assembly path

The unamended 2021 IWUIC specifies a Class A tested roof assembly for Class 1 and Class 2 ignition-resistant construction.

A documented roof assembly can match the rating and test. The alternative approved noncombustible covering, deck, underlayment, profile-space, official class, project scope, and local amendments remain separate checks.

code · Jurisdictions adopting unamended 2021 IWUIC Chapter 5 · Last verified 2026-08-27 · JSON (CC BY 4.0)

Published requirement text

“a Class A rating when tested in accordance with ASTM E108 or UL 790”

2021 International Wildland-Urban Interface Code, Sections 504.2 and 505.2 — International Code Council

Where this instrument is documented

Instrument iwuic-2021.

Set a location to read how this instrument lands where you are.

Place	Force	Reach	Dated	Checks open	Source
Pennsylvania	active application documented	statewide	effective 2026-01-01	4	34 Pa. Code § 403.21 Uniform Construction Code

Each place page carries that place's boundary, project scope and open official checks in full; this page's JSON twin carries them per application.

Machine-readable constraints

Attribute	Operator	Value
assemblyRole	eq	roof-assembly
fireRating	eq	class-a
testStandard	in	astm-e108–ul-790

Products with documented matching attributes

Open the Build rules that quote this requirement

Product	Category	Status	Documented match evidence
Elastoflex SA P FR, Polyflex SA P FR, Elastobase V, Elastoflex SA V FR	roofing	Listed	3 cited fields Assembly role: roof assembly · Listing 8180-2305:0505, Design field Fire rating: class a · Listing 8180-2305:0505, Design field Test standard: ul 790 · Listing 8180-2305:0505, Approval field
Owens Corning Titanium FR 0.032-inch aluminum-panel roof assembly	roofing	Attribute match	3 cited fields Assembly role: roof assembly Fire rating: class a Test standard: astm e108
Owens Corning Titanium FR 26-gauge steel-panel roof assembly	roofing	Attribute match	3 cited fields Assembly role: roof assembly Fire rating: class a Test standard: astm e108
Owens Corning Titanium FR asphalt-shingle roof assembly	roofing	Attribute match	3 cited fields Assembly role: roof assembly Fire rating: class a Test standard: astm e108
Owens Corning Titanium FR concrete-or-clay-tile roof assembly	roofing	Attribute match	3 cited fields Assembly role: roof assembly Fire rating: class a Test standard: astm e108

Sources

2021 International Wildland-Urban Interface Code, Sections 504.2 and 505.2 — International Code Council (official). Accessed 2026-08-27.

2021 IWUIC Class 1 and 2 Class A roof-assembly path. FireApproved. https://fireapproved.com/requirements/iwuic-2021-class-1-2-class-a-roof-assembly/. Last verified 2026-08-27.