Proof & specs · Primary documents

Don't take our word for it. Read the documents.

Every claim on this site traces back to a warranty, a code evaluation, or an independent test report. All of them are hosted here, in full, unedited.

Product documents courtesy of Interlock Roofing; the EPA firm certificate is issued to Interlock Metal Roofing (New England) Inc. Product documents are published at interlockroofing.com and mirrored here for fast access.

Warranty

The Guardian Warranty — Guardian Lifetime Limited Material Warranty

Lifetime coverage for the original homeowner — never prorated, so it doesn't shrink as the roof ages. Transferable once: the next owner is covered to 50 years from substantial completion (transfer registered within 60 days; $300 fee). The Alunar® coating is warranted for 30 years. Warranted wind resistance of 120 mph (193 km/h) installed to manufacturer specification and hail coverage for stones up to 1.5 inches.

Lifetime coverage for the original owner
One-time transfer — 50 yrs for the buyer
120 mph warranted wind
1.5″ hail coverage

Read the full warranty (PDF)

US building code

ICC-ES Evaluation Report ESR-1790

The International Code Council Evaluation Service report covering Interlock aluminum roof panels and shingles for compliance with the International Building Code and International Residential Code — the document your building inspector actually checks. Reissued September 2025; current through September 2026. Panel weights run just 0.41–0.59 psf, a fraction of asphalt (~2.5 psf) or slate (~10 psf).

IBC & IRC compliance
Reissued Sept 2025
0.41–0.59 psf panel weight

Read ESR-1790 (PDF)

Impact / hail

UL 2218 Class 4 — Intertek listed

Class 4 is the highest impact-resistance rating there is: a 2-inch steel ball dropped from 20 feet, twice in the same spot, with no cracking of the panel. Interlock systems carry the rating under Intertek listing SPEC ID 33876 — the same rating many insurers reward with premium discounts.

Class 4 — highest rating
Intertek SPEC ID 33876
Ask your insurer about discounts

View the Intertek listing (PDF)

Canadian code

CCMC 10475-R — National Research Council of Canada

Interlock's Canadian Construction Materials Centre evaluation has been continuously active since October 24, 1983 — more than four decades of uninterrupted code listing in the harshest roofing climate in North America. Snow country is where this system was proven.

Active since 1983
40+ years continuously listed

Read CCMC 10475-R (PDF)

High-wind approval

Florida Product Approval FL7263-R7

Florida evaluates roofing products for wind performance under the Florida Building Code. Interlock systems hold approval FL7263-R7 (revision 7, August 2023), evaluated to the 8th Edition (2023) FBC by Robert Nieminen, P.E., with maximum design pressures from −30.0 to −187.5 psf depending on assembly — tested to UL 1897, UL 580 and TAS 125. The approval is non-HVHZ: it excludes Broward and Miami-Dade counties, and does not cover fire classification. It is evidence the interlocked, concealed-fastener design performs in wind zones far beyond anything a New England nor'easter delivers.

MDP to −187.5 psf
Rev. 7 · Aug 2023
Non-HVHZ

View FL7263-R7 (PDF)

Corrosion & finish

Alunar® coating — measured to ASTM methods

The finish is where a roof either lasts or doesn't. Alunar® is a PVDF fluorocarbon coating applied to a minimum 1.0 mil on the weather surface. It passed 1,000 hours of ASTM B117 salt-spray exposure at a rating of 7 or better and 2,000 hours of ASTM G155 accelerated weathering with no color change, flaking or cracking — the tests behind every claim we make about salt air and fading. The coating carries a 30-year warranty against chalking beyond a rating of 8 (ASTM D-4214) and fading beyond 5 Hunter ΔE (ASTM D-2244).

1,000-hr salt spray — ASTM B117
2,000-hr weathering — ASTM G155
30-yr coating warranty, measured thresholds

See the test results (PDF)

Lead-safe work practices

US EPA Lead-Safe Certified Firm — NAT-34864-4

Issued by the U.S. Environmental Protection Agency to Interlock Metal Roofing (New England) Inc. (formerly Interlock Industries, Inc.) on June 9, 2026, under Section 402 of the Toxic Substances Control Act and 40 CFR Part 745, for renovation, repair and painting work in pre-1978 homes and child-occupied facilities. Certified only for purposes of TSCA Section 402. Valid through June 23, 2031 in all EPA-administered states, tribes and territories — in New England, that means Connecticut, Maine and New Hampshire; Massachusetts, Rhode Island and Vermont run their own state programs.

Issued June 9, 2026
Expires June 23, 2031
CT · ME · NH (EPA-administered)

View the EPA certificate (PDF)What it means for your roof →

For architects, builders & inspectors

Full specification manuals

Complete architectural spec manuals for every Interlock profile — dimensions, fastening, flashing details, and installation standards.

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