CCMC 10475-R: Interlock's Canadian Code Compliance Explained
Quick answer
CCMC 10475-R is the Government of Canada evaluation confirming that Interlock Cedar and Interlock Slate aluminum roofing comply with the National Building Code of Canada 2015. Issued by the Canadian Construction Materials Centre, it is backed by wind-uplift, water-infiltration, salt-spray and impact testing, and Canadian building officials accept it as evidence for approval.
What is a CCMC evaluation?
In Canada, a homeowner or builder often needs to prove to the local building department that a product meets code, and the most widely recognized way to do that is a CCMC evaluation. The Canadian Construction Materials Centre is operated by the National Research Council of Canada and is the only construction code-compliance evaluation service run by the Government of Canada. A CCMC number represents an official opinion that a product complies with the National Building Code — and, in the Centre's own words, in most jurisdictions this document is sufficient evidence for approval by Canadian authorities. CCMC assessments are recognized by building-official associations in every province.
What does 10475-R cover?
CCMC 10475-R has been active since October 24, 1983 and was last updated May 28, 2025 — one of the longest continuously maintained roofing evaluations in Canada. Held by Interlock Roofing Ltd. of Delta, BC, it covers the Interlock Cedar and Interlock Slate profiles: 0.48 mm-plus PVDF-coated aluminum shingles, 265 mm by 460 mm, interlocking on all four sides. It confirms compliance with the National Building Code of Canada 2015, evaluated against the CCMC Technical Guide for Metal Roof Panels, recognizing the shingles as both an acceptable solution and an alternative solution under the Code.
What did the testing show?
A CCMC evaluation is only as strong as the evidence behind it, and 10475-R summarizes a thorough test program at CCMC-recognized laboratories. In dynamic water-infiltration testing the roof showed no leakage or damage at simulated wind speeds up to 154–170 km/h. Wind-uplift testing with two nails per shingle showed no permanent damage through the tested pressures, reaching an ultimate load of about 12.9 kPa (roughly 269 psf) before panels released. The coating passed salt-spray resistance at a rating of 7 or better after 1,000 hours, showed no colour change or cracking after 2,000 hours of accelerated weathering, and passed impact, adhesion, hardness and flexibility testing; the shingles also passed a traffic load of 900 N or more.
What the evaluation requires
Like any code evaluation, 10475-R comes with conditions your installer follows: the shingles install over solid sheathing on a minimum 1-in-4 roof slope, using aluminum nails, with proper underlayment, eave protection, and flashing per the NBC. Following those conditions is what keeps the compliance opinion — and your warranty — intact.
Frequently Asked Questions
What is CCMC 10475-R?
CCMC 10475-R is an evaluation from the Canadian Construction Materials Centre — part of the National Research Council of Canada — confirming that Interlock Cedar and Interlock Slate aluminum roofing comply with the National Building Code of Canada 2015. Canadian building officials accept it as evidence for approval.
Do Canadian building officials accept CCMC evaluations?
Yes. CCMC is the only construction code-compliance service operated by the Government of Canada, and its assessments are trusted by more than 6,000 regulators nationwide. In most jurisdictions a CCMC evaluation is sufficient evidence for approval by the authority having jurisdiction.
How much wind can an Interlock roof withstand under CCMC 10475-R?
Wind-uplift testing showed no permanent damage through the pressures tested, with an ultimate load reaching 12.9 kPa (about 269 psf) using two nails per shingle. In dynamic water-infiltration testing, the roof showed no leakage at simulated wind speeds up to 154–170 km/h.
How long has Interlock been CCMC evaluated?
CCMC 10475-R has been active since October 24, 1983, and was most recently updated on May 28, 2025 — a decades-long, continuously maintained evaluation that speaks to the product's long track record in the Canadian market.
Sources
- CCMC / National Research Council of Canada — Evaluation 10475-R — Interlock Cedar and Slate, NBC 2015
Explore Interlock Metal Roofing
Last reviewed 2026-07-11 · Reviewed by Scott Plumptree, Director of Marketing