Roofing Warranties, Explained Honestly
What a lifetime warranty actually covers (and what it doesn't), how to verify who really stands behind your roof, how transfer at home sale works, and how metal and asphalt warranties differ — with the full governing warranty text and PDF on this page, so you can check every statement against the source.
TL;DR — The Guardian Interlock® warranty is a lifetime limited material warranty backed by the manufacturer, Interlock Roofing Ltd. — in effect for the life of the original purchaser while they own the home. It covers manufacturing defects that cause rusting, rotting, splitting, cracking (including hail perforation from stones 1.5" or less), curling, loss of impact resistance, or combustion; warrants wind resistance to 120 mph (193 km/h) when installed to manufacturer specification; and warrants the Alunar® coating for 30 years against chalking and fading measured to ASTM standards. It transfers one time to the next owner — 50 years of material coverage, $300 fee within 60 days of the sale. Your certified installation contractor provides a separate written workmanship warranty. The complete governing text is reproduced below.
Reviewed by Scott Plumptree, Director of Marketing · Last updated August 3, 2026 · Every statement on this page is drawn from the governing warranty text reproduced below.
What "Lifetime" Actually Covers — and What It Doesn't
"Lifetime" is the most used and least examined word in roofing. Here is precisely how it works on an Interlock roof, stated the same way the certificate states it — including the parts most roofing pages leave out.
| Covered by the Guardian Warranty | Not covered (know this before you buy any roof) |
|---|---|
| Manufacturing defects that result in rusting, rotting, splitting, cracking — including splitting, cracking, and perforation from hailstones 1.5" in diameter or less | Installation workmanship — covered instead by your installation contractor's separate written workmanship warranty |
| Defects causing curling, loss of impact resistance with age, or burning / supporting combustion | Severe-weather "Acts of God" (earthquake, fire, flood, lightning), hail larger than 1.5", and impact from foreign objects |
| Wind resistance to 120 mph (193 km/h) when installed to the manufacturer's recommended procedures | Problems that originate in the building, not the roof: settlement, inadequate ventilation, missing vapor barriers, condensation, and ice damming or snow-shedding damage |
| Alunar® coating: 30 years against chalking beyond an ASTM D4214 rating of 8 and fading beyond 5 Hunter ΔE units (ASTM D2244) | Normal wear: minor scratches and dents, dirt and mildew accumulation, and cosmetic effects that don't affect function, such as oil canning; copper's natural patina |
| Original purchaser: the manufacturer covers its material and labor costs to repair, refinish, or replace nonconforming product, at its discretion, for the purchaser's lifetime while they own the home | Second owner: coverage is materials only — labor costs are the second owner's responsibility (50-year term after transfer) |
That right-hand column is not fine print to hide — it is how roofing material warranties across the industry are structured, and knowing it is how you compare warranties honestly. The difference is in the left column: how much is covered, for whom, and for how long. The full exclusions text is below, verbatim.
Manufacturer-Backed vs. Installer-Backed: Who Really Stands Behind Your Roof?
This is the single most important question to ask about any roofing warranty — and the least asked. A warranty is a promise, and a promise is only as good as the party still standing behind it in year 25. Installing companies close, merge, and change names; a warranty issued only by the installer follows the fate of that business. A manufacturer-backed material warranty survives all of it, because the obligation belongs to the manufacturer of the product itself.
How to verify who backs a roofing warranty — any roofing warranty — in five checks:
- Read the warrantor's name in the certificate. Not the brochure — the certificate. The Guardian Warranty names the manufacturer, Interlock Roofing Ltd., as the warrantor.
- Look for a certificate number. A registered certificate number ties your specific roof to the manufacturer's records. Every Guardian Warranty is issued with one.
- Confirm a claims channel direct to the manufacturer. If every claim must route through the installing company, you don't have a manufacturer-backed warranty in practice. Guardian claims go straight to [email protected].
- Ask who certifies the installer. Interlock roofs are installed only by certified regional installation centers — never subcontracted — and the installer's separate workmanship warranty sits alongside the manufacturer's material warranty, not in place of it.
- Check that verbal promises appear in writing. The governing text controls. That is why the complete Guardian text is published on this page — compare anything you were told against it.
Transferability & Resale Value
A roof you never have to replace is worth the most on the day you sell — if the coverage transfers with the house. The Guardian Warranty is transferable one time, to the first subsequent registered owner of the home: within 60 days of the purchase, the new owner sends proof of purchase and the $300 transfer fee to Interlock Roofing Ltd. and receives a confirmation email as their proof of transfer. The second owner's material warranty then runs 50 years from substantial completion (coating 30 years), with labor costs the second owner's responsibility.
For sellers, that is a documented, manufacturer-backed answer to a buyer's biggest exterior question. For buyers, it means the roof — the most expensive component of the home's envelope — arrives with written coverage instead of a countdown to replacement. Step-by-step instructions, deadlines, and what the second owner receives: How to transfer a roofing warranty when you sell your home.
How Metal and Asphalt Warranties Differ
Comparing a metal roof to asphalt shingles on price alone misses where the two products differ most: the shape of the coverage over time. Typical asphalt shingle limited warranties concentrate their full coverage in an initial period, then step down over the remaining years on a prorated schedule — and commonly limit transferability to a short window early in the roof's life. The practical result is that an aging shingle roof carries little remaining coverage precisely when problems appear.
The Guardian material warranty is stated for the life of the original purchaser while they own the home, with the manufacturer covering material and labor costs for covered defects during that term, and defined 50-year material coverage for a second owner after transfer. When you compare certificates side by side — and you should, for any roof you consider — look at three lines: coverage in year 25, transfer terms, and who the warrantor is. The Guardian text for all three is on this page.
Finish Warranty vs. Substrate Warranty
Every metal roof actually carries two warranties, and they are not the same thing. The substrate warranty covers the panel material itself — for Interlock, the Guardian lifetime limited material coverage of the aluminum panel against defects causing rusting, rotting, splitting, cracking, or curling. The finish warranty covers the coating on that panel — the Alunar® 70% PVDF system, warranted for 30 years against chalking beyond an ASTM D4214 rating of 8 and color change beyond 5 Hunter ΔE units measured per ASTM D2244, under normal atmospheric conditions.
The distinction matters because marketing headlines usually quote whichever number is larger, and on many products the impressive figure is the paint warranty sitting on much weaker substrate terms. Aluminum changes that calculus at the substrate level: it contains no iron, so it cannot rust — which is why Interlock can warrant the panel for life. Full explainer: Substrate vs. finish warranties on a metal roof.
Roofing Warranty Questions, Answered
What does a lifetime roofing warranty actually cover?
Exactly what its governing text says — always read the document, not the headline. Interlock’s Guardian Warranty is a lifetime limited material warranty from the manufacturer: it covers manufacturing defects that result in rusting, rotting, splitting, cracking (including hail perforation from stones 1.5 inches or less), curling, loss of impact resistance, or burning, for the life of the original purchaser while they own the home. It also warrants wind resistance to 120 mph when installed to manufacturer specification and the Alunar® coating for 30 years. Installation workmanship is covered separately by your installation contractor’s own written warranty.
What warranty should a quality metal roof come with?
Four things: a manufacturer-backed material warranty with clearly stated lifetime coverage for the original owner; a measurable finish warranty for the coating (tied to ASTM standards, not adjectives); a stated wind-speed warranty; and a separate written workmanship warranty from the installer. The Guardian Warranty provides the first three — lifetime limited material coverage, a 30-year Alunar® coating warranty measured per ASTM D4214 and D2244, and a 120 mph wind warranty — and every certified Interlock installer provides the fourth.
What should homeowners look for in a roofing warranty?
Check who the warrantor is (the manufacturer, not just the installing company), what is covered and for whom (materials, labor, original owner vs. later owners), the exclusions list, the transfer terms (how many transfers, deadline, fee), how the finish warranty is measured, and how claims are filed. Then confirm every promise you were made verbally actually appears in the written certificate.
How do I verify that a roofing warranty is backed by the manufacturer and not just the installer?
Ask to see the warranty certificate before you sign, and check the warrantor named inside it. A manufacturer-backed warranty names the manufacturer (for Interlock roofs: Interlock Roofing Ltd.), carries a certificate number, and gives you a claims channel direct to the manufacturer — [email protected] — that works even if the installing company changes hands. An installer-only warranty is only as durable as the installing business itself. With Interlock, both layers exist: the manufacturer’s Guardian material warranty plus the certified installer’s workmanship warranty.
Can a roofing warranty transfer to a new homeowner when a house is sold?
Some can — check the certificate for the number of transfers allowed, the deadline, and the fee. The Guardian Warranty transfers one time, to the first subsequent registered owner: the new owner sends proof of purchase and the $300 transfer fee to Interlock Roofing Ltd. within 60 days of buying the home and receives a confirmation email as proof. The second owner’s material warranty then runs 50 years from substantial completion (coating 30 years), with labor costs the second owner’s responsibility.
What does a transferable roofing warranty mean and why does it matter for resale?
It means documented coverage passes with the house instead of dying at closing. For a buyer, an Interlock roof with a transferable Guardian Warranty removes the largest looming exterior expense — the roof — from their risk calculation, backed by the manufacturer in writing for 50 years. For a seller, that is a concrete, verifiable listing point most competing homes cannot match.
How do roofing warranties differ between metal and asphalt shingles?
Typical asphalt shingle limited warranties concentrate full coverage in an initial period, then step coverage down over time on a prorated schedule, and commonly restrict transfer to a short window early in the roof’s life. Premium metal material warranties are generally longer and flatter. The Guardian Warranty is stated for the life of the original purchaser while they own the home, with defined 50-year terms for a second owner after a one-time transfer — terms you can read in full at the bottom of this page and compare line by line against any shingle certificate.
What is the difference between a paint or finish warranty and a substrate warranty?
The substrate warranty covers the panel material itself — for Interlock, the Guardian Warranty’s lifetime limited material coverage against defects causing rusting, rotting, splitting, cracking, or curling. The finish warranty covers the coating on that panel: the Alunar® coating is warranted for 30 years against chalking beyond an ASTM D4214 rating of 8 and color change beyond 5 Hunter ΔE units (ASTM D2244). When comparing roofs, read both — a long finish warranty can sit on top of much weaker substrate terms.
What voids a metal roof warranty?
Under the Guardian Warranty: installation balances left unpaid more than 60 days, denying the manufacturer access to inspect or service the roof, product that has been removed and reinstalled or altered, the use of dissimilar metals or fasteners, repairs or alterations by trades unfamiliar with metal roofing, and damage that results from building-code violations. Standard exclusions also apply — severe weather “Acts of God,” hail over 1.5 inches, condensation from poor ventilation, ice damming, and normal cosmetic wear such as minor scratches or oil canning.
Do solar panel mounts void a roof warranty?
Not when installed properly. The Guardian Warranty excludes damage caused by the faulty installation or improper use of solar equipment — not solar itself. Coordinate the racking plan with your certified Interlock installer before panels go on, so mounting is compatible with the interlocking panel system and both warranties stay intact. See our solar hub for how a lifetime roof changes the solar math.
How do I make a warranty claim?
Email [email protected] (or write to Guardian Warranty Claims, Interlock Roofing Ltd., 9969 River Way, Delta, BC V4G 1M8) within 30 days of the issue becoming known. Include your name, address, contact number, warranty certificate number, a description of the issue, and photographs. The manufacturer inspects, and covered product is repaired, refinished, or replaced under the terms of the certificate.
The Guardian Warranty Document
The full governing warranty text is also reproduced below. If anything on this page and the governing text ever differ, the governing text prevails.
What does my roof warranty cover?
This is a material warranty for aluminum and copper roofing and cladding products manufactured by Interlock Roofing Ltd. (the “Manufacturer”). Interlock Roofing Ltd. warrants the Interlock® cedar shingle, tile, shake, slate, diamond and standing seam roofing panels, cladding and trims (“Product”) to be free from manufacturing defects that result in rusting, rotting, splitting, cracking (including splitting, cracking and perforation from hail stones measuring 1 1/2 inches in diameter or less) curling, losing impact resistance with age, burning and supporting combustion which manufacturing defect materially affects the Product's performance (“Nonconforming Product”), subject to the exclusions and limitations set forth in this certificate. Other products or materials used in the installation may have their own manufacturer's warranty. The installation contractor will provide you with a separate workmanship warranty.
The Manufacturer warrants that the Product will resist wind speeds of up to one hundred and twenty (120) mph (193kph) when installed in accordance with the manufacturer's recommended installation procedures or FL7263. If there is Nonconforming Product during the Purchaser's warranty term the Manufacturer will cover its material and labor costs to repair, refinish or replace same, at its sole discretion, subject to the exclusions, conditions and limitations set forth in this warranty. Repaired, refinished or replaced Product is warranted for the remainder of the Purchaser's original warranty term; however, in the event that 80% or more of the roofing system has been replaced under warranty, the warranty will duly expire after such replacement. The Manufacturer may at its sole discretion refund the Purchaser's original Product purchase price. Any other extraordinary costs and expenses beyond the Manufacturer's obligation set forth in this warranty shall be the Purchaser's responsibility.
The Purchaser agrees to: notify the Manufacturer immediately of any Nonconforming Product; provide the first opportunity to inspect the Product and provide all reasonable access to complete any service and cure any Nonconforming Product. This warranty will be issued to a maximum of 2 Purchasers only.
Who is the purchaser
The Purchaser is defined as the party whose name and signature appears on the purchase and sale contract and whose name is registered on title to the Property. The Purchaser's warranty remains in effect for the life of the Purchaser provided that he/she is the registered owner of the Property, subject to the exclusions and limitations set forth in this certificate.
Is the purchaser an organization?
If the Property is owned by an Organization (including but not limited to, a corporation, an unincorporated association, a condominium, a cooperative housing arrangement, a religious organization, a governmental or public entity or a trust) the Product is warranted for fifty (50) years from date of Substantial Completion, including the coating which is warranted for thirty (30) years from the date of Substantial Completion. A warranty extended to an Organization can not be transferred or assigned.
Coating Warranty for Aluminum
The Manufacturer further warrants that for a period of thirty (30) years from the Substantial Completion Date, the aluminum Product's Alunar® coating will not, under normal atmospheric conditions (this excludes corrosive, aggressive or industrial atmospheres such as those contaminated with acidic or chemical fumes) chalk in excess of a numerical rating of eight (8) when measured according to ASTM D-4214-07 (2015); fade or change color in excess of five (5) Hunter ΔE Units when measured according to ASTM D-2244-16. Color change shall be measured on an exposed painted surface that has been cleaned of surface soils and chalk, and the corresponding values measured on the original or unexposed painted surface. Fading or color changes may not be uniform if the surfaces are not equally exposed to the sun and elements.
When does the warranty take effect?
This warranty takes effect once the installation contract has been paid in full, without offset or withholding. This warranty will become null and void: if there are any outstanding amounts due, whether payable to the installation contractor or the manufacturer, that remain unpaid for more than 60 days after issue or where the installation or the manufacturer or their representatives and/or agents are denied access to the Property for inspections or service.
How do I transfer the warranty?
This warranty is transferable onetime only from the original Purchaser to the first subsequent registered owner of the Property (the “2nd Owner”). If the 2nd Owner is an Organization, the Organization must be the registered owner of the property. The warranty period for the 2nd Owner shall extend fifty (50) years from the Substantial Completion Date including the coating which is warranted for thirty (30) years from the date of Substantial Completion. This warranty can not otherwise be transferred or assigned. The 2nd Owner must send proof of the purchase of the Property to the Manufacturer within sixty (60) days of same with the $300.00 transfer fee (“Transfer Fee”). The Transfer Fee must be payable to Interlock Roofing Ltd. and mailed to the company at 9969 River Way, Delta, BC V4G 1M8. A confirmation email will be issued and is the 2nd Owner's proof of warranty transfer. If the warranty is not transferred, the Manufacturer will be relieved of all of its obligations to the 2nd owner.
2nd Owner's limited product warranty
Once transferred, the 2nd Owner's limited material warranty extends fifty (50) years from the Substantial Completion Date. If during the 2nd Owner's warranty term there is Nonconforming Product, the Manufacturer in its sole discretion, will cover its material costs to repair, refinish or replace the Nonconforming Product, subject to the exclusions, conditions and limitations set forth in this Warranty. Any and all labor costs associated with same will be the 2nd Owner's responsibility. Repaired, refinished or replaced Product is warranted for the remainder of the 2nd Owner's warranty term; however, in the event that 80% or more of the roofing system has been replaced under warranty, the warranty will duly expire after such replacement. The 2nd Owner must give the Manufacturer the first opportunity to inspect the Product and provide all reasonable access to complete service and cure any Nonconforming Product.
How do I register a claim?
A warranty claim must be submitted in writing by email to: [email protected]
or by regular mail to:
Attention: Guardian Warranty Claims
Interlock Roofing Ltd.
9969 River Way
Delta, BC V4G 1M8 Canada
The written statement should include your name, address, contact number, the warranty certificate # and a description of the issue. You will be required to submit, at your expense, photographs or other evidence of the claim. The warranty holder may be required to pay the costs of any color testing if the color loss proves to be within the measure units specified in this warranty. Written notice of a warranty claim must be provided to the Manufacturer within thirty (30) days of the issue becoming known to you. In the event it is not so notified, the Manufacturer will be relieved of its warranty obligations. The Manufacturer has sole discretion to determine whether the Product is considered Nonconforming. The Manufacturer must be given all reasonable opportunity and access to investigate a claim; travel charges may apply. Unnecessary inspections are costly and time consuming for both parties and the warranty holder will be responsible for a minimum $300.00 inspection charge for any inspection and/or service that is not a valid material warranty claim.
Safety First
Our prime concern is your safety. Every year there are thousands of emergency room visits due to falls from ladders and roofs. We recommend that you hire a skilled professional for work that requires access to or traversing your roof.
Metal roofing sheds rain, snow and ice. In northern climates, weather patterns may allow for large amounts of snow and ice to accumulate. Be aware that snow and ice can build-up and release unexpectedly and ensure that the release area is free from pedestrian traffic and other property during the winter months to avoid injury to people and damage to property.
Snow guards and snow-rails are designed to restrict the amount of snow and ice releasing but the use of these accessories may contribute to the build-up of snow and ice on your roof. If you would like additional snow guards installed on your roofing system or current snow guards removed or moved to another location, contact your installation contractor to arrange for this service. Snow guards and snow-rails are not a manufacturer's warranty issue and service charges will apply.
Care of your roof
To ensure your roofing system is looking and functioning its best we advise homeowners to have their gutters cleaned annually and have any branches or other debris on the roof removed promptly.
The slope of a roof, general weather conditions, surrounding tree and shade cover and wind and sun exposure are determining factors in the accumulation of dirt and mildew and vary significantly from home to home. Any residue on the roof may be cleaned from the ground by lightly hosing down the roof with a well-diluted nonabrasive liquid detergent and a long-poled soft bristle brush. Debris or other items on the roof may be removed from the ground by using a long rope or pole. We recommend that you hire a skilled professional for work that requires access to or traversing your roof.
Condensation is caused by high levels of humidity and a lack of ventilation. It is often mistaken for a leaking roof. Ensure that your attic and other roof cavities are well-ventilated and that your eaves are free from blockage. If you have condensation issues consult with a professional builder as this may be an indication of poor ventilation, inadequate insulation and/or the absence of a vapor barrier.
Warranty Exclusions
This warranty does not warrant against and does not cover damages of any kind when due to any of the following: severe weather events or other “Acts of God” (including but not limited to, earthquake, fire, flood and lightning); terrorism or other “Acts of War”; exposure to harmful chemicals, gases or toxins; impact of foreign objects; settlement or failure of any part of the building (including but not limited to the foundations, walls, chimneys, rafters, trusses or sheathing) and/or change in building use; inadequate or improper venting, insulation and/or vapor barriers; condensation; ice-damming; ice and snow shedding; hail damage (excluding splitting, cracking and perforation from hail stones 1.5 inches or less); pre-existing roof irregularities such as uneven roof lines, dips and/or sagging and pre-existing conditions including but not limited to mold.
This warranty also does not warrant against: the faulty installation or improper use of skylights, antennas, solar or hot water roofing system or high pressure washers; the use of accessories/products that do not properly receive, support or secure Interlock components; the use or installation of dissimilar metals including dissimilar metal fasteners. Roofing repairs, additions or alterations of any kind could affect your warranty so ensure your contractor or service provider is familiar with metal roofing and/or have them call us to get information about working with our product. Accidental or intentional damage and any damage which is a result of a violation or contravention of the building code will not be warranted in any way.
The warranty also does not warrant against: normal wear and tear, including minor scratches and dents; the accumulation of dirt and mildew and other organic material; normal weathering of the roofing surface including minor color differences and aesthetic issues that do not affect the function of the roof including but not limited to oil canning.
Product which has been removed and reinstalled and/or altered or changed in design or function is not warranted in any way.
Copper metal roofing naturally corrodes and tarnishes and therefore is not guaranteed against surface corrosion. While copper metal roofing develops into a patina, there is no guarantee that it will patina in a uniform manner or within a certain period of time as these factors are affected by environmental and atmospheric conditions.
Remedies and Limitations
The Manufacturer's liability and the Purchaser's exclusive remedy is limited to Product repair, replacement, refinishing or refund of the original Product Purchase price. The Manufacturer's liability and the 2nd Owner's exclusive remedy is limited to the Product repair, refinish or replacement and does not cover any labor costs whatsoever.
The Manufacturer's obligation under this warranty ends once the original Product Purchase price is refunded and/or where 80% of the roof has been replaced and its obligation under this warranty shall in no event exceed the original Product Purchase price.
Any controversy or claim arising out of or relating to this warranty or the breach thereof, shall be settled by binding arbitration in accordance with the rules and procedures of the American Arbitration Association or in Canada, the Canadian Arbitration Association.
The Manufacturer reserves the right to discontinue or make changes to its Products. In the event the Products covered by this warranty are not available, it shall have the right to substitute Product that, in its sole discretion, is of equal quality or price.
The Manufacturer shall not be liable for any incidental, special, or consequential damages of any kind, including any damage to the Property, its contents or any persons therein resulting from, but not limited to; ice, ice damming, snow or ice shedding. Some states/provinces/territories do not allow limitations on how long an implied warranty lasts or the exclusion or limitation of incidental or consequential damages so the above limitations may not apply to you.
This warranty shall not be modified or extended and no one is authorized to change this warranty in any way or grant any other warranty. This is the only written warranty provided by the Manufacturer. It reserves the right to cancel and/or modify this warranty without notice at any time; however, all fully paid warranties shall remain in force until their expiration.
This warranty gives you specific legal rights and you have other rights, which may vary from state/province/territory.
This warranty is expressly in lieu of any guarantee and/or warranties, oral or written, express or implied except as are set forth herein, including any implied warranty of merchantability or fitness for a particular purpose.
*Alunar, Interlock and Interlock Lifetime Roofing Systems are registered trademarks of I.E.L. Manufacturing Ltd. and used under license.
Certificate #:
Name(s):
Property Address:
Substantial Completion Date:
[If there is any conflict between the English and a translated version the English version will prevail.]
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