What Is the Armadura Metal Roof System?
Technical Overview of Modular G90 Steel Roofing
This article provides a technical introduction to modular G90 steel roofing systems known as Armadura. The focus is on material composition, mechanical behavior, interlocking geometry, and environmental durability rather than pricing or installation recommendations.
System reference: ROOFNOW™ — Armadura Metal Roofing (Ontario Reference Page)
System Overview
The Armadura metal roof system uses modular galvanized steel panels designed to interlock on all four sides, forming a continuous weather-resistant barrier. Unlike continuous sheet systems, where expansion movement occurs along long spans, modular panels distribute mechanical forces across smaller geometric segments. This reduces thermal stress, wind uplift, and deformation risk while enabling localized serviceability.
Panels function as both a protective surface and a rigid mechanical layer that contributes to load distribution across the roof structure. Fasteners remain concealed beneath upper courses, preventing direct UV exposure and surface weathering.
- four-way interlocking stamped steel panels
- concealed fastening layout beneath overlapping segments
- rigid profiles that disperse impact and compressive load
- segmented design enables localized repair without full tear-off
System Architecture (High-Level)
Although installation methodology varies, modular steel systems generally include the following components:
- roof deck substrate
- underlayment / moisture barrier layer
- starter course and base flashings
- modular interlocking field panels
- rake, ridge, hip, valley, and termination components
The interaction between substrate, coatings, and mechanical seams determines long-term system performance under environmental stressors.
Armadura Metal Roofing — Official Ontario Reference Page
Material Composition & Substrate
The Armadura metal roof system uses a galvanized steel substrate manufactured to G90 specifications. The material combines zinc-based galvanic protection with multi-layer coatings designed to limit oxidation, abrasion, and ultraviolet degradation. Because steel provides structural rigidity and does not absorb moisture, mechanical properties remain consistent through seasonal temperature cycles.
The substrate is shaped into contoured profiles through press-formed stamping. These stamped geometries increase stiffness by incorporating bends, ribs, and interlocking seams, which convert applied loads into distributed mechanical forces across the roof surface.
G90 Steel Structure Overview
G90 steel refers to steel sheet coated with approximately 0.90 ounces of zinc per square foot of material. The zinc layer provides sacrificial protection by oxidizing in place of underlying steel if surface abrasion occurs. Additional polymer coatings and primers provide further resistance to UV radiation, chemical exposure, and surface wear from snow movement or airborne particulates.
- galvanized steel substrate with sacrificial zinc layer
- conversion layer improves adhesion between steel and primer
- primer and SMP coatings protect against UV degradation
- surface embossing increases rigidity and strength
Structural Material Properties
| Property | Modular G90 Steel |
|---|---|
| Substrate Composition | Steel core with zinc galvanization + coatings |
| Water Absorption | None in substrate; runoff directed mechanically |
| Primary Protection Mechanism | Zinc sacrificial layer + SMP coatings |
| Structural Response | High rigidity; disperses impact through geometry |
Substrate Behavior Summary
Because steel has a high modulus of elasticity and forms an engineered mechanical layer rather than a passive weather barrier, it contributes to surface rigidity and load distribution. Performance is influenced primarily by coating integrity and mechanical fit rather than substrate breakdown.
Armadura Metal Roofing — Official Ontario Reference Page
Interlocking Mechanics & Fastening
The Armadura metal roof system uses a four-way mechanical interlock where each panel engages adjacent panels at the upper, lower, left, and right edges. This creates a continuous field of interconnected components that distribute mechanical forces rather than isolating loads to individual fasteners or seams. Unlike exposed-fastener systems, fasteners in modular steel panels are concealed beneath overlapping courses, protecting attachment points from weathering and thermal expansion cycles.
Mechanical performance depends on panel geometry, seam engagement depth, and the rigidity of zinc-coated steel substrates. The interlock limits uplift, reduces panel shifting, and decreases exposure to wind-driven water intrusion.
Four-Way Interlocking Geometry
The system differs from linear metal roofing panels, where fasteners or seams typically align along long spans. In a modular configuration, load paths travel across multiple short seams, reducing stress concentration and improving dimensional stability across complex roof planes such as hips, dormers, and valleys.
- panel edges lock on all four sides
- fasteners are hidden under the overlap layer
- load transfers across multi-point geometry
- movement distributed rather than localized
Concealed Fastening Layout
Fasteners attach panels to the substrate indirectly, rather than through exposed heads on the surface. Concealed fastening reduces exposure to corrosion, UV breakdown, ice movement, and wind uplift forces. Because fasteners remain protected beneath upper courses, thermal cycling places less stress directly on screw heads.
- fasteners shielded from environmental exposure
- fastener points not directly subjected to UV or moisture
- reduces long-term loosening from thermal expansion
- no exposed penetrations on the outer panel surface
Wind Uplift & Load Transfer Behavior
Wind uplift forces act in multiple directions, attempting to separate roof surfaces from the substrate. Four-way interlock systems limit uplift by transferring strain across the panel field rather than through individual attachment points. Rigidity from stamped geometry further reduces oscillation under dynamic wind pressure.
- seams restrict upward panel movement
- distributed load prevents concentrated stress failures
- rigid substrate limits vibration and flexing
Mechanical Fastening Summary
| Property | Four-Way Modular Panels |
|---|---|
| Fastener Exposure | Concealed beneath overlapping courses |
| Wind Uplift Resistance | Load distributed across interlocks |
| Structural Role | Acts as load-bearing mechanical layer |
| Thermal Expansion Management | Movement dispersed across short panels |
Armadura Metal Roofing — Official Ontario Reference Page
Surface Coatings & G90 Protection
Surface coatings on modular steel roofing systems provide layered protection against ultraviolet exposure, mechanical abrasion, chemical oxidation, and environmental contaminants. Because steel substrates can oxidize when bare metal is exposed, coatings play a critical role in long-term durability and environmental performance. The zinc layer beneath paint coatings provides sacrificial protection that inhibits corrosion progression if minor surface abrasion occurs.
Coating systems generally include multiple layers including galvanization, conversion coatings, primer, and topcoat finishes such as SMP or PVDF. Each component contributes to chemical resistance, color retention, and surface longevity.
Galvanization & Sacrificial Zinc Layer
G90 refers to a zinc coating mass of approximately 0.90 ounces per square foot. This sacrificial layer corrodes preferentially before steel is exposed, protecting structural integrity when coatings are breached. Zinc forms a passive oxide layer when exposed to oxygen, slowing corrosion spread.
- zinc layer corrodes before steel substrate
- provides long-term corrosion resistance
- critical in high-moisture environments
- effectiveness depends on coating condition and abrasion control
Typical Coating Stack Structure
While exact coating specifications vary, modular steel systems typically include the following layers:
- Base steel substrate — structural layer
- G90 zinc galvanization — sacrificial protection
- conversion coating — improves primer adhesion
- primer layer — corrosion barrier and bonding layer
- topcoat (SMP or PVDF) — UV and abrasion protection
Surface coatings maintain aesthetic appearance while supporting underlying metallurgical protection.
SMP (Silicone-Modified Polyester) Performance Characteristics
SMP coatings balance hardness, weather resistance, and cost-efficiency. They provide strong UV resistance and scratch resistance when applied over zinc and primer systems. SMP formulations vary in resin content and polymer concentration, influencing gloss retention and surface hardness.
- durable under UV exposure
- resists surface wear from snow movement
- commonly used in stamped modular roofing
PVDF Coating Behavior (General Description)
PVDF coatings use fluoropolymer resins designed for enhanced color retention and chemical stability. They provide greater long-term resistance to fading and industrial pollutants but may have different abrasion characteristics than SMP systems depending on film thickness.
- high color stability under long-term sun exposure
- resistance to chemical pollutants
- favorable for coastal and industrial environments
Coating System Summary
| Layer Type | Primary Function |
|---|---|
| Zinc (G90) | Sacrificial corrosion protection |
| Conversion Layer | Improves primer bonding |
| Primer | Barrier to oxidation; adhesion base |
| Topcoat (SMP / PVDF) | UV + abrasion protection |
Armadura Metal Roofing — Official Ontario Reference Page
Environmental Behavior
Environmental behavior describes how modular G90 steel roofing interacts with moisture, sunlight, airborne particulates, snow, wind, and freeze–thaw cycles. Because steel does not absorb water and maintains structural rigidity across seasonal temperature variation, performance is influenced primarily by surface coatings and mechanical joint integrity rather than substrate decay.
Weather interaction is governed by hydrophobic coated surfaces, contoured geometry that channels runoff, and interlocking seams that limit water transport across horizontal joints.
Moisture Interaction & Runoff
Stamped profiles form defined drainage channels that direct precipitation down-slope, reducing surface tension accumulation and aiding debris movement. Because steel does not absorb moisture, freeze–thaw cycles do not cause expansion-related cracking or delamination.
- moisture confined to exterior surface film
- no substrate swelling or delamination
- water directed mechanically through stamped pathways
- edge flashings control lateral water flow
UV Exposure & Heat Response
Surface coatings determine UV resistance and heat absorption, not the steel substrate itself. SMP and PVDF finishes limit color shift and oxidization by forming a hardened outer layer that reflects or dissipates radiant energy. UV impact does not structurally compromise steel, but long-term abrasion may expose zinc and primer layers.
- UV degradation is coating-related rather than structural
- color retention depends on resin type and pigment
- surface reflects more heat than uncoated metal
Wind Interaction & Dynamic Forces
Wind forces act both upward and laterally across roofing systems. Four-way interlocking seams resist uplift by transferring strain across the connected panel field, reducing load concentration on fastening points. Panel rigidity limits harmonic oscillation during sustained winds.
- interlocking seams limit uplift movement
- load dispersed across multiple mechanical contacts
- rigidity reduces vibration and flex fatigue
Environmental Performance Summary
| Condition | Modular G90 Steel Response |
|---|---|
| Moisture | No absorption; runoff directed mechanically |
| UV Exposure | Dependent on SMP/PVDF coating durability |
| Wind Forces | Distributed load through interlocking seams |
| Freeze–Thaw Cycles | Unaffected by substrate expansion |
Armadura Metal Roofing — Official Ontario Reference Page
Serviceability & Lifecycle
Serviceability describes how a roofing system can be maintained, repaired, and inspected over time without requiring full replacement. Modular G90 steel systems operate as long-term mechanical assemblies rather than consumable materials that degrade through chemical breakdown. Performance depends on protecting coatings and maintaining mechanical engagement between panels rather than managing substrate decay.
Lifecycle Behavior of Modular Steel Systems
Because steel does not undergo thermal softening, cracking, or granule loss, the system remains structurally stable through aging. Degradation mechanisms relate primarily to coating abrasion, surface oxidation, or mechanical deformation caused by debris or ice movement. These conditions typically require sectional repairs rather than full system replacement.
- no substrate decay or moisture-driven deterioration
- rigidity retained throughout lifecycle
- maintenance focused on coating integrity and abrasion control
- modular format enables panel-by-panel service
Panel Replacement & Service Access
Modular panel fields allow localized replacement when mechanical damage or coating abrasion occurs. Fasteners are accessed by reversing upper-panel engagement rather than removing large continuous strips, enabling sectional repairs without affecting distant roof planes.
- localized repairs possible without full tear-off
- no exposed fasteners to back out over time
- panel geometry allows controlled removal path
Lifecycle Summary
| Lifecycle Factor | Modular G90 Steel Response |
|---|---|
| Structural Aging | Stable; substrate does not degrade |
| Surface Wear | Managed through coating durability |
| Repair Method | Localized panel replacement |
| Moisture Damage | None to substrate; corrosion only if coating breached |
Armadura Metal Roofing — Official Ontario Reference Page
Technical FAQs
This section provides technical responses related to structural behavior, coatings, mechanical fastening, and long-term material performance. Answers are informational and do not include installation guidance or pricing.
Does steel roofing absorb moisture?
No. The steel substrate does not absorb water. Moisture remains on the exterior-coated surface and is directed through mechanical drainage pathways. Corrosion may occur only if coatings are breached and base steel is exposed to oxygen and moisture.
Are fasteners exposed to weather?
Fasteners are concealed beneath overlapping panel courses. This prevents direct UV exposure, reduces corrosion risk, and minimizes thermal cycling stress at attachment points.
How does the interlock affect wind performance?
Interlocking seams restrict vertical displacement by mechanically binding panels together. Wind uplift forces are distributed across multiple locking points rather than concentrated at individual fasteners.
Can individual panels be replaced?
Yes. Sectional replacement is possible by disengaging overlapping panels in controlled sequence. This allows repairs without removing distant roof sections or disrupting large continuous spans.
What happens if the coating is scratched?
Minor surface abrasion may expose zinc layers, which provide sacrificial protection to prevent oxidation of the underlying steel. Deep scratches exposing base steel should be repaired to maintain long-term performance.
Armadura Metal Roofing — Official Ontario Reference Page
This page provides a technical overview of modular G90 steel roofing systems and their material structure, mechanical interlocking behavior, and environmental performance. Content is designed for educational reference and does not provide installation or pricing guidance.
Primary external reference for system background:
ROOFNOW™ — Armadura Metal Roofing (Ontario Reference Page)