In Vancouver, you can install a metal roof over existing shingles when the deck is sound, the new metal system fastens to the structure (not the shingles), underlayment and ventilation are upgraded, and local bylaws and manufacturer instructions are followed—done right, it’s durable and compliant. metal roof over shingles Vancouver

• Verify deck health and number of layers (≤1).
• Choose direct-to-deck metal or a ventilated batten system.
• Use high-temp, self-adhered underlayment over shingles.
• Fasten into framing; extend fastener length appropriately.
• Balance intake/exhaust ventilation; seal edges with closures.

Why this question matters in Vancouver

I install metal across Metro Vancouver’s wet microclimates: long damp seasons, wind-driven rain, and occasional salt influence near bays and inlets. Tear-offs are messy and expensive. A compliant metal-over-shingle recover can save disposal costs and time—if we satisfy code intent, manufacturer instructions, and building science.

What “metal over shingles” actually means

A true recover doesn’t lean on the old shingles for strength. The new metal assembly is complete and separate, transferring loads to the deck or framing through clips or screws. That’s a central principle in model codes and industry guidance on “roof recover vs. replacement.” In short: independent structure, sound substrate, limited existing layers. ( ibhs.org [1])

Vancouver’s rules of the road (what the by-law cares about)

The Vancouver Building By-law (VBBL) points you to Section 9.26 for roofing fundamentals: materials must meet listed standards and be installed per the manufacturer’s written instructions. That’s the backbone of compliance for a metal recover—if the panel system and details are approved for recover over shingles, and the deck is fit, the code pathway exists. ( BC Publications [2])

Industry standards you’ll see on my specs

For architectural sheet metal, I align details with the RCABC Architectural Sheet Metal (ASM) Standard—flashings, underlayment, panel practices, penetrations. It doesn’t promote “shortcut” overlays; it enforces good assemblies: membrane coverage, hems, closures, and compatible metals. These details matter even more on recovers because you’re isolating new metal from an older substrate. ( rpm.rcabc.org [3])

Two ways to build it right

There are two canonical methods for metal over existing roofing:

1. Direct-to-deck: We install a high-temperature, self-adhered underlayment over the shingles, then fasten panels/clips through into the deck or framing. This relies on flatness; any shingle ridges are ironed down by membrane and panel geometry.
2. Over-battens (ventilated): We add a batten/counter-batten grid, creating a drainage/vent space under the panels. It decouples the metal from any minor unevenness and encourages drying. It also adds thickness and needs carefully detailed perimeters and penetrations.

Both approaches are well-documented in metal-retrofit literature and are widely used when conditions are right. ( metalconstruction.org [4])

When I recommend a recover—and when I won’t

I will consider metal-over-shingle when:

• There’s one layer of shingles in decent shape (no active leaks, no saturated felt).
• The deck is solid(fastener pull tests pass; no spongy sheathing).
• The roof shape is cooperative (no low-slope dead zones without redesign).
• The manufacturer explicitly allows recover for the selected profile, with the specified underlayment.

I won’t recommend recover when:

• There are two or more layers of existing roofing.
• The assembly is water-soaked or deck damage is evident.
• Slope is below the panel profile minimum (e.g., standing seam at 2:12 without mechanical locks).
• We can’t deliver balanced ventilation and proper edge/valley detailing with the overlay.

Model-code and insurer guidance is blunt on the “two-layers” issue and substrate condition. Recover is a privilege, not a default. ( nrcawebstorage.blob.core.windows.net [5])

Permit and paperwork sanity

Does Vancouver require a building permit for every re-roof? It depends on scope and whether you’re altering structure or the building envelope beyond a straight replacement. The city’s guidance makes clear that permits are required for defined construction activities; for re-roofs, we confirm project-specific needs with the Authority Having Jurisdiction before work starts. No surprises, no stop-work. ( City of Vancouver [6])

Underlayment and fire/heat behavior

Over a shingle field, I specify a high-temperature, self-adhered membrane full-coverage. It seals nails, tames frictional movement, improves fire performance, and adds a continuous air/water barrier under the panels. This isn’t the place for low-temp felts; we’re under a dark metal skin that gets hot in summer. Industry guidance on reroofing emphasizes correct underlayment as part of the recover package. ( nrcawebstorage.blob.core.windows.net [5])

Ventilation: quiet, dry, durable

Recovers only succeed long-term when the attic or panel cavity breathes. I design continuous soffit intake and a ridge exhaust, with baffles to keep air paths open above insulation. That’s how we control dew points, protect sheathing, and keep roofs quiet in storm cycles. The decades-old “1/150” free-vent area rule of thumb remains a useful baseline for ventilated attics. ( nrca.net [7])

Fasteners, clips, and length math

With an overlay, fastener length increases —we’re penetrating membrane, shingle thickness, and into deck. For standing seam, concealed clips carry panel movement; at perimeters and corners we tighten spacing per the profile’s engineering tables. This is not guesswork. We document edge/corner schedules so uplift zones are handled like they should be.

Edges, valleys, penetrations: the leak calculus

Wind-driven rain finds edges and interruptions first. Recovers add complexity at perimeters because the finished thickness increases. I hem eaves, install foam closures, and use back-pans and diverters at chimneys, skylights, and wall upstands. Valleys get membrane plus metal liners, fully tabbed and hemmed. These aren’t “extras.” They’re the difference between a durable recover and a callback after the first atmospheric river.

Direct-to-deck vs. over-battens: which is better here?

If your roof planes are flat, direct-to-deck is simpler, lower-profile, and cost-efficient. If the surface is wavy or you want an air channel beneath panels for enhanced dry-out or energy reasons, battens make sense. Battens demand exact eave/rake detailing to close off wildlife and wind paths; done right, they’re whisper-quiet and robust. The metal industry’s retrofit papers outline both approaches; I use them as checklists, not sales brochures. ( metalconstruction.org [4])

Weight and structure

Metal is light. Even over shingles, a standing seam or stamped metal shingle system typically reduces dead load compared with tile or multiple asphalt layers. That said, we still evaluate framing at over-spanned rafters, heavily notched tails, or spot-repaired areas. A recover isn’t a workaround for structural neglect; it’s a finish system change with the same engineering accountability as a tear-off.

Noise and comfort

You’ve heard the myth: “Metal over shingles will be loud.” In reality, the membrane + shingle layer + deck stack increases mass and damping; the result is quiet—often quieter than direct-to-deck over bare sheathing. If you still want silence turned up, the ventilated batten approach adds an acoustic break that tames impact sound even further. standing seam vs shingles Vancouver

Moisture risk and why we sometimes insist on tear-off

If the existing assembly is wet, recover locks in moisture. That’s a no. If we see chronic condensation from bath fans dumping into the attic, or deck staining around a dead-valley, or fungal odor at the eaves, we tear off, fix the cause, then re-roof. Shortcuts rot wood. A durable recover starts with a dry, ventilated base.

Cost and schedule realities (and disposal wins)

Recovers usually save time and dump fees, especially where access is tight. We still budget for plywood spot repairs and detailed flashings; we just avoid days of tear-off, weather exposure, and hauling. On a typical 2,000–2,500 ft² roof, that can be thousands saved—and a shorter, cleaner site window. metal roof cost Vancouver

Warranty hygiene

Manufacturer weathertight warranties (where offered) and finish warranties hinge on following the book: underlayment type, fastener patterns, minimum slopes, and compatible metals. The RCABC standards add local discipline to flashing and edge details—useful for long-term serviceability and credible guarantees. Keep all product labels and lot numbers; they matter if you ever need coverage. ( rpm.rcabc.org [3])

Environmental upside

Leaving one clean layer of shingles beneath your new metal roof reduces landfill volume and transport emissions. Pair that with a PVDF-finished, cool-colour panel and proper ventilation and you’ve got a roof that’s durable, low-maintenance, and energy-aware. Small choices; big arc.

Your yes/no checklist for metal over shingles in Metro Vancouver

• One existing shingle layer only; deck is dry and solid.
• Panel profile minimum slope satisfied (2:12 mechanical-lock standing seam is common; confirm profile).
• Manufacturer documentation explicitly allows recover.
• Full-coverage high-temp membrane over shingles.
• Balanced ventilation plan and baffles.
• Edge/corner fastening schedule documented.
• Penetrations curbed and back-panned; eaves hemmed; closures everywhere they belong.
• Permit/inspection confirmed with the City (if required by scope). ( BC Publications [2], City of Vancouver [6])

People Also Ask — straight answers that earn the snippet

Can you install a metal roof over shingles in Vancouver?

Yes—when the deck is sound, there’s only one shingle layer, the panel system is rated for recover, and we upgrade underlayment and ventilation. We fasten into deck or framing, not shingles. We also confirm city requirements and the manufacturer’s instructions before work starts. ( BC Publications [2], ibhs.org [1])

Do I need a permit to put metal over shingles?

Permit needs depend on scope. Straight re-roofing without structural changes may proceed under standard guidelines; broader envelope or structural work can trigger permits. We check with the Authority Having Jurisdiction (City of Vancouver) at the proposal stage to avoid surprises. ( City of Vancouver [6])

Is metal over shingles quieter or louder?

Quieter in most homes. The old shingles and the self-adhered membrane add mass and damping under the metal, reducing impact sound. A ventilated batten build is even calmer because the air gap breaks resonance paths. Good edge detailing prevents whistles.

What if my roof already has two layers of shingles?

Then we tear off. Model-code and insurer guidance call for replacement—not recover—when two or more layers exist or the substrate is wet or deteriorated. Recover is only permitted over a single, serviceable layer with a sound deck. ( nrcawebstorage.blob.core.windows.net [5])

What underlayment do you use over shingles?

A high-temperature, self-adhered membrane, full-coverage. It seals around fasteners, damps panel movement, and tolerates the heat a dark metal skin can generate. It’s the right choice under metal in our climate and aligns with reroofing best-practice guidance. ( nrcawebstorage.blob.core.windows.net [5])

Will ventilation still work after a recover?

Yes—if we design it. We ensure continuous soffit intake and ridge exhaust, add baffles where insulation blocks pathways, and select ridge vents that won’t whistle. Ventilation protects sheathing, stabilizes temperature, and helps the assembly stay quiet. ( nrca.net [7])

Is standing seam better than stamped metal shingles for a recover?

Depends on slope and geometry. Standing seam excels on simple or low-slope planes (with the right profile). Stamped shingles shine on complex, steep roofs where modularity reduces waste and improves fit. Both can be recovered when documentation allows. standing seam vs shingles Vancouver

Will my warranty be valid over shingles?

Yes—when the system is installed exactly per manufacturer instructions for recover, including underlayment, fasteners, slopes, and details. Keep all documentation. Local standards for sheet metal detailing (flashings, closures) strengthen long-term serviceability and warranty comfort. ( rpm.rcabc.org [3])

Is a batten (vented) system worth it?

Often, yes—especially if the shingle surface isn’t perfectly flat or you want enhanced drying under the metal. Battens add an air channel and decouple the panel from old ridges, but they demand meticulous eave/rake closures to block pests and wind.

How long will a metal-over-shingle roof last here?

With PVDF-finished panels, concealed clips, correct underlayment, and annual maintenance, you’re aiming at the same multi-decade lifespan as a conventional metal install. The overlay doesn’t shorten life when the base is dry, flat, and ventilated as designed.

Author and credentials

Written by Harman, Roofer, Paragon Roofing BC (Vancouver).

I specify, install, and inspect metal systems across Metro Vancouver’s wet, windy microclimates. My guidance balances code, manufacturer instructions, and building science so homeowners buy once—and enjoy the roof for decades. Credentials: https://www.paragonroofingbc.ca/

References (accessed Aug 17, 2025)

• Vancouver Building By-law — Division B, Section 9.26 Roofing (materials/installation per manufacturer): https://vancouver.ca/files/cov/vbbl-2019.pdf (see current hosted extract) and official extract: https://free.bcpublications.ca/.../vbbl2019/1005507067. ( BC Publications [2])
• RCABC — Standard for Architectural Sheet Metal (ASM) Systems (detailing, flashings, practices): https://rpm.rcabc.org/.../ASM_Systems.pdf. ( rpm.rcabc.org [3])
• Metal Construction Association — White Paper: Retrofitting Existing Roofing with Metal (direct-to-deck vs over-purlin methods): https://www.metalconstruction.org/.../retrofitting-existing-roofing-with-metal. ( metalconstruction.org [4])
• IBHS — Roof Guide: Codes & Standards (recover vs replacement overview): https://ibhs.org/.../roof-guide-codes-and-standards/. ( ibhs.org [1])
• City of Vancouver — When you need a permit (project-scope guidance): https://vancouver.ca/.../when-you-need-a-permit.aspx. ( City of Vancouver [6])

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