Metal roofing · Corrugated and ribbed
Exposed-fastener and corrugated metal roofing
Exposed-fastener panels are the classic rural metal roof: corrugated or ribbed steel sheets, cut to length, screwed through the face into purlins or a deck with colour-matched gasketed screws. They are the fastest and cheapest metal roof to install and the right answer for most farm buildings, shops, equipment sheds and detached garages. On a house they work too, with a few honest caveats about fasteners and slope.
- Lifespan
- 30 to 50 years, with fastener checks
- Gauge
- 26 ga for most buildings, 29 ga on budget farm roofs, 24 ga available
- Finish
- SMP (silicone-modified polyester) or PVDF
- Fasteners
- colour-matched screws with EPDM washers
Panels from BC and Canadian manufacturers such as Westform Metals, Vicwest, Fraser Valley Metal Rolling, Agway Metals.
Strengths
What it does well
- The lowest-cost metal roof, often close to premium shingles
- Fast: large panels go on in a day or two
- Goes over open purlins, no plywood needed on outbuildings
- Classic Rib and corrugated profiles stocked locally and cut to length
- Class A fire rating
Trade-offs
What to weigh up
- Thousands of screws in the weather: gaskets age and screws back out over 15 to 25 years
- Side and end laps can wick water on low slopes
- Thinner steel (26 or 29 ga) dents more easily
- Needs a steeper slope than standing seam, usually 3:12 and up
- Condensation drips on open-framed buildings without a vapour barrier or anti-drip coating
In our climate
Right for the valley's outbuildings
From Langley and Abbotsford out to Chilliwack and Agassiz, the farm roof is a ribbed steel panel on wood purlins, and for good reason: it is cheap, light, fire-safe and goes up fast between weather. Where it fails is at the screws. Every one is a hole, every gasket ages, and a roof with a few thousand of them needs a walk-over every few years to re-drive and replace what has loosened. Budget 29 gauge dents in hail and under ladders; 26 gauge is worth the difference on anything you care about.
On a house we build it differently: solid deck, synthetic underlayment, proper eave and gable trim, and we talk you through fastener maintenance before you sign. On a low slope or a roof you never want to think about again, standing seam is the better buy.
Price
Priced for your roof
Pitch, shape, what comes off and how we reach the roof all move the price, so every roof is measured before we quote. For a number now, outline yours on the satellite map.
Specification
- Profiles
- Classic Rib (7/8 in rib), corrugated, box rib
- Steel
- 26 or 29 gauge Galvalume
- Screws
- every 24 in at purlins, in the flat or on the rib per the manufacturer
- Closures
- foam at ridge and eave
- Over purlins or a solid deck with underlayment
Questions
Exposed-fastener and corrugated panels questions
How often do the screws need checking?
Plan a walk-over every eight to ten years, sooner on a roof that gets sun all day. Screws back out as the panel expands and contracts and the rubber washers harden. Re-driving loose screws and replacing stripped ones with the next size up keeps the roof tight for decades.
Is 29 gauge good enough?
For a budget farm roof over purlins, it is what most of the valley uses. For anything you care about, 26 gauge costs a little more and resists dents from hail, ladders and foot traffic much better. On a house we use 26 or 24.
Why does my shop roof drip inside when it is not raining?
Condensation. Warm humid air inside meets a cold panel on a clear night and water forms on the underside. The fix is airflow at the ridge and eaves, a vapour barrier under the purlins, or panels with a factory anti-drip fleece. We specify one of these on every open-framed building.
Compare
Other metal systems
Standing seam metal roofing
Lasts 40 to 70 years
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Metal shingles and tiles
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Aluminum, copper and zinc roofing
Lasts 50 to 100+ years
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New construction and additions
Metal roofs and siding on new houses, laneway homes, garages, shops, barns and additions, coordinated with your builder from the framing stage.
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Metal roof repair
Leaks at flashings and penetrations, backed-out screws, failed sealant, storm damage and rust spots on existing metal roofs of any make.
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Gutters, soffit, fascia and flashing
Seamless aluminum gutters, metal soffit and fascia, and custom-bent flashings that match the roof, so the whole edge of the house is metal.
See details →Guides
How much does a metal roof cost in BC's Lower Mainland?
Metal roof prices in Metro Vancouver and the Fraser Valley in 2026: standing seam, metal shingles and corrugated per sq ft, whole-roof budgets and extras.
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Metal roof maintenance and repair: screws, sealant, rust and the yearly check
How to look after a metal roof in BC: the yearly walk-around, fastener checks on screw-down roofs, what sealant to use and never use, and when to call.
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Are metal roofs noisy in the rain? What the research says
Rain noise on metal roofs measured: about 6 decibels over shingles on a solid deck, louder on open framing. What makes the difference and how to quiet a shop.
Read →Thinking about corrugated and ribbed?
Free in-person measure, written quote, no pressure after.