Metal Roofing in Duncan

Moss needs something to hold onto. An asphalt shingle's rough surface holds moisture, letting Cowichan Valley roofs grow moss faster than Victoria roofs that receive roughly half our rainfall. A smooth metal panel gives moss nothing to grip and sheds water before it can sit, so the maintenance interval that asphalt needs largely disappears.

Forty to seventy years for metal against fifteen to thirty for asphalt comes down to one thing: asphalt fails from sustained wetting, and metal does not. On heavily treed lots toward Sahtlam or Lake Cowichan where shingles need frequent treatment, a metal roof lowers your lifetime ownership costs and gives your home lasting protection.

Standing-seam panels are held by concealed clips, with the seam raised above the water plane and no fastener penetrating the weather surface. Exposed-fastener profiles are screwed through the panel face into the strapping, each screw sealed by a neoprene washer. Those washers set the lifespan of the system — they harden, shrink and work loose, and in sustained coastal wet a twenty-year-old exposed-fastener roof is usually a re-screwing project.

Standing seam costs more and gives back a roof with no gaskets in the water path. It also handles thermal movement better on long runs, which matters on south-facing slopes here. Exposed-fastener panel still earns its place on outbuildings, shops and simple low-value roofs where the price gap is the deciding factor. Either way, the flashing at chimneys, skylights and wall junctions is the part we spend most time on.

We lay high-temp underlayment over the entire deck surface first. Long metal panels lock together along vertical seams using hidden clips and fasteners. The clips allow panels to expand and contract naturally as weather temperatures change. Exposed screws are avoided along main panel runs. Continuous ridge caps and custom wall flashings seal the high points and wall joints tightly.