Roofing services · Duncan
Roof Repair in Duncan
Leaks traced to the actual source, not the nearest stain — flashing, valleys, storm damage and lifted shingles, with the cause documented in photos before anything is patched.
Roof repair across Duncan, North Cowichan and Lake Cowichan most often traces back to flashing rather than shingles — chimney and skylight penetrations, open valleys, and step flashing at wall junctions. Duncan receives roughly 1,500 mm of precipitation a year, with November alone averaging over 200 mm, so a small opening moves a large volume of water in a single storm. Most Cowichan Valley repairs fall between $500 and $3,000, and a repair is worth doing when the surrounding shingles still have meaningful service life left.
A ceiling stain almost never sits under the hole. Water enters at a penetration or a valley, travels along the underside of the sheathing or down a rafter, and shows up in a different room. Repairs that start with the stain instead of the source get repeated the following winter, which is why every repair here begins with finding the entry point and photographing it.
Where Cowichan Valley roofs actually leak
Flashing is the recurring answer. Chimney counter-flashing that has pulled from the mortar joint, skylight head flashing installed without a diverter, and step flashing along a wall junction that was face-nailed instead of woven into the courses. All three fail slowly, and all three release water directly into the assembly rather than onto the shingle surface above.
Valleys come second. Under heavy tree cover toward Sahtlam, Glenora and Lake Cowichan, Douglas fir and cedar needles pack a valley solid over one autumn. Water backs up under the course above the valley metal and runs sideways into the deck. Clearing valleys is maintenance; replacing a section of rotted sheathing under one is not.
Then wind. Southeast systems come across the valley through the winter and lift the seal strip on aging shingles. A shingle that has broken its seal will still look intact from the ground and will let water past on the next driving rain.
Repair or replace
The deciding factor is remaining service life in the surrounding field, not the size of the damage. Asphalt shingles are rated 15 to 30 years, so a flashing failure on a twelve-year-old roof is a repair, and the same failure on a twenty-six-year-old roof with granule loss and curling edges is money spent twice.
An honest assessment names which one applies and why, with photos of the deck condition and shingle wear rather than a verdict. Where a roof is genuinely mid-life, a targeted repair plus a maintenance interval is the cheaper path by a wide margin. Where the field is spent, the cost guide sets out what full replacement looks like across the Cowichan Valley.
Typical price range
$500 – $3,000
Most repairs fall between $500 and $3,000 depending on access, the number of failure points and how much sheathing is affected. Roofs found to be past useful life are quoted as replacement instead, with the reason shown in writing.
Serving nearby communities
Keep exploring
- Compare roof costsWhat a re-roof, a repair and a metal system actually cost in the Cowichan Valley, with the variables that move each figure.
- Roof ReplacementFull asphalt re-roofs in Duncan and the Cowichan Valley — tear-off, deck inspection, new underlayment and code-rated venting. Typically $8,000–$20,000, quoted on site.
- Roof MaintenanceRoof moss treatment, gutter and valley clearing and sealant renewal in Duncan and the Cowichan Valley. Typically $300–$1,200 — the work that gets a roof to its rated life.
- Cowichan Roofing home
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Serving Duncan, North Cowichan, Lake Cowichan and Cowichan Bay across the Cowichan Valley Regional District.