A dormer is a room poking its head through the roof. Gable dormers wear a little peaked roof; shed dormers carry a single sloped plane; either way the payoff is real daylight and standing room in an upstairs or attic space. The cost of that charm lives in the joints: every dormer adds two sidewalls needing step flashing, roof junctions that may form valleys, a front wall over the roof plane, and lower corners that want kick-out flashing. One dormer can double the number of flashing details on that side of the roof.
Why dormers matter in Douglas County
Joints are where roofs leak, and our climate stress-tests every one of them — roughly 130 rain days a year, with winter storms driving water sideways into wall junctions. The shaded pockets beside a dormer also dry slowly and grow moss early. When we inspect the classic older two-stories around Roseburg and Oakland, dormer flashing is checked first, because that's where the ceiling stains usually trace back to.
When it fails, what it costs you
Dormer leaks are sneaky: water enters at a sidewall or valley, tracks along framing, and stains a ceiling somewhere else entirely. The repair itself — re-flashing a sidewall, re-lining a valley — is routine roof repair money; the drywall, insulation, and window-trim rot from years of slow seepage is where it gets expensive. Thinking of adding a dormer for space and light? That's a framing-to-flashing project our general contracting side handles end to end.
Why do dormers leak more than the rest of the roof?
Concentration of joints. A plain roof plane has almost no seams; a dormer packs sidewalls, corners, a roof-to-roof junction, and window trim into a few feet — each one a detail that has to be flashed exactly right to survive an Oregon winter.