Roof pitch (or slope) describes how steep a roof is, written as rise over run: a 4/12 roof climbs 4 inches vertically for every 12 inches it travels horizontally; a 12/12 roof climbs at a full 45 degrees. That one ratio quietly controls a lot — which materials are allowed, how fast water leaves the roof, how safe it is to walk, and how much surface area (and therefore money) a reroof involves per roofing square.
Steep pitch or low-slope roof? We're set up for every pitch in Douglas County. Serving Roseburg, Riddle & all of Douglas County.
Why pitch matters in wet Douglas County
With 30–33 inches of rain falling across our long October-to-May wet season, drainage speed is not academic. Steeper planes shed water and fir-needle debris quickly and dry faster after storms, which is why steep roofs around Roseburg carry noticeably less moss than shallow ones. Shallower pitches hold water longer, collect debris in valleys, and give moss its foothold. Material rules follow pitch too: standard shingles want 4/12 or steeper; between 2/12 and 4/12 they need special low-slope installation; below 2/12 you're into membrane or metal territory — see low-slope roof.
When pitch is ignored, what it costs you
The classic mistake is shingling a too-shallow porch or addition roof like the main house. It looks fine for a year or two, then wind-driven rain creeps uphill under the shingles and rots the decking. If part of your roof is shallow and leaking, that's a job for someone who knows the low-slope rules — start with our roof repair page. Pitch also drives winter safety: walking a wet, steep Oregon roof is genuinely dangerous, one more reason we push ground-level checks in our winter roofing guide.
How do I find my roof's pitch?
From a ladder at the gable end, hold a level horizontally against the rake and measure the rise over a 12-inch run. Phone apps get close too. Or ask us — we measure it as part of any free estimate.
Related terms
Low-slope roof · Roofing square · Valley · Rake · Dormer