What you're working with: hip roofs and dormer intersections
A hip roof slopes on all four sides, which means every edge is a ridge or hip line rather than a gable end. When dormers break through that surface, you create valleys where the dormer roof meets the main roof — these are the places water wants to pool and leak. Shingling this configuration means working in a specific order: main roof first, then dormer roofs, then the valleys where they meet. The valleys are where most mistakes happen, so that's where most of your attention goes.
With four dormers, you're managing four separate valley systems. Each one needs the same treatment, but you'll install them one at a time. The work is slower than a straightforward roof because you can't run shingles in straight lines across the whole surface — you have to stop, cut, and redirect at each valley.
Key Takeaways
- Install shingles on the main roof first, running them up to where each dormer valley begins, then cut them to fit the valley angle.
- Valleys need valley flashing (metal or rolled roofing) installed before any shingles go down, and shingles must be cut at 45 degrees to follow the valley line.
- Dormer roofs are shingled after the main roof, and their shingles overlap the main roof shingles at the lower edge of each dormer roof.
- The order matters: main roof → valley flashing → main roof shingles trimmed at valleys → dormer roofs → final valley shingle cuts and nailing.
- Each valley requires careful measurement and a sharp utility knife; a single miscut valley can channel water into the attic.
Preparing the roof deck and installing valley flashing
Before any shingles go down, the roof deck must be clean and the valleys must have flashing. Start by sweeping the entire roof surface and checking that all plywood is find and dry. If you're working over an existing roof, you may be tearing off old shingles first — if so, remove them completely and inspect the deck for rot or soft spots.
Valley flashing comes in two forms: metal (aluminum or galvanized steel) or rolled roofing (a tar-based product). Metal lasts longer but costs more; rolled roofing is cheaper and easier to cut. For a hip roof with dormers, most roofers use metal because water moves faster through valleys and you want it to drain quickly. Measure each valley from the peak down to where it meets the eave, add 2 feet, and cut your flashing to that length. Nail the flashing down the center of the valley with roofing nails every 12 inches, alternating sides so the nails don't create a straight line that can leak. Leave the edges of the flashing exposed — shingles will cover them later.
If you're using rolled roofing instead, unroll it down the valley, nail it the same way, and make sure the seams overlap by at least 6 inches if you need more than one piece.
Shingling the main roof up to the valleys
Start at the eave of the main roof, below all dormers. Snap a chalk line 11 inches up from the eave (this accounts for the 5-inch exposure of standard shingles plus the overhang). Nail your starter course along this line — this is a row of shingles with the tabs cut off, placed upside down. This gives the first course of visible shingles something to sit on and keeps water from running under them.
Lay your first course of shingles right-side up, starting at one corner and working across. Each shingle overlaps the one below it by 5 inches. Nail four nails per shingle, placed in a line about 1 inch above the cutouts. When you reach a valley, don't try to bend the shingle around it — stop before the valley and cut the shingle at a 45-degree angle so it points down into the valley. The cut edge should be about 2 inches away from the valley centerline on each side. This gap prevents water from being forced under the shingles by wind.
Continue this pattern up the main roof, row by row, cutting shingles at each valley as you go. Stagger the seams so that the cutouts don't line up vertically — offset each row by half a shingle width. When you reach the hip lines (the edges where the roof slopes down on all four sides), cut shingles to follow the hip angle and nail them so they don't curl up in the wind.
Installing dormer roofs and their shingles
Once the main roof is shingled up to all four valleys, move to the dormer roofs. Each dormer has its own small roof that slopes down toward the main roof. Start at the peak of each dormer and work down, using the same starter course and 5-inch overlap method. Nail carefully — dormer roofs are small and it's straightforward to split the plywood if you nail too close to an edge.
When you reach the lower edge of each dormer roof (the edge that meets the main roof), your dormer shingles will overlap the main roof shingles you already installed. This overlap is correct — it directs water down and out, not under. Nail the dormer shingles so they sit flat against the main roof shingles. Don't nail through both layers into the deck; nail only through the dormer shingles into the dormer roof deck.
After all four dormer roofs are shingled, you'll have gaps where the dormer roof edges meet the valleys. These gaps are where the final valley shingles go.
Cutting and installing final valley shingles
The valleys now have flashing and are partially covered by main roof shingles on one side and dormer roof shingles on the other. The remaining exposed flashing needs to be covered with shingles cut to fit the valley angle. These are the most critical cuts on the job.
Measure the width of the exposed flashing at the top of each valley and at the bottom. It will be wider at the bottom because the valley angle opens up. Cut shingles to fit this trapezoid shape — the top edge will be narrower than the bottom. Use a utility knife and a straightedge, and make the cut on the back side of the shingle so you can see your line clearly. A sharp blade is essential; a dull blade will tear the shingle and create a weak spot.
Nail these valley shingles down with four nails, placed well away from the cut edges. The cut edges should be at least 1 inch from any nail. This prevents the nails from splitting the shingle or creating a path for water to enter. Once all four valleys are covered, the roof is complete.
Common mistakes and how to avoid them
The most common error is cutting valley shingles too close to the centerline of the valley. This leaves no margin for error and allows water to run under the shingles during heavy rain or wind-driven rain. Always leave at least 2 inches of clearance on each side of the valley centerline. The second mistake is nailing too close to cut edges — nails near a cut edge can split the shingle or create a leak path. Keep all nails at least 1 inch from any cut.
A third mistake is not staggering seams on the main roof. If cutouts line up vertically, water can follow the seam down and pool at the valley. Offset each row by half a shingle width. Finally, some roofers skip the starter course or install it incorrectly. The starter course is not decorative — it's a water barrier. Install it upside down, nail it securely, and make sure it covers the entire eave.
Tools and materials you'll need
You'll need a roofing hammer or pneumatic nailer, a utility knife with extra blades, a chalk line, a straightedge or speed square, a tape measure, and a ladder or roof brackets for safety. For materials, stock standard asphalt shingles (25-year or 30-year grade), roofing nails (1.25 inches for standard shingles), valley flashing (metal or rolled roofing), and roofing cement or sealant. Buy 10 percent more shingles than your square footage suggests — waste is higher on a roof with dormers because of all the cuts.
If you're working on a steep roof or one higher than 20 feet, rent or buy roof brackets and safety harnesses. A fall from a hip roof with dormers is more likely than from a straightforward roof because the surface is broken up and your footing is less stable.
Frequently Asked Questions
Do I have to tear off the old shingles before installing new ones?
Most building codes allow one layer of new shingles over one layer of old shingles, but not more. If there are already two layers, you must tear off to the deck. Even with one old layer, tearing off lets you inspect the deck for rot and gives you a cleaner surface to work on. The extra labor is worth it on a complex roof like this one.
What's the difference between metal and rolled roofing for valleys?
Metal flashing lasts 20+ years and handles water faster, but costs more and requires more precision when cutting. Rolled roofing costs less and is easier to cut, but may need replacement in 10–15 years. For a roof with four dormers, metal is the better choice because valleys are high-stress areas and you want them to last as long as the shingles do.
Can I shingle a hip roof with dormers alone, or do I need a helper?
You can do it alone, but a helper makes the work safer and faster. A second person can hand you materials, hold the straightedge while you cut, and spot you on the ladder. On a roof this complex, having someone on the ground watching for mistakes is valuable.
How long does it take to shingle a hip roof with four dormers?
Time depends on roof size and your experience. A typical 1,500-square-foot main roof with four small dormers takes 3–5 days for one experienced roofer, or 2–3 days with a helper. If you're new to roofing, add 50 percent to that estimate.
What do I do if I cut a valley shingle wrong?
Remove the nails, pull out the bad shingle, and cut a new one. Don't try to patch it or nail it down anyway — a bad cut in a valley will leak. Shingles are cheap; water damage is expensive. Keep extra shingles on hand for this reason.