A mansard roof has a steep, near-vertical lower slope on every side and a low-pitched or nearly flat top, so the roof itself forms the walls of a usable top floor. King Roof Care, a locally owned roofer, offers roof repair, replacement and inspection for homeowners in Kirkland, Bothell, Everett, Issaquah and Redmond, WA, starting with a free, no-obligation roof assessment.
What Type of Roof Is a Mansard Roof?
A mansard roof is a roof style with a steep lower slope on every side of the building and a much shallower upper section that is often close to flat. From the street, the steep part reads almost like a wall covered in roofing, and the shallow top is often barely visible.
- Straight mansard: flat, steep lower slopes with a crisp, boxy outline
- Convex or bell-cast mansard: lower slopes that curve outward near the eaves
- Concave mansard: lower slopes that curve inward for a softer silhouette
- Mansard with dormers: windows framed into the steep sides, each with its own flashing details
Mansard Roof Compared With Gable, Hip, Gambrel and Flat Roofs
Mansard roof design is easiest to understand next to the other common residential roof shapes, because each shape changes where water travels and which details need the most attention.
| Roof style | Basic shape | What it means for upkeep |
|---|---|---|
| Gable | Slopes meet at a central ridge, with triangular wall sections at the ends | Simple lines; the exposed end walls and rake edges need attention |
| Hip | Slopes on every side rise to a ridge or a point | More hips and ridges to cap and seal |
| Gambrel | Steep lower slope and shallow upper slope on the front and back only | A break line to flash on the long sides, plus gable ends |
| Mansard | Steep lower slope and shallow upper slope on every side | A continuous break line all around; the low-slope top needs a material suited to low slopes |
| Flat or low-slope | Nearly level surface | Usually membrane systems; drainage and ponding water matter most |
Mansard Roof Pros and Cons for Homeowners
Mansard roof pros and cons come down to a trade between living space and complexity. The style adds a usable top floor and a distinctive look, but it also stacks steep-slope and low-slope roofing on the same house, with a long transition line between them.
| Pros | Cons |
|---|---|
| Near full-height living space on the top floor | More transitions and flashing details than a simple gable roof |
| Steep sides leave room for dormer windows | The shallow top drains slowly and needs a material suited to low slopes |
| Distinctive, formal appearance | Steep sides are hard to walk, so repairs call for careful access |
| Lower visible roofline than a tall pitched roof over the same floor | A full replacement can involve both steep-slope and low-slope materials in one job |
Roofing Materials for a Mansard Roof's Steep Sides and Low-Slope Top
Mansard roof material choices usually split into two decisions: one for the steep lower slopes and one for the shallow top. Each roofing product has a slope range and fastening method set by its manufacturer, so the material on the sides is often different from the material on the top.
| Mansard roof area | Materials King Roof Care works with that may fit | What to confirm before choosing |
|---|---|---|
| Steep lower slopes | Composition and asphalt shingles, presidential shingles, wood shakes, metal | Manufacturer's approved slope range and fastening for steep application |
| Low-slope or near-flat top | PVC and single-ply membrane systems, or metal systems the manufacturer rates for low slopes | Drainage path, any ponding, and how seams are handled at the curb |
| Curb or break line | Flashing tied into both materials | How the steep-slope material and the low-slope material overlap so water sheds outward |
Where Mansard Roofs Leak and What a Roof Inspection Checks
Mansard roof leaks tend to show up where materials, slopes or surfaces change, so a careful inspection focuses on transitions rather than only the open roof field.
- The curb or break line where the steep sides meet the shallow top
- Flashing around each dormer, including the cheeks and the head of the window
- Wall-to-roof joints where the steep slope meets trim or siding
- Gutters at the base of the steep slopes, which collect fast-moving runoff
- Ponding or membrane wear on the low-slope top
- Chimneys, vents and skylights that pass through either section
- Signs of sagging in the steep sides that may point to structural repair
How a Mansard Roof Replacement Moves From Assessment to Cleanup
Mansard roof replacement with King Roof Care follows the company's documented roof replacement sequence; the steps below are its general process, and the details specific to a mansard are written into the estimate for that home.
- On-site inspection of the roof, the attic and the ventilation, noting anything that affects the work
- Written estimate with the exact scope and materials before any work starts
- Tear-off and haul-away of the existing roofing material
- Inspection of the roof deck, with damaged sheathing replaced as needed
- New underlayment, plus ice-and-water protection where the roof requires it
- Flashing at valleys, walls, chimneys and other roof penetrations
- Starter course, new roofing and ridge caps
- Full cleanup once the work is done
Mansard Roof Estimate Checklist and Mistakes That Cause Rework
Mansard roof estimates are harder to compare than estimates for a plain gable roof, because two roof systems and a long transition line hide inside one price. Asking the same questions of every contractor makes the quotes comparable.
Checking the contractor is part of the comparison. King Roof Care is a registered Washington construction contractor, L&I registration KINGRRC782QA, which can be verified with the Washington L&I verify tool, and it is rated 4.9 out of 5 on Google (as of 2026-11-02). If a mansard needs targeted work rather than a full roof, the company's roof repair service covers leak detection and flashing repair.
- Which material is specified for the steep sides, and which for the low-slope top?
- How will the curb or break line be flashed so water sheds outward?
- How will each dormer be flashed, and is that flashing new or reused?
- Does the scope include deck inspection and replacement of damaged sheathing?
- Where will underlayment and ice-and-water protection go?
- Are gutters at the base of the steep slopes included or checked?
- Is tear-off, haul-away and cleanup included in the written scope?
- Can the contractor's Washington L&I registration be verified?