12 Roof Plan Ideas

A roof plan is not a floor plan. It is an aerial view of the roof—showing slopes, ridges, valleys, hips, dormers, chimneys, skylights, and drainage. Unlike a floor plan, which shows interior spaces, a roof plan shows how water flows off the building. The roof plan is the primary drawing for roof framing, waterproofing, and gutter installation. The challenge is balancing aesthetics (the roof is the fifth facade) with function (water must drain, snow must not accumulate, and the structure must stand).

1. The Gable Roof (Two Slopes, Triangular Ends)

A roof with two sloping planes that meet at a central ridge, forming a triangular gable at each end. The gable roof is the most common roof type in residential construction. The slope ratio is typically 6:12 to 12:12 (rise in inches per 12 inches of run). The gable roof sheds water efficiently and provides attic space. The challenge is that the gable ends are vulnerable to high winds.

This roof is for houses, cottages, or any building requiring a simple, traditional roof. The emotional effect is triangular, traditional, and gabled.

Quick Specs

• Slope: 6:12 to 12:12 (26° to 45°).
• Ridge length: equals building length.
• Overhang: 0.3-0.6m (rake and eave).
• Gable ends: triangular walls (often with windows or vents).

2. The Hip Roof (Four Slopes, No Gables)

A roof with four sloping planes that meet at a ridge at the top. All sides slope downward. There are no gable ends—the roof wraps around the entire building. The hip roof is more stable than a gable roof in high winds. The challenge is more complex framing (hip rafters and jack rafters). The slope ratio is typically 4:12 to 8:12.

This roof is for houses in windy or hurricane-prone regions, or any building requiring a stable, all-around roof. The emotional effect is hipped, pyramidal, and stable.

Quick Specs

• Slope: 4:12 to 8:12 (18° to 34°).
• Ridge length: shorter than building length (hips at ends).
• Hip lines: diagonal lines from ridge corners to eaves corners.
• Eaves: continuous overhang on all four sides.

3. The Flat Roof (Nearly Horizontal, Parapet or No Parapet)

A roof with a slope of 0.25:12 to 2:12 (1° to 9°). The roof is nearly flat but must slope slightly for drainage. Water drains to internal drains (through the roof) or to scuppers (through the parapet). The flat roof is common in commercial and modernist residential buildings. It can be used as a roof terrace or green roof. The challenge is waterproofing (flat roofs leak more than sloped roofs) and ponding water.

This roof is for modern houses, commercial buildings, or any building with a roof terrace. The emotional effect is flat, horizontal, and modern.

Quick Specs

• Slope: 0.25:12 to 2:12 (minimum 1% for drainage).
• Drainage: internal drains or scuppers (every 15-20m).
• Parapet: 0.3-1.0m high (if present).
• Roof terrace: accessible (with railing if over 0.6m high).

4. The Shed Roof (Single Slope, Lean-To)

A roof with a single sloping plane. One wall is higher than the opposite wall. The shed roof is the simplest roof to frame (rafters all the same length). It is often used for additions, porches, or modern houses. The slope is typically 3:12 to 8:12. The high side faces the sun (for solar panels) or the view. The challenge is that the low side can feel cramped (low ceiling height).

This roof is for modern houses, additions, or any building where a single slope is desired. The emotional effect is shed-like, lean-to, and modern.

Quick Specs

• Slope: 3:12 to 8:12 (14° to 34°).
• High wall height: 3-5m (depending on building depth).
• Low wall height: 2-2.5m (minimum for headroom).
• Overhang: on all four sides (or on the low side only).

5. The Mansard Roof (Two Slopes on Each Side, Double-Pitched)

A roof with two slopes on each side: a lower slope (steep, 18:12 to 24:12) and an upper slope (shallow, 4:12 to 8:12). The lower slope is often hidden behind a parapet or contains dormer windows. The mansard roof creates an additional habitable floor in the attic (the steep lower slope allows full-height walls). This roof is characteristic of French Second Empire architecture (19th century).

This roof is for traditional houses, historical renovations, or any building requiring additional floor area in the roof. The emotional effect is mansarded, double-pitched, and French.

Quick Specs

• Lower slope: 18:12 to 24:12 (56° to 63°) (steep).
• Upper slope: 4:12 to 8:12 (18° to 34°) (shallow).
• Lower slope height: 1.5-2.5m (to allow windows).
• Dormers: often present on the lower slope.

6. The Gambrel Roof (Two Slopes on Each Side, Barn-Like)

A roof with two slopes on each side: a lower slope (steep, 12:12 to 18:12) and an upper slope (shallow, 4:12 to 8:12). Unlike a mansard roof, the gambrel roof has gable ends (not hipped). The gambrel roof is characteristic of Dutch colonial and barn architecture. It creates a large, open attic space (the steep lower slope allows full-height walls). The challenge is complex framing (knee walls, purlins).

This roof is for barns, Dutch colonial houses, or any building requiring a large attic. The emotional effect is gambreled, barn-like, and Dutch.

Quick Specs

• Lower slope: 12:12 to 18:12 (45° to 56°).
• Upper slope: 4:12 to 8:12 (18° to 34°).
• Ridge: runs the full length (gable ends).
• Attic space: full-height (knee walls at the lower slope).

7. The Butterfly Roof (Inverted Gable, V-Shaped)

A roof with two sloping planes that slope inward toward a central valley (an inverted gable). The low point is at the center; the high points are at the two exterior walls. The butterfly roof collects water in the center (requiring a central drain or scupper). This roof is characteristic of mid-century modern architecture (1940s-1960s). The challenge is drainage (water collects in the valley) and snow load (snow collects in the valley).

This roof is for modern houses, mid-century modern renovations, or any building requiring a dramatic, V-shaped roof. The emotional effect is butterfly, V-shaped, and mid-century.

Quick Specs

• Slope: 4:12 to 8:12 (18° to 34°) (inward).
• Valley: at the center (lowest point).
• Drainage: central drain or scuppers at the valley.
• High walls: at the two exterior walls (north and south).

8. The Pyramid Roof (Square Base, Four Slopes, Central Peak)

A hip roof on a square building, where all four sloping planes meet at a single point (a peak, not a ridge). The pyramid roof is a special case of the hip roof. It is common on gazebos, pavilions, and square houses. The slope is typically 6:12 to 12:12. The challenge is the central peak (all rafters meet at one point).

This roof is for square buildings, gazebos, or any building requiring a pyramidal form. The emotional effect is pyramidal, Egyptian, and central-peaked.

Quick Specs

• Building footprint: square (equal length and width).
• Slope: 6:12 to 12:12 (26° to 45°).
• Peak: at the center of the square.
• Hip lines: diagonal from the peak to each corner.

9. The Dome Roof (Curved, Hemispherical or Segmental)

A roof that is curved in two directions (double-curvature). The dome can be a hemisphere (half a sphere) or a segment (shallower than a hemisphere). Domes are common on mosques, observatories, and capitol buildings. Residential domes are rare but possible with monocoque construction (sprayed concrete) or geodesic framing (Buckminster Fuller). The challenge is complex formwork and waterproofing.

This roof is for observatories, mosques, capitol buildings, or any building requiring a monumental, curved roof. The emotional effect is domed, curved, and monumental.

Quick Specs

• Base diameter: 6-20m (residential scale).
• Rise: 1/2 to 1/3 of the diameter (hemisphere = rise = 1/2 diameter).
• Oculus: optional opening at the top (circle).
• Framing: geodesic (triangles) or monocoque (concrete).

10. The Green Roof (Vegetated, Planted)

A roof covered with vegetation and growing medium. The green roof plan shows the drainage layer, growing medium depth, and planting zones (sedums, grasses, shrubs, or trees). The green roof can be extensive (shallow soil, 50-150mm, sedums and mosses) or intensive (deep soil, 200-500mm, shrubs and trees). The plan must show roof drains (to prevent ponding) and access for maintenance.

This roof is for flat or low-slope roofs, urban buildings, or any building requiring stormwater management. The emotional effect is planted, green, and ecological.

Quick Specs

• Growing medium depth: 50-150mm (extensive) or 200-500mm (intensive).
• Drainage layer: 20-40mm (gravel or dimpled membrane).
• Slope: 1-2% (for drainage).
• Planting zones: labeled (sedum, grass, shrubs, trees).

11. The Solar Roof (Photovoltaic Panels Integrated)

A roof designed for solar photovoltaic (PV) panels. The solar roof plan shows the orientation (south-facing in the northern hemisphere), slope (15-40 degrees optimal), panel layout (rows and columns), inverter location, and electrical conduit. The panels can be roof-mounted (on top of existing roofing) or building-integrated (BIPV, panels are the roofing material). The plan must show shading obstacles (chimneys, trees, vents).

This roof is for houses, commercial buildings, or any building seeking net-zero energy. The emotional effect is solar, paneled, and energy-generating.

Quick Specs

• Orientation: south-facing (in northern hemisphere).
• Slope: 15-40° (optimal for latitude).
• Panel size: 1.0m x 1.7m (typical).
• Panel spacing: 0.01-0.05m (gap for expansion).
• Inverter location: near the electrical panel (garage or basement).

12. The Folded Plate Roof (Angular, Faceted, Origami-Like)

A roof made of flat, angular planes that fold like origami. The folded plate roof is a modern, sculptural roof type. It is often made of reinforced concrete or steel. The folds create a dramatic interior space (the ceiling follows the folds). The roof is self-bracing (the folds provide structural stiffness). The challenge is complex formwork and detailing at the fold lines.

This roof is for modern houses, pavilions, or any building requiring a dramatic, faceted roof. The emotional effect is folded, faceted, and sculptural.

Quick Specs

• Fold angles: 30-60° between adjacent planes.
• Plane shape: triangles or trapezoids.
• Material: reinforced concrete (cast-in-place) or steel.
• Drainage: water flows to valleys (low points).

Comparison Summary

Conclusion

The roof plan is the fifth facade—the view most people never see, but the one that matters most for weather protection, energy performance, and structural stability. Unlike the other four facades (north, south, east, west), the roof must also work: it must shed water, resist wind, support snow, and (in many climates) provide insulation and ventilation.

The twelve roof plans presented here offer different strategies for different climates, budgets, and aesthetics:

The Gable Roof says: simple, traditional, and efficient. The gable roof is the standard for a reason—it works, it’s easy to build, and it provides attic space. The only drawback is wind vulnerability at the gable ends.

The Hip Roof says: stability in wind. The hip roof wraps around the building, eliminating vulnerable gable ends. The trade-off is more complex framing and less attic space.

The Flat Roof says: use the roof as a terrace. The flat roof is the only roof type that can be occupied (with proper railings and waterproofing). The trade-off is the risk of leaks and ponding water.

The Shed Roof says: simplicity and solar orientation. The shed roof is the easiest to frame (all rafters the same length). The high side can face the sun for solar panels. The trade-off is a cramped low side.

The Mansard Roof says: add a full floor in the attic. The steep lower slope allows dormer windows and full-height walls. The trade-off is complex framing and a distinctly historical look.

The Gambrel Roof says: barn-like charm and attic space. The gambrel roof is simpler than a mansard (gable ends, not hipped). The trade-off is a distinctly rural or Dutch colonial aesthetic.

The Butterfly Roof says: mid-century modern drama. The inverted V-shape is instantly recognizable. The trade-off is drainage (water collects in the valley) and snow load (snow collects in the valley).

The Pyramid Roof says: monumental simplicity on a square building. The pyramid roof is a special case of the hip roof. The trade-off is the central peak (all rafters meet at one point).

The Dome Roof says: curved, monumental, and strong. The dome is the most structurally efficient shape for spanning large spaces. The trade-off is complex formwork and waterproofing.

The Green Roof says: ecology and stormwater management. The green roof absorbs rain, insulates the building, and provides habitat. The trade-off is weight (saturated soil is heavy) and maintenance.

The Solar Roof says: generate your own electricity. The solar roof is not a roof shape but a roof treatment. The trade-off is orientation (south-facing required) and shading (no trees or chimneys).

The Folded Plate Roof says: sculptural and self-bracing. The folded plate roof is for clients who want a dramatic, modern roof. The trade-off is complex formwork and high cost.

When designing a roof plan, ask: Where does the water go? All roofs must drain. Gable and hip roofs drain to eaves. Flat roofs drain to internal drains or scuppers. Butterfly roofs drain to a central valley. If water ponds, the roof will leak.

Ask: Where does the snow go? In snowy climates, steep roofs (8:12 or steeper) shed snow. Shallow roofs (4:12 or less) hold snow, requiring structural reinforcement. Flat roofs in snowy climates are rare (except with heated membranes).

Ask: What is the attic used for? If the attic is storage or living space, the roof must be framed with trusses or rafters that allow headroom. Gable, hip, mansard, and gambrel roofs provide attic space. Flat and shed roofs do not.

Ask: What is the view from above? The roof plan is the fifth facade. If the building is visible from above (from a hill, a taller building, or an airplane), the roof should be designed as a composition—not just a functional surface.

Ask: How is the roof ventilated? In cold climates, attic ventilation prevents ice dams and moisture buildup. Ridge vents, soffit vents, and gable vents must be shown on the roof plan.

The best roof plan is not the one with the most dramatic shape. It is the one that keeps the interior dry, stands up to the wind, sheds snow before it accumulates, and looks like it belongs on the building. It is the umbrella that never lets you down.