How to Build a Gambrel Roof

Have you ever run across a gambrel roof? They’re used on barns and in houses and pretty much look like a U. A gambrel roof is really just a U-shaped roof whose ends have been raised up on the sides. Why does it look like this? Well, it was to keep livestock in the roofed areas of barns. Apparently farmers knew that cows weren’t real fans of heights, so by raising the end of the roof, they would prevent cows from jumping up onto the top of it.

Gambrel roofs have a distinct look and are often seen on barns. They are similar to gable roofs but feature an asymmetrical slope. One side is steeper than the other, gambrel roof angles gambrel roof truss gambrel roof overhang and in most cases, the gables extend to the ground for an extra layer of protection from weather elements. This project will show you how to build a gambrel roof with common power tools.

Gambrel Roof

🏠 What Is a Gambrel Roof?

• A gambrel roof (also called Dutch roof) is a two-sided roof with two slopes on each side: a steeper lower slope and a shallower upper slope—though some can have more than two sections
• It has vertical gable ends, unlike a mansard, which is hipped

📚 Historical Origins

• The term “gambrel” stems from Medieval Latin gamba (horse’s hock), referencing its shape.
• It may have originated from European tradesmen (Dutch, French, German) or even indigenous Pacific Northwest designs.
• The oldest known American gambrel roofs date back to Harvard Hall (1677) and the Peter Tufts House (circa 1677–78).

➕ Advantages

• Maximizes upper-level space—creates roomy lofts, attics, or haylofts .
• Classic, charming aesthetic that suits barns, homes, cottages.
• Flexible material options (shingles, metal, slate) b.
• Offers good insulation and ventilation thanks to ample attic space

➖ Drawbacks

• More complex and costly to build vs. simple gable roofs
• Vulnerable to wind uplift and snow accumulation on shallow upper slopes.
• Requires frequent inspection and maintenance .
• Not suited for all architectural designs—may look out of place on some home styles

🌍 Geographic and Architectural Use

• Became widespread in colonial New England, especially in Dutch Colonial styles across New York, Pennsylvania, and Vermont
• A hallmark of Dutch Colonial Revival in the early 20th century, notable for flared eaves on long sides

Feature	Description
Definition	A **gambrel roof** is a two-sided sloping roof that features two upwardly curved sides, with the upper slope being steeper than the lower slope.
Slope Ratio	The lower slope of a gambrel roof typically measures about 2/3 of the height of the upper slope.
Applications	Gambrel roofs can be utilized in a variety of building types including: Barns: Frequently seen in agricultural structures, barns with gambrel roofs allow for maximum storage space in the loft area. Sheds: The design provides effective rain runoff while maintaining aesthetic appeal. Homes: Residential architecture often embraces gambrel roofs for their charm and maximizing attic space. Other Buildings: Suitable for various types of buildings like garages and recreational structures.
Advantages	Some advantages of gambrel roofs include: Increased Space: The design allows for a loft area, perfect for storage or living space. Efficient Water Drainage: The sloping sides promote effective drainage, reducing water accumulation. Aesthetic Appeal: A gambrel roof adds character and charm to a building’s appearance. Cost-Effective: Uses less material compared to traditional gable roofs, impacting building costs positively.
Considerations	Important considerations when selecting a gambrel roof include: Snow Load: The design must consider how snow accumulation will affect the roof’s stability. Material Selection: Choose materials that can handle the stresses of the sloping design. Local Regulations: Ensure compliance with building codes and zoning laws. Maintenance: Consider the long-term maintenance requirements for a roof with such angles.

Gambrel Roof Angles

🧩 Comparison: Gambrel vs Others

• Vs. Gable: Gambrel gives more headroom in attic versus gable’s simpler, less spacious design .
• Vs. Mansard: Both double‑sloped, but mansard covers four sides, gambrel only two
• Vs. Hip: Gambrel is less wind-resistant and self-bracing compared to tightly interconnected hip roofs

📐 Variations & Usage

• Multiple styles: classic straight, bell‑cast eaves (flared), cross-gambrel, wall‑supported
• Often used on barns, sheds, homes—“barn roof” gambrel.
• In the West, “prairie barns” adopted gambrel for hay storage in the 19th century

Gambrel roof overhang

A gambrel roof is a double-pitched roof, with a steeply pitched lower section and a shallow upper section. The steep lower slope of the roof is called the “crotch”, and it typically runs at an angle of 25 to 35 degrees from vertical. The shallow upper slope is called the “pan”.

The pitch of the roof may be expressed in degrees (as above), or by the ratio of the rise over the run. A one to one ratio between pitch and run would be described as a “1 in 1” roof, which has no pitch; a two to one ratio would be described as a “2 in 1” roof, which has 50% pitch. A 3:12 pitch would be described as having a 45 degree angle.

A gambrel roof is usually seen on barns and farmhouses in North America, but also appears on many other types of buildings such as fire stations, schools, churches and other public buildings where long spans are required.

✅ Summary

A gambrel roof offers practical storage and living space, classic charm, and design flexibility. However, it requires careful design, quality materials, and upkeep—especially in windy or snowy climates. If you’re planning one, think about space, weather, cost, and style fit.