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Home | Our Blog | Gambrel Roofs: Pros, Cons, Installation Guide

Gambrel Roofs: Pros, Cons, Installation Guide

Reviewed by Tomas Kalkys. President.
Qualifications: More than 20 years of experience in residential and commercial exterior remodeling.
Founding farther of Legacy Service.
Written by LegacyUSA Team

posted on Nov 10, 2020

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Gambrel Roofs

Gambrel roofs are most often used on barns and sheds. This style is best described as a two-sided, symmetrical roof that has two slopes on each side. The upper slope is shallow, while the lower slope is steeper. They were called “Dutch roofs” in eighteenth-century England and North America.

In this article, we’re going to review the pros and cons of the gambrel roof style and provide an installation guide if you’re looking to install or replace it. At Legacy Service, we offer all types of home exterior services, from roof replacement to siding installation. Contact us today to schedule a free consultation.

What is a Gambrel Roof?

The easiest way to picture a gambrel roof is by thinking of a barn. Most barns use gambrel roofs because they’re simple to build and have a classic look. They can be best described as a two-sided, symmetrical roof with two slopes on each side. The upper slope will usually be more shallow while the lower slope is typically steeper. They’re somewhat similar to mansard roofs except for the fact that mansard roofs have four sides.

If you’re interested in building this type of roof on your property, continue reading this article. We’ll discuss how they’re built, the advantages and disadvantages, as well as different variations and prices.

History of Gambrel Roofs

While it’s not known how or when gambrel roofs originated in North America, the oldest example of one is on the second Harvard Hall at Harvard University of America, which was built in 1677. The oldest house with a gambrel roof in the United States also dates back to 1677-1678. The standard design was found on many Dutch colonial houses. Dutch traders were inspired by the style and brought it with them when they traveled to other parts of the world. Houses with gambrel roofs are less common now but they are still used with other types of buildings, especially barns and sheds.

Gambrel Roofs Built

How are Gambrel Roofs Built?

Gambrel roofs need to be framed out by the builder, so they will build out a series of individual trusses that have identical measurements. How many gambrel roof trusses you’ll need will depend on the size of the roof. You can do this by assembling wooden boards on a flat surface. Each side of the truss has two beams that are reinforced with a gusset plate. When the trusses are complete, they’re raised into place on top of the building.

We’ll review a step-by-step process for building gambrel roofs in one of the sections below. So if you’re looking for a more detailed description, please continue reading.

How Long Do These Roofs Last?

The lifespan of a gambrel roof will depend on a number of factors, including but not limited to the area’s climate, the roof’s design, the materials needed, the installation process, and the amount and quality of maintenance the roof receives. For example, a roof that’s covered by a durable material like metal and installed by a professional can last up to a century. Roofs covered with other materials like wood or asphalt will have a much shorter lifespan, averaging about 15-25 years.

In the next sections, we’ll go over the gambrel roof advantages and disadvantages.

Advantages

There are plenty of advantages to choosing a gambrel roof design for your house, barn, or shed. They include:

  • Classic appearance – Most gambrel roofs look like they belong in colonial America. This classic look was popular on Georgian and Dutch style homes throughout the United States.
  • Easy to install – Compared to other types of roofing styles, gambrel is comparatively easy to design and install. Involving the use of gussets in the process helps simplify the process.
  • Affordable cost – Since this style has such a simple design, fewer resources are required. It not only saves time and labor, but it also helps reduce installation and maintenance costs.
  • Provides plenty of space – With gambrel roof proportions, especially the lower steep slopes, you’ll find that there’s plenty of room for extra storage and headspace. Remember that they require a proper roof vent system during installation to allow for more barn roof ventilation.

Disadvantages

Why do some property owners opt for other types of roofs instead? The disadvantages include:

  • Not suitable for all climates – Depending on where you live and the climate of your area, a gambrel roof might not be best for your building. They tend to struggle in extreme rainfall as well as heavy winds and snow.
  • Low durability – Even with proper installation and waterproofing methods, gambrel roofs require plenty of maintenance and care due to low durability. It’s also important to schedule annual inspections to check for damage.

Variations of Gambrel Roofs

Variations of Gambrel Roofs

Gambrel roofs are available in a variety of styles. Three of the most popular variations include:

  • Classic style – This is currently the most common style in the United States. It’s typically seen on sheds and barns. You can also maximize the attic space using a two-pitch design.
  • Wall-supported style – Although this design provides a stylish look, it’s not the best type for those who would like to maximize their storage space. Since the lowest part of the pitch overhangs the house’s eaves, storage space is limited.
  • Mansard style – This is also known as the French roof, since so many buildings in France use it. This style has pitches of different sizes.

Other types include gable, dormer, and valley gambrel.

Price of Gambrel Roofs (Cost of Materials and Installation)

While the price of gambrel roofs will vary depending on the place you live, the type of building you’re covering, and the materials you choose, we’ll talk about the average prices in this section. For example, you can expect to pay about $8-$14 for framing materials and labor per square foot. This would equal to about $16,000 to $28,000 for a 2,000 square foot area roof.

Roofing materials (including asphalt shingles, wood, metal, and slate) can cost anywhere from $4 to $20 per square foot.

How to Build a Gambrel Roof: Installation Guide

It’s usually best to hire professionals to install any type of roof, but gambrel roofs are actually simple to install if you’re looking to do it yourself. Just make sure to do your research beforehand, so you can gather all of the items and materials and know exactly which steps to take before you get started. Check out our installation guide below to get a better idea of how to proceed with your project.

Materials

The materials you’ll need to build a gambrel roof include:

  • Wood trusses
  • ½” plywood
  • ¾” plywood
  • Waterproof material
  • Roofing material of your choice (asphalt shingles, wood, metal, etc.)

Tools

The tools you’ll need to install a gambrel roof include:

  • Calculator
  • Ruler
  • Tape measure
  • Chalk or pencil
  • Saw
  • Speed square
  • Hammer
  • Nails

Preparation

Gambrel roof preparation involves cutting the rafter pieces. First, you’ll need to purchase 2×4 wooden boards. Determine how many you’ll need and buy a few extra in case you make a mistake while cutting. Then, use a pencil to mark the ends of the boards on a 22.5 degree angle. Use a circular saw to cut the boards along the line you just made.

Step-by-Step Guide

So, how do you install a gambrel roof? Here are the steps you should take to build your new roof:

  1. Determine how tall you want your roof to be.
  2. Figure out how many trusses you’ll need and how long each should be to cover your building. It’s recommended to place the trusses 16 inches apart from each other.
  3. Buy the trusses you’ll need (along with a few extra, just in case).
  4. Lay four of them out on a flat surface and use chalk or a pencil to mark the angles of the two upper and two lower trusses.
  5. Use a saw to cut them to the correct angles. Then, use them as the templates for the rest of your trusses.
  6. Create gusset plates to hold your trusses together.
  7. Make sure the first truss fits the building’s dimensions and secure your trusses with brackets.
  8. Raise the first truss into position. Nail it to the joists of the lower floor.
  9. Put a brace between your first truss and the next to make sure they remain sturdy.
  10. Continue to attach gambrel roof trusses.
  11. After you’re finished, cover the structure with ¾” plywood and secure it.
  12. Place a layer of waterproof material over the plywood, and install the gambrel roof shingles of your choice.

Frequently Asked Questions

Here are the questions that we’re most frequently asked about gambrel roofs:

Where are gambrel roofs most common?

Although they can be used for houses, gambrel roofs are most commonly found on sheds and barns throughout the United States. During the 18th century in England and America, they were used for Dutch colonial houses. Just looking at them will show you why they’re so popular for these types of buildings. They’re easy to install, provide plenty of storage space, and offer a classic look since they have two slopes on each side.

Why do barns have gambrel roofs?

When you think of this type of roof, you’re most likely thinking of the roof on top of a barn. Barns use gambrel roofs for a variety of reasons. As we previously mentioned, they’re easy to install, are cost-effective, have a classic look, and provide plenty of space. These roofs are known for being functional rather than stylish, which is perfect for barns.

What are the angles for a gambrel roof?

Gambrel roofs are symmetrical two-sided roofs, with two slopes on each side. The lower slope is positioned at a steep angle while the upper slope tends to be more shallow. For a standard gambrel roof, the peak is built at a 30-degree angle with the second slope at 60 degrees. If you’d prefer something else, gambrel roof angles can be customized according to what works best for your building.

What is the difference between a gambrel roof and a mansard roof?

Gambrel roofs and mansard roofs are fairly similar in construction and appearance. The main difference is the fact that mansard roofs have four sides while gambrel roofs only have two.

Other differences include:

  • Mansard is hipped at the four corners of the building while gambrel has vertical gable ends.
  • A mansard typically doesn’t overhang the facade, while a gambrel does.

How do you attach gambrel roof trusses?

Gambrel roofs are typically assembled on the ground and then installed in sections. After you cut the trusses to the correct angles, create gusset plates from ½” plywood to hold the trusses together. Then, you can join the trusses together and attach the brackets using a hammer and nails. Once you make sure the first truss fits the building’s dimensions, you can continue to secure the trusses together with brackets.

How do you measure for a gambrel roof?

To frame out a gambrel roof, the builder will need to construct a series of individual trusses that have equal measurements. Start by purchasing 2×4 boards for the rafters. Use a pencil to mark both ends of the boards on a 22.5-degree angle. Then, cut along the lines you make using a circular saw or miter. Once that’s done, you can start assembling the rafters.

Installing Your Gambrel Roof

Get Started Installing Your Gambrel Roof Today!

If you’ve made it this far, then you must be interested in installing a gambrel roof for a building you own, whether it’s your home, a barn, or a shed. So, let’s get started! Our team at Legacy Service provides roofing installation and replacement services for homeowners throughout areas in southeastern Pennsylvania, New Jersey, and Delaware. We also provide siding installation and window replacement services for those in need. Call us at 215-798-9790 or contact us here to learn more.

Posted on Nov 10, 2020 in Roof

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