Everything About Gambrel Roofs (Types, Advantages & More)

The type of roof your home has can be a unique architectural feature that sets it apart from other houses in the area. Some roof structures can even significantly increase property value. With that said, whether you’re updating your existing roof or looking for a new design, it is very beneficially to opt for a structure that is appealing.

A gambrel roof, also known as a “Dutch roof,” is a two-sided gable roof with symmetrical slopes on either side with its highest peak averaging at a 30-degree angle. The different types include the classic, mansard, and wall-support gambrel roofs. They provide excellent drainage, lots of space, and are cost-effective to build but require maintenance.

Often seen as the stereotypical roof on farm houses, barns, sheds, and log cabins, a gambrel roof can offer additional floor space and a nostalgic appearance. However, these types of roofs aren’t just for these types of structures. In fact, gambrel roofs are gaining popularity among homeowners who seek a bigger and more functional attic space.

In this guide on gambrel roofs, we will explore every aspect of this roof design including its history, the advantages and disadvantages, and how to build a DIY gambrel roof for your property.

A gambrel roof is essentially a type of symmetrical two-sided gable roof that has two slopes on either side. The upper slope is positioned at a shallow angle, while the lower slope is much steeper – almost vertical. A gambrel roof’s peak is typically constructed at a 30-degree angle and the second slope is usually 60 degrees.

However, these roofs can be customized to the individual desires of the builder or homeowner. The design of a gambrel roof offers the benefits of a sloped roof while reducing what would otherwise be a tall roof and maximizing usable space in the building’s upper level.

When used on homes or residential buildings, gambrel roofs most often include double-hung windows, for extra natural light, and a dormer. A dormer is an additional space that protrudes out from the building with its own roof parallel to the larger roof.

Gambrel roofs are a standard design for Dutch colonial homes, and was made popular in the 18th century in North America. The roof structure of barns are probably the most notable examples of gambrel roofs.

The word “gambrel” is Norman English and has many different spellings, including “gambol” which can be found in the Boston carpenters’ price book from 1774. It refers to a wooden bar that is used by butchers to hang the bodies of slaughtered animals.

When in use, a butcher’s gambrel, which was later constructed out of metal, resembled the two-sloped design of a gambrel roof. Hence, the reason for the designation as a “gambrel roof.” With that said, the origin of gambrel roofs in North America is generally unknown. However, the oldest gambrel roof in American can be found at Harvard University – The second Harvard Hall built in 1677. Arguably, the oldest surviving home in the United States with a gambrel roof is the Peter Tufts House, a Colonial American home in Massachusetts, circa 1677-1678.

The gambrel roof style is very common across Georgia, Maine, and even more so in Coastal regions across the country. It was popularized in North American during the 18th century, and was also referred to as a “Dutch roof” during this time. Some historians believe that early Dutch traders in Southeast Asia saw the style and brought it with them to other places they traveled to.

Some view this roof design as modest, however, there is no denying its ability to survive several thousands of years of home styles. While the original gambrels provided more living spaces on a third story, modern versions are typically more popular due to their visual interest.

Initially, a gambrel roof is framed out. This means that the builder will construct a series of individual trusses, all with identical measurements. These trusses can be achieved by using wooden two by four boards that are either assembled on the ground or another flat surface.

On a gambrel roof, each side of the roof truss has two roof beams, which are reinforced using a gusset place. A gusset plate is simply a metal or wooden plate that helps to strengthen the joint, and is generally screwed in to secure. Once all of the trusses are built, they are raised into position on top of the structure. Then, they are secured to the floor.

Afterwards, the trusses are covered with the deck of the roof, which can be made of shingles, wood, or metal siding. The number of trusses that are required depends entirely on the size of the building and the size of the roof being built.

Once you’ve developed a plan for your gambrel roof, you’ll need to buy some 2×4 boards to assemble your rafters. To determine how many boards you need, count your wall studs. You need one full rafter piece for each wall stud and each rafter piece is going to consist of 4 2×4 boards that are 4 feet long.

With that said, if you have 5 wall studs, you’re going to need 5 full rafters. Since you need 4 boards per rafter, that means you’ll need to buy a total of 20 boards. However, you’ll want to get extra boards just in case!

Once you have your boards, mark both ends of each at a 22.5 angle and cut along those lines. You can use either a circular saw or a miter saw. When you’re done cutting, all of the board ends should sit flush against each other.

Using a piece of 10 feet by 5 feet plywood as the dimensions of your roof, start to assemble the rafter pieces. Place them flat onto the piece of plywood so that they are lined up with all the ends flush. This is how the rafters should appear when installed on your shed.

Then, to help you connect rafter pieces together, you can install wood blocks on either side which will keep them in place. The next step is to create the gussets, which are used to reinforce the joints. This can be achieved by nailing 1.5 inches of plywood at all the joints. Repeat this process for the remaining rafters.

The final step is to hoist the rafters onto the top of your structure. You may want to enlist the help of some friends for this stage in the process. Raise the rafters into position so that they line up flush with the wall studs.

Then, place a metal plate between the rafter and the top of the wall. Drive nails through the board at an angle that goes through both the rafter board and the top of the wall. A joint place should be installed on each side of the rafter boards. Continue installing a rafter for each wall stud.

Last but not least, measure and cut 4 total pieces of plywood or thick OSB. These will be your roof sheeting and should be the width of each piece of rafter and roughly half the length of the structure. Starting at the top corners, nail the sheeting into place.