If you haven’t guessed already, we’re interested in all things roofing here at Digital Roofing Company, and Japanese roofs are one in particular that has caught our eye. Japanese roofs are steeped in culture and architecture. Features such as the materials used, the shape of the roof, and its connection with nature are all things Japanese architects have considered for centuries. We’ll talk you through the nine unique features of Japanese roofs.  

9 Unique Features Of Japanese Roofs

• Roofing Materials

• What Are Japanese Roofs Called

• Basic Roof Forms

• Roof Trusses

• Kirizuma

• Yosemune

• Irimoya

• Hogyo

• Relationship With Nature

• Why Are Japanese Roofs Curved

• What Are Traditional Japanese Roofs Made Of

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Roofing Materials 

Here in the United States, it’s common to see roofs made of asphalt shingles. In Japan, on the other hand, most of their roofs are made of wood. This is because Japan sits on the Ring of Fire which means that they are at high risk of being hit by earthquakes.

Having a wood roof means that if the building comes down, the impact if it were to hit someone, is smaller than if someone was crushed by asphalt or brick. Many of Japan’s traditional temples use wood because of its ability to absorb moisture, which allows them to build a building without using nails – meaning they’re safer and more resistant against strong earthquakes. 

When you travel around Japan, you’ll notice that the wood they use for their buildings hasn’t been covered by paint. This is because the Japanese appreciate the wood they use for its durability, sturdiness and natural smell. The scent provides a relaxing environment in the home and is proven to kill bacteria. All good things when building a home. 

What Are Japanese Roofs Called

Although Japan is synonymous with technology and modern architecture, a big part of Japanese culture is the intersection between modern and traditional architecture. Japanese roofs are a unique feature of Japan’s traditional architecture, and we’ll talk about each type more as we make our way through this article. 

However, there are four main types of Japanese roofs. Kirizuma, Yosemune, Irimoya, and Hogyo. Each of these has distinctive characteristics, and once you understand them, you’ll be able to spot them a mile away. 

Basic Roof Forms

Japanese roofs aren’t just built to look and smell nice. The eaves of the roofs are designed to protect the windows from rain, a staple in Japanese summer. Rain doesn’t stop the Japanese from keeping their windows open to let in a fresh breeze. They can open their windows for fresh air even while it’s pouring down outside because of their roof structure. How neat! 

Roof Trusses

Most Japanese roofs are made of wood and are built on a truss framework which supports the roof, floor, and the whole house. This means that the roof isn’t just part of the top of the house but forms part of the structure of the entire building. 

A roof truss is a “wood structure that integrates a triangular webbing of structural members to provide support for the roof above while tying the outside walls of the house together.”

Kirizuma

Now to the different Japanese roofs. The Kirizuma is the oldest roof style, with two sides connected by a ridge. It’s the most straightforward Japanese roof style, and you’ll often notice it in lower socio-economic areas, townhouses and shrines. 

Yosemune

The Yosemune is a form of Japanese roof that has four sloping faces. It is the second most widely-used form of a roof in Japan and was originally most common in eastern Japan. With two triangle-shaped roofs at “tsumagawa” and two trapezoid-shaped roofs at “hiragawa”, the side parallel to the “omune”. 

Having a four-way sloping roof means that it’s made well to handle heavy rain as it drains well. The downside is that because there’s no vertical plane, these roofs tend to lead to bad ventilation, which is why this roof style is often combined with other roof forms to make a complex, but functional shape. 

Irimoya

This is a stunning example of a combination of roof forms. The Irimoya combines the hipped and the gable roofs, which gives the building the stability it needs but can also withstand heavy snow. This makes it great in areas that see proper weather shifts and will ensure that you’ll be kept safe and warm. 

Hogyo

We’ve talked about angled roofs, but the Hogyo takes things further by being square. This is a roof type that’s common in the Buddhist temples that you see dotted around Japan. You’ll be able to point it out because, at the top of the roof of a temple, a parallelepipedic object with spiritual significance called a roban is installed. This roban is said to ward off evil spirits, which is fitting for a religious building. 

Relationship With Nature

As you may have already learned, a lot of Japanese culture, even when it comes to their roofs, is connected with their respect for nature. Even in their architecture, they strive to work in harmony with their natural surroundings. 

For example, they use roof angles that optimise airflow or raw materials instead of manufactured ones. Because of this, many architects looking to create sustainable designs look to Japan for inspiration, as Japanese roofs have been using sustainable methods for generations. 

Why Are Japanese Roofs Curved

Many Japanese roofs are curved because they commonly believe evil spirits hate curves and would fall off the roof due to the angle of the roof. This is not only a common roof structure in Japan but also in China. 

What Are Traditional Japanese Roofs Made Of

Japanese roofs traditionally use natural materials like cypress bark (hiwada), shingles (kokera), and thatch (kaya). Many of the heritage buildings in Japan will have hand-cut shingles of cypress or cedar overlaid each other to cover the roof. 

Now that you’re an expert in Japanese roofs, do you understand why we’re so interested in them here at the Digital Roofing Company? It’s now time to book your flight and see them in person. You won’t regret it. 

From the Kirizuma to the Hogya, these roofing structures have been designed with purpose and sustainability in mind. Using materials that are sourced from nature, Japanese roofs take inspiration from the environment around them to make sure the structures are built to fit their surroundings. 

You won’t find a roof structure in Japan that’s made for summer conditions in an area known for heavy rain and snow. These are all things that make these roofs a wonder to explore.