Green Roofing vs. Clerestory Roofing: Which One Is Right for You?

No one can play down the role of roofing in the aesthetics, energy efficiency, and overall functionality of a building. As homeowners and architects seek innovative solutions, green and clerestory roofs have become popular roofing choices. Both roofing types offer distinct advantages: Green roofs promote sustainability and energy conservation. In contrast, clerestory roofs maximize natural light and ventilation. But which one is best for your needs?

In this article, we will break down the pros, cons, costs, maintenance needs, and best use cases of both roofing options, helping you make an informed decision. Are you ready? Let’s go!

What is Green Roofing?

From the name “green roofing,” one may guess it involves green plants. Others may think that it has something to do with the roof being the color green.  Well, if your guess was the former, you are absolutely right! 

A green roof is any roof covered with vegetation, soil, and drainage layers supporting plant life. The designs of this kind of roof depend on factors like the climate, proposed usage, access, slope, and the structure’s capacity. Hence, they are specific to the siting. A significant selling point of green roofs is their natural ability to reduce heat absorption and promote energy efficiency.

Types of Green Roofing

There are three major types of green roofs, each of which varies in terms of vegetation, depth of the growing medium, and maintenance requirements. Understanding these differences is crucial when considering which green roof system best suits a particular building or environment.

Extensive Green Roofs

Extensive green roofs are the most common green roofs due to their lightweight structure and minimal upkeep. They typically feature a thin layer of soil, about 2–6 inches. Experts design them to support hardy, low-growing vegetation such as sedums, mosses, and drought-resistant grasses. 

They have several benefits, including low maintenance, cost-effectiveness, excellent insulation, and stormwater absorption. However, they do not have the capacity to deal with heavy foot traffic. You will typically find them on residential homes, commercial buildings, and structures with weight limitations.

Semi-Intensive Green Roofs

This roof type offers a middle ground between extensive and intensive systems. With a soil depth ranging from 6 to 12 inches, they give room for a wider selection of plants, including grasses, shrubs, and small flowers. Although they need moderate maintenance, they have a better aesthetic appeal and improved biodiversity than extensive green roofs. They are ideal for corporate spaces, urban buildings, and educational institutions that want greenery without excessive upkeep. 

The benefits of semi-intensive green roofs include enhanced biodiversity, better air quality, and encouragement of plant diversity. The downside of this kind of green roof is that it requires occasional irrigation and maintenance and is slightly heavier than the extensive kind.

Intensive Green Roofs

Intensive green roofs are essentially rooftop gardens that can support a variety of deep-rooted plants, shrubs, and even trees. With a soil depth of 12 inches or more, these green roofs require regular maintenance, irrigation, and structural support due to their weight. 

They often feature walkways, benches, and recreational areas, transforming rooftops into functional green spaces. Intensive green roofs come with limitations, too. They are expensive to install and maintain; they require significant structural reinforcement.

What is Clerestory Roofing?

A clerestory roof is a roof design that has a vertical wall that rises above the main roof. The vertical walls have windows or openings, including a row of high windows (clerestory windows) to bring in natural light and improve ventilation. 

Typically, installers place the window above eye level to let in sunlight while maintaining privacy. A clerestory roof primarily admits natural light, or air in some cases, into a room.  This is particularly true for large rooms with interior walls far from the exterior ones. 

Types of Clerestory Roofs

Clerestory roofs come in various designs, primarily categorized as symmetrical or asymmetrical, each offering unique aesthetic and functional benefits.

Symmetrical Clerestory Roofs

These roofs feature balanced slopes on either side of the clerestory windows, creating a harmonious and uniform appearance. Common symmetrical clerestory roof types include:

• Gable clerestory roof: This is a traditional gable roof with a raised central section containing a row of windows. This design allows natural light to penetrate the interior deeply while maintaining a classic architectural look.
• Hip clerestory roof: It is similar to a gable clerestory roof but with sloping sides on all four sides. This design provides enhanced stability and wind resistance, making it ideal for regions with harsh weather conditions.

Asymmetrical Clerestory Roofs

These designs feature an uneven slope, with one side extending higher than the other, usually resembling a skillion or shed roof. Asymmetrical clerestory roofs include:

• Skillion clerestory roof: Another name for this type is Shed roof. It consists of a single sloping plane with a vertical clerestory window section separating different levels. You typically find it in modern, minimalist architecture for its sleek, energy-efficient design.
• Sawtooth clerestory roof: This roof consists of skillion-like slopes with vertical clerestory windows in between. This industrial-inspired design maximizes daylight while reducing glare, making it ideal for factories, workshops, and contemporary homes.

Regardless of the design, clerestory roofs enhance natural ventilation, improve interior illumination, and contribute to a building’s energy efficiency, making them a popular choice for residential and commercial structures.

Comparing Green Roofing vs. Clerestory Roofing

Both roofing styles offer eco-friendly advantages, with green roofs focusing on insulation and environmental impact. In contrast, clerestory roofs enhance daylighting and ventilation.

Impact of Green Roofing on the Environment

Green roofs are more than just aesthetically pleasing. They actively improve urban environments in several ways:

• Air purification: The vegetation on green roofs filters pollutants, improving overall air quality.
• Stormwater management: Green roofs absorb rainwater, reducing the risk of flooding and the pressure on drainage systems.
• Urban heat reduction: Green roofs lower surrounding temperatures by minimizing heat absorption, making cities more livable.
• Wildlife habitat: These roofs provide essential green spaces for birds, insects, and other small creatures, enhancing biodiversity.

Benefits of Clerestory Windows: Energy Efficiency

• Maximizes natural daylight: Reduces electricity consumption by allowing more sunlight into interior spaces.
• Enhances passive cooling: Warm air naturally rises and escapes through clerestory windows, improving indoor comfort.
• Improves indoor air quality: Increased airflow helps reduce humidity and promotes better ventilation.

Installation and Maintenance Expectations 

Green Roof Installation Step

1. Reinforce the roof structure to support the weight of soil and vegetation.
2. Apply waterproofing and root barriers to prevent leaks.
3. Install a drainage system to manage excess rainwater.
4. Add soil and plant the desired vegetation.

Green Roofing Maintenance Routine

1. Water the vegetation, prune it, and fertilize it regularly.
2. Observe routine inspection for leaks and drainage efficiency.

Clerestory Roof Installation Steps

1. Position windows strategically for optimal sunlight exposure.
2. Use double-glazed or tinted glass to enhance insulation.
3. Ensure proper framing to support the window structure.

Clerestory Roofing Maintenance Routine

1. Clean the windows occasionally to remove dust and maintain clarity.
2. Inspect the windows for air leaks or heat loss to ensure energy efficiency.

Which Roofing Option is More Budget-Friendly?

Green roofing requires a higher initial investment due to structural reinforcement and waterproofing. However, it reduces heating and cooling costs in the long run, offering long-term savings.

Clerestory roofs, on the other hand, have varying costs, depending on the type and window placement. Additionally, maintenance costs are lower than those of green roofs.

Green roofs can yield substantial energy savings over time but require ongoing maintenance. Clerestory roofs lower lighting costs but must be well-insulated to prevent energy loss.

Which Roofing Type Is Right For You?

Green roof is ideal if:

• You prioritize sustainability and insulation.
• You live in an urban environment with limited access to green spaces.
• You want to reduce rainwater runoff and improve air quality.

Clerestory roof is ideal if:

• You prefer modern aesthetics with ample natural light.
• You want passive cooling and energy efficiency.
• You live in a mild or warm climate where ventilation is crucial.

Conclusion

Both green and clerestory roofs offer significant advantages, but the best choice depends on your needs, climate, and budget. Green roofs provide excellent insulation, environmental benefits, and urban greenery, while clerestory roofs enhance natural lighting, ventilation, and energy efficiency.

Before making a final decision, consulting with an expert can help you determine the best fit for your home or building. With the right approach, your roofing choice can contribute to a greener, more energy-efficient future.

Frequently Asked Questions

What are the three types of green roofing?

Experts categorize green roofs into intensive, semi-intensive, and extensive green roofs. Intensive green roofs include parks and gardens, semi-intensive include garden green roofs, and extensive include natural low-maintenance green roofs.

How long do green roofs last?

Many green roofs have a life expectancy of about 30-50 years, giving them a lifespan that is superior to a couple of other roofing options.