libterm.com Curtain walls are non-structural outer coverings of buildings designed to protect against weather and enhance aesthetic appeal while allowing natural light. These lightweight, durable systems are often made from glass, aluminum, or other materials that provide thermal insulation and noise reduction. Discover how curtain walls improve your building's performance and design by reading the full article.
Table of Comparison
| Feature | Curtain Wall | Breast Wall |
|---|---|---|
| Definition | Exterior facade system made of glass or metal panels attached to the structure | Low protective wall at balcony or roof edge, usually masonry or concrete |
| Function | Provides weather resistance, insulation, and aesthetic facade | Safety barrier and wind shield |
| Structural Role | Non-load bearing, supported by building frame | Load-bearing element supporting parapet or railing |
| Material | Glass, aluminum, steel, composite panels | Concrete, brick, stone, or masonry |
| Installation | Prefabricated units assembled on site | Built in-situ with masonry or concrete |
| Typical Use | Commercial and high-rise buildings facade | Balconies, rooftops, terraces |
| Thermal Performance | High insulation with thermal breaks | Minimal thermal performance |
| Maintenance | Regular cleaning, sealant and gasket replacement | Occasional repainting or repairs |
| Cost | Higher due to materials and technology | Lower; simpler construction |
Introduction to Curtain Walls and Breast Walls
Curtain walls are non-structural outer coverings typically made of glass, aluminum, or metal frames that protect buildings from weather while allowing natural light inside. Breast walls, also known as knee walls, are short walls usually found between the floor and window sill or roof, providing support and acting as a barrier. While curtain walls emphasize aesthetic and environmental control in modern architecture, breast walls primarily enhance structural stability and indoor comfort.
Definition and Functions of Curtain Walls
Curtain walls are non-structural outer coverings of buildings designed to resist air and water infiltration while allowing natural light and views, typically made of glass, metal, or lightweight materials. They function as weather barriers and contribute to thermal insulation without supporting the building's structural load. In contrast, breast walls are low walls or parapets that provide support or act as barriers but do not serve the extensive enclosure or environmental protection roles of curtain walls.
Definition and Functions of Breast Walls
A breast wall is a low protective wall built along the edge of a roof, terrace, or balcony to prevent falls and provide safety. Unlike curtain walls, which are non-structural outer coverings of buildings designed primarily for aesthetic appeal and weather resistance, breast walls serve a structural safety function. Breast walls also help in supporting railings and can act as barriers against wind and debris, enhancing both security and comfort in elevated outdoor spaces.
Key Differences Between Curtain Walls and Breast Walls
Curtain walls are non-load-bearing exterior facades designed to resist environmental forces and provide aesthetic appeal, typically composed of glass, metal, or lightweight materials. Breast walls, also known as knee walls, are short masonry or framed walls that partially support roof or floor loads and are often found in basement or attic areas. The key differences lie in function--curtain walls act as protective outer skins without structural support, while breast walls contribute to structural stability and load distribution within a building.
Structural Roles in Building Design
Curtain walls serve as non-load-bearing exterior cladding systems designed to resist environmental forces while allowing natural light penetration, supporting the building's envelope without carrying structural loads from floors or roofs. Breast walls, on the other hand, are low, load-bearing walls typically constructed between structural columns or beneath windows, providing support to the superstructure and transferring loads to the foundation. Emphasizing their distinct structural roles, curtain walls enhance facade aesthetics and weatherproofing, whereas breast walls contribute to overall building stability by bearing vertical loads.
Material Selection and Construction Techniques
Curtain walls typically utilize lightweight materials such as aluminum frames with glass panels, emphasizing prefabrication and modular assembly to enhance speed and precision in high-rise construction. Breast walls, commonly constructed with masonry or concrete, rely on traditional on-site building techniques that involve reinforced concrete forms or brick laying for durability and load-bearing capacity. Material selection for curtain walls prioritizes thermal performance and aesthetic transparency, while breast walls focus on structural robustness and insulation efficiency.
Aesthetic and Architectural Considerations
Curtain walls provide sleek, modern aesthetics through their glass and aluminum framing, allowing for maximum natural light and uninterrupted exterior views that enhance building transparency and elegance. Breast walls, typically solid and constructed from masonry or concrete, create a grounded, robust appearance that offers a strong architectural base, often emphasizing texture and materiality for visual interest. Both elements impact building aesthetics by balancing light, transparency, and solidity, influencing the overall style and architectural expression.
Durability, Maintenance, and Lifespan
Curtain walls, typically made from aluminum frames and glass panels, offer high durability and low maintenance due to their resistance to weather and corrosion, providing a lifespan of 40 to 60 years. Breast walls, constructed from masonry or concrete, require more frequent maintenance to prevent cracking and water infiltration but have a similarly long lifespan of 50 to 70 years when properly maintained. Both systems are designed for structural strength, yet curtain walls' modern materials enhance durability and reduce upkeep compared to traditional breast walls.
Cost Comparison: Curtain Wall vs. Breast Wall
Curtain walls generally have higher initial costs due to their complex structural framework and extensive use of glass and aluminum, but they offer long-term savings through improved energy efficiency and reduced maintenance. Breast walls, made from traditional masonry or concrete, have lower upfront expenses but may incur higher maintenance and limited thermal performance over time. Choosing between curtain wall and breast wall systems depends on budget priorities, with curtain walls favored for premium projects emphasizing aesthetics and energy savings, whereas breast walls suit cost-sensitive constructions.
Best Applications and Use Cases
Curtain walls are best applied in high-rise commercial buildings where maximizing natural light and providing weather resistance without supporting structural loads are critical. Breast walls are commonly used in residential or low-rise construction to support windows and provide a barrier between interior and exterior environments, particularly effective in retaining soil or as part of retaining wall systems. The choice depends on structural requirements, aesthetic preferences, and environmental factors such as wind load and thermal insulation needs.
Curtain wall Infographic
