Construction superstructure work is a critical phase in architectural projects, involving the erection of the above-ground components that define the building’s shape, function, and durability. In Kenya, architects must carefully select walling systems that respond to local climate, material availability, and structural requirements, ensuring safety and aesthetics. Understanding the types of building walls is essential for designing structures that comply with national building codes and meet client expectations. This chapter explores the various walling types used in Kenya’s architectural practice, focusing on load-bearing walls, non-load-bearing walls, and curtain walls.

3.1 Building Walling Types

3.1.1 Load-Bearing Walls

Load-bearing walls are fundamental elements in many Kenyan buildings, particularly in residential and low-rise commercial structures. These walls carry and transfer structural loads from the roof and upper floors down to the foundation, thus playing a crucial role in the building’s stability.

Structural Role of Load-Bearing Walls

Load-bearing walls support vertical loads such as the weight of floors, roofs, and live loads including occupants and furniture. They must be designed to resist both compressive forces and lateral forces such as wind or seismic activity. In Nairobi’s medium-density housing, for example, load-bearing walls made of reinforced concrete blocks provide the necessary strength while optimizing construction costs.

Materials Used in Load-Bearing Walls

Common materials include concrete blocks, fired clay bricks, and stone masonry. Concrete blocks are favored in Kenya for their uniformity, strength, and ease of installation, allowing faster construction. Stone masonry is often used in rural settings where stone is abundant, offering durability but requiring skilled labor.

Design Considerations and Dimensions

Load-bearing walls require adequate thickness to support imposed loads; typical dimensions range from 150mm to 230mm depending on the height and load. Architects must consider wall length, height, and openings such as doors and windows, ensuring lintels or arches are incorporated to redistribute loads around these voids. In educational institutions like public schools, proper dimensioning prevents structural failures and enhances longevity.

Advantages and Limitations

Load-bearing walls reduce the need for complex frames, lowering overall construction costs. However, they limit architectural flexibility because wall positions dictate room layouts and future modifications can be difficult. This is why high-rise buildings in Nairobi use frame structures instead, reserving load-bearing walls for smaller projects.

3.1.2 Non Load-Bearing Walls

Non load-bearing walls are primarily used to partition internal spaces and do not carry structural loads except their own weight. They allow greater flexibility in interior design, which is particularly valuable in commercial and institutional buildings where space usage changes over time.

Functions of Non Load-Bearing Walls

These walls provide privacy, sound insulation, and fire separation between rooms without supporting floors or roofs. In hospitals, non load-bearing walls often separate wards and offices, enabling easy reconfiguration as patient needs evolve.

Materials Commonly Employed

Lightweight materials such as gypsum boards on metal studs, timber panels, and hollow concrete blocks are typical. Gypsum board walls are common in Nairobi office buildings due to their smooth finish and ease of installation, while timber panels are used in rural clinics for cost-effectiveness.

Installation and Structural Support

Non load-bearing walls require attachment to the main structural frame or load-bearing walls for stability. Proper fixing methods prevent movement and ensure durability. For instance, in a county government office, metal stud walls are anchored to reinforced concrete columns and beams for rigidity.

Benefits and Constraints

The main advantage is adaptability, allowing spaces to be changed without affecting the building’s structural integrity. However, these walls offer limited resistance to impact and require maintenance to prevent damage. Acoustic performance can also be a challenge, necessitating additional insulation in noisy environments like schools.

3.1.3 Curtain Walls

Curtain walls are non-structural external cladding systems that hang from the building frame, providing weather protection and aesthetic appeal. Their use in Kenya’s urban commercial towers and institutional buildings is increasing due to modern architectural trends.

Definition and Purpose of Curtain Walls

Curtain walls do not carry any load from the building other than their own weight and environmental forces such as wind. They form the building envelope, preventing water ingress and allowing natural light, which improves occupant comfort in office blocks and hotels.

Types of Curtain Wall Systems

Common types include stick systems, unitized systems, and structural glazing. Stick systems involve assembling mullions and transoms on site, suitable for large projects like Nairobi’s high-rise hotels. Unitized systems are pre-fabricated panels installed quickly, reducing construction time in university buildings. Structural glazing uses glass bonded to frames for sleek façades seen in commercial banks.

Materials and Components

Curtain walls typically combine aluminum frames, glass panels, and sealants. Aluminum’s corrosion resistance suits Kenya’s varying climates, while double-glazed glass improves thermal insulation. Sealants prevent water penetration and accommodate thermal expansion, critical for durability in coastal cities like Mombasa.

Performance and Maintenance

Curtain walls enhance energy efficiency by controlling solar gain and reducing heat loss. Regular maintenance includes cleaning glass surfaces and inspecting seals to prevent leaks. In Nairobi’s commercial buildings, maintenance contracts ensure façade integrity and preserve the building’s visual appeal.

Chapter Summary

This chapter explored the principles of construction superstructure work, beginning with various building walling types including load-bearing walls, non load bearing walls, and curtain walls, each serving distinct structural and aesthetic functions. It then examined the installation of building openings such as doors, windows, and arches, highlighting their importance in access, ventilation, and architectural design. The chapter provided a detailed overview of building concreting works, covering key processes like batching by weight and volume, manual and mechanical mixing, placing, compacting, and curing to ensure durable concrete structures. Different concreting areas were discussed, focusing on foundations, beams, slabs, columns, and retaining walls, each requiring specific concreting techniques. Roof construction elements were also covered extensively, addressing timber and steel sections, roofing coverings and materials, as well as framing methods. Finally, the chapter emphasized the role of insulation, ventilation, and flashing in protecting the roof and enhancing building performance. Together, these topics provide a comprehensive foundation for understanding and applying superstructure construction principles effectively.