Erecting and dismantling scaffolding is a core responsibility for quantity surveyors involved in building temporary works. Understanding the different types of scaffolds is essential for accurate cost estimation, resource planning, and risk assessment in construction projects. Kenyan quantity surveyors must be conversant with scaffold types suited to various site conditions and project requirements to ensure safety, efficiency, and compliance with local regulations such as the Occupational Safety and Health Act. This chapter explores the main types of scaffolds used in Kenya’s construction industry, with emphasis on practical considerations relevant to quantity survey professionals.

3.1 Types of scaffolds

Scaffolds provide temporary elevated platforms to support workers, materials, and equipment during construction activities. Selecting the appropriate scaffold type affects project timelines, budget, and safety standards. Kenyan construction sites range from urban high-rise developments to rural infrastructure projects, demanding versatile scaffold solutions. Quantity surveyors must understand the characteristics, advantages, and limitations of each scaffold type to prepare precise bills of quantities and advise on cost-effective temporary works.

3.1.1 Supported Scaffolds

Supported scaffolds are the most common scaffolding type on Kenyan construction sites, characterized by platforms supported by rigid frames or poles from the ground. Their widespread use in schools, hospitals, and commercial buildings reflects their relative simplicity and adaptability to various heights and working conditions.

Characteristics of Supported Scaffolds

• Ground-based support: Supported scaffolds rest on the ground or a solid base, ensuring stability and load-bearing capacity.
• Modular construction: Components such as standards, ledgers, and transoms are assembled to form a rigid structure adaptable to different heights and widths.
• Material versatility: They can be constructed using steel, timber, or aluminium depending on site availability and budget constraints.
• Load capacity: Designed to carry workers, tools, and materials safely, with load ratings specified by manufacturers and local standards.
• Access provisions: Equipped with ladders or stairways integrated into the scaffold design for safe worker movement.

Advantages and Applications

• Easy to erect and dismantle, reducing labour costs and time.
• Suitable for a wide range of construction activities including bricklaying, plastering, and painting.
• Commonly used in urban projects such as county government office renovations and university building works.
• Cost-efficient due to reusable components and minimal foundation requirements.
• Compatible with safety features like guardrails and toe boards to prevent falls and material drop hazards.

3.1.2 Suspended Scaffolds

Suspended scaffolds hang from structures via ropes or chains, providing access to elevated work areas without ground support. In Kenya, they are essential for projects where ground space is limited or uneven, such as façade repairs on hospitals or high-rise office blocks.

Functional Features of Suspended Scaffolds

• Hanging platform: Platforms are suspended by wire ropes or chains from overhead supports, allowing vertical movement.
• Adjustability: Height can be adjusted by raising or lowering the scaffold to access different levels.
• Compact footprint: Since no ground support is needed, they are ideal for congested urban sites or uneven terrain.
• Safety mechanisms: Equipped with safety harness anchors, emergency brakes, and controlled hoisting systems.
• Material handling: Capable of supporting workers and moderate material loads within specified limits.

Typical Uses in Kenya

• Window cleaning and external painting of Nairobi’s high-rise buildings.
• Maintenance work on county government office façades where ground scaffolding would obstruct access or traffic.
• Repairing structural elements of university lecture halls with limited ground access.
• Installation of signage and external lighting on commercial hotels.
• Inspection and repair of bridges and water tanks in urban and peri-urban areas.

3.1.3 Mobile Scaffolds

Mobile scaffolds are supported scaffolds mounted on wheels or castors, enabling easy relocation around the site. Their mobility makes them highly suitable for dynamic work environments such as retail shops or hospitals undergoing phased renovations.

Features That Define Mobile Scaffolds

• Wheeled base: Equipped with lockable castors to allow movement and secure positioning.
• Adjustable height: Platforms can often be raised or lowered using manual or hydraulic mechanisms.
• Lightweight construction: Typically made of aluminium or lightweight steel for ease of handling.
• Compact size: Designed for tight spaces and indoor use where fixed scaffolds are impractical.
• Safety locks: Wheels have brakes to prevent unintended movement during use.

Practical Applications in Kenyan Context

• Repainting and electrical maintenance in county hospitals where patient access must remain clear.
• Installation of ceiling fixtures and HVAC systems in university lecture halls.
• Maintenance work in retail stores during off-hours to minimize disruption.
• Temporary access for inspection and repair in cooperative office buildings.
• Phased construction activities in hotels where rapid relocation of scaffolds improves workflow.

3.1.4 Cantilever Scaffolds

Cantilever scaffolds are supported at one end, typically anchored to the building or structure, allowing the platform to extend beyond the base without ground support underneath. This arrangement is useful where ground conditions prevent erecting standard scaffolds.

Defining Characteristics of Cantilever Scaffolds

• Anchored support: The scaffold is anchored to the structure using needles or brackets that transfer loads safely.
• Extended reach: Platforms can project over obstacles such as roads, footpaths, or uneven ground.
• Load considerations: Requires careful calculation of load distribution and anchorage strength.
• Complex erection: Installation demands skilled labour and engineering input to ensure stability.
• Safety features: Guardrails and toe boards are mandatory to protect workers from falls.

Usage Scenarios in Kenya

• Construction over narrow urban streets where ground scaffolding would obstruct traffic.
• Repair works on school buildings adjacent to busy pedestrian walkways.
• Renovation of county government offices where landscaping or utilities prevent ground support.
• Installation of external cladding on hotels with limited site space.
• Maintenance of water tanks in farms where terrain is uneven and inaccessible.

Chapter Summary

This chapter covered the various types of scaffolds commonly used in construction, emphasizing their specific structures and applications to ensure suitability for different tasks. It detailed the importance of scaffold drawings as a guide for correct assembly, highlighting how accurate plans contribute to safety and efficiency on site. The processes involved in assembling and dismantling assignment scaffolds were explained step by step, focusing on methods that maintain structural integrity throughout. The chapter also underscored the critical role of personal protective equipment in safeguarding workers from potential hazards during scaffold operations. Site safety requirements were discussed comprehensively, outlining necessary precautions and protocols to prevent accidents. Finally, the chapter addressed site clearance procedures, stressing the importance of maintaining a tidy and hazard-free environment around scaffolding to support safe working conditions.