Objectives

The primary objective of this tender is to restore the structural integrity and weatherproofing capacity of an existing roof slab by completely removing a failed waterproofing system. The project aims to eliminate water ingress, optimise surface drainage through corrected gradients and outlet configurations, and improve thermal performance using a high-reflectivity finish.

Scope of Work

The contract encompasses all labour, materials, plant, and waste management services required for approximately 750 square metres of roof slab. The scope includes:

• Complete stripping and environmentally compliant disposal of the existing failed waterproofing layers
• Substrate rectification to establish correct roof falls and modify or reposition drainage outlets
• Installation of a new 4 mm torch-on waterproofing membrane across the entire designated area
• Application of two full coats of silver (aluminium) reflective paint over the cured membrane

Technical Requirements

Tenderers must satisfy the following technical criteria:

• Minimum Contractor Classification: CIDB grading of 1SN or higher
• Use of Derbigum 4 mm torch-on membrane systems that comply with applicable South African National Standards (SANS) and manufacturer specifications
• Comprehensive surface preparation, including cleaning, priming, and detail work at edges, penetrations, and outlets
• Precise geometric profiling of the slab to achieve specified falls directing water toward outlets
• Uniform application of industrial-grade aluminium reflective coating with verified dry film thickness
• Strict adherence to occupational health, safety, and environmental regulations governing hot-work operations and hazardous material disposal

Skills Requirements

The tender notice does not explicitly list personnel qualifications; however, the CIDB 1SN classification and the technical nature of the works imply the following competency requirements:

• Certified torch-on membrane applicators trained in controlled flame application and fire-safety protocols
• Experienced roofing supervisors proficient in drainage profiling, outlet detailing, and substrate remediation
• Qualified coaters/painters experienced in metallic reflective industrial finishes
• Site management capability to integrate demolition, civil rectification, membrane installation, and finishing into a coordinated workflow

Key Terminology & Clarifications

CIDB 1SN Grading: A South African Construction Industry Development Board classification for small-scale specialised building contractors. It authorises execution of niche trade projects typically valued up to R10 million and requires documented experience in specialised works such as roofing and waterproofing.

Derbigum 4 mm Torch-On Membrane: A polymer-modified bitumen waterproofing sheet applied using regulated open flames. This installation method requires precise heat control, certified operators, and rigorous fire-prevention measures to ensure full adhesion, seam integrity, and site safety.

Silver (Aluminium) Reflective Paint: A metallic-pigmented protective topcoat engineered to reflect solar ultraviolet and infrared radiation. It significantly reduces roof surface temperatures, minimises thermal cycling stress on the underlying membrane, and enhances overall building energy efficiency.