Summary of Quantity Surveying: Measurement and Cost Estimation

## Introduction Construction projects rely on a wide range of specialized trades and labour categories to deliver buildings that are functional, durable and safe. This material summarizes the principal trades listed in the Standard System of Measurements and explains what each trade covers, typical materials and workmanship considerations, and real-world applications. > Definition: A trade in construction is a specialized branch of work performed by skilled labourers or subcontractors covering materials, methods and quality standards for a specific part of a building. ## Overview of Major Trades The following sections break the listed trades into digestible groups. Each trade note includes what is covered, typical specifications and practical examples. ### Concrete, Formwork and Reinforcement - Covers: different classes of concrete, formwork types (timber, plywood, steel or reusable systems) and required steel reinforcement (bars, mesh). - Key considerations: concrete grade, curing, compaction, formwork tolerances, cover to reinforcement and fixing methods. > Definition: **Formwork** is a temporary structure used to contain freshly placed concrete until it gains sufficient strength, and **reinforcement** is steel used to resist tensile forces in concrete elements. Practical example: For a reinforced concrete beam you must specify concrete grade (e.g. C30), bar sizes and spacing, formwork support spacing and minimum cover to reinforcement. ### Precast Concrete - Covers: factory-made concrete elements such as beams, slabs, stair flights, panels and facade units. - Key considerations: dimensional tolerances, lifting and handling accessories, jointing, connections and on-site grouting or bedding. Practical example: Precast wall panels are delivered with lifting inserts; specification includes panel dimensions, reinforcement, finishes and approved lifting plan. ### Masonry - Covers: masonry materials, unit types (clay brick, concrete block, lightweight block), bonding patterns and mortar classification. - Key considerations: unit strength, mortar mix (e.g. cement:lime:sand ratios), bed joint thickness, bond patterns and movement/expansion joints. > Definition: **Masonry unit** is an individual block or brick; **bond** is the pattern in which units are arranged to ensure structural interlock. Practical example: External facing walls may require stretcher bond with Type N mortar and bed joint of 10 mm. ### Waterproofing - Covers: membranes, liquid-applied systems, bituminous felts and detailing at junctions, upstands and penetrations. - Key considerations: substrate preparation, compatibility with finishes, exposure class, and detailing for drainage and interfaces. Practical example: A flat roof deck may receive a multi-layer bituminous system with tapered insulation for positive drainage and flashings at upstands. ### Roof Coverings - Covers: tiles, slates, metal sheeting, built-up roofing and installation accessories (battens, flashings, fixings). - Key considerations: substrate, wind loading, fixing patterns, underlay, eaves and ridge details. Practical example: Clay tiles fixed to battens over breathable underlay with metal flashings at valley and ridge. ### Timberwork - Covers: species selection, timber grade, preservative treatment, structural carpentry (frames, rafters, joists) and joinery items. - Key considerations: moisture content, seasoning, structural grade (e.g. C16, C24 where applicable), and required preservative treatment for durability. > Definition: **Preservative treatment** is the process applied to timber to protect against decay and insect attack. Practical example: External joists in contact with ground must be treated to a specified retention level and use certified species or engineered timber. ### Ceilings, Partitions and Access Flooring - Covers: suspended ceilings, removable access floors, partition types (single/double stud; glass; metal studs) and acoustic/thermal insulation. - Key con