1. Scope
Class Z covers basic building works required as part of civil engineering projects but which are not complex enough to require full building measurement rules (as per SMM or NRM).
These are usually ancillary or incidental works, provided to support the main civil engineering works.
2. Types of Works Included
Class Z may include:
- Small buildings and shelters
- Site offices, security cabins, pump houses, control rooms, substations, switchgear rooms.
- Guard huts, toilet blocks, small workshops.
- Boundary and fencing works
- Compound walls, fencing, gates.
- Miscellaneous masonry and concrete works
- Minor blockwork or brickwork walls.
- Foundations, plinths, flooring.
- Roofing and cladding
- Simple steel or timber roof trusses.
- Corrugated sheet roofing, sheeting, cladding.
- Finishes and joinery
- Plastering, painting, whitewashing.
- Simple timber/metal doors and windows.
- Plumbing and drainage
- Simple water supply, waste disposal, rainwater pipes.
- Electrical installations (basic)
- Lighting, small power supply for the incidental building.
3. Method of Measurement
- By number (No.) → For small buildings measured as complete units.
- By area (m²) → For walls, roofing, flooring, painting.
- By length (m) → For fencing, pipes, gutters, downpipes.
- By weight (t or kg) → For structural steelwork.
- By volume (m³) → For foundations, mass concrete.
4. Item Coverage
Unless otherwise stated, items include:
- Supply of all materials, plant, and labour.
- Setting out, excavation, and disposal of surplus.
- Construction, erection, and finishing as required.
- Incidental fittings, fixings, fasteners.
- Testing and commissioning of plumbing/electrical installations.
5. Notes for BOQ Preparation
- Class Z is used only when simple building works are incidental to a civil engineering project.
- For major or complex buildings, measurement must be done using building-specific rules (not CESMM).
- Clearly describe the purpose and size of the incidental building.
- If the building includes special finishes, equipment, or high-quality works, they should be measured separately or under appropriate classes.
6. Example BOQ Items
- Z.1.1: Construction of brick-built guard hut 3 m × 3 m with RCC roof slab, finished with cement plaster and painting, measured per No.
- Z.1.2: Supply and erection of corrugated sheet roofing over pump house (50 m²), including steel purlins and fixings, measured per m².
- Z.1.3: Chain-link fencing 2 m high with angle iron posts at 3 m spacing, measured per m.
- Z.1.4: Mild steel gate 3 m wide, fabricated and installed, measured per No.
- Z.1.5: Painting to walls of incidental building with two coats plastic emulsion over primer, measured per m².
- Z.1.6: PVC water supply pipeline 25 mm dia inside control room, measured per m.
- Z.1.7: Electrical wiring and light fittings in site office, measured per Lump Sum.
✅ In summary:
Class Z provides for small, simple building works that are incidental to civil engineering projects — like site offices, pump houses, fencing, guard huts, small masonry works, roofing, finishes, plumbing, and electrics. Anything beyond “simple” must be measured under building rules.
