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Estimating process

Scope of works breakdown.

Breaking the project into structured work sections is the foundation of every good estimate. A clear scope breakdown ensures nothing is missed and makes the estimate easier to review and price.

Who this guide is for

Estimators organising their work, quantity surveyors structuring cost plans, and project managers defining the works package breakdown for procurement.

Typical scope structure

Following NRM2 or SMM7, a typical breakdown includes: substructure, superstructure (frame, walls, floors, roof), finishes, fittings and furnishings, services, prefabricated buildings, external works, and main contractor preliminaries. Each section is further divided into measurable items.

Miniature example

Scope breakdown for a single-storey extension:
1. Substructure — foundations, ground floor slab, dpc
2. Superstructure — external walls, roof structure, roof covering
3. Finishes — plastering, floor finishes, decoration
4. Fittings — kitchen units, sanitaryware
5. Services — plumbing, electrics, heating
6. External works — rainwater goods, paving, planting

Common mistakes

• Creating work sections that are too broad, hiding the detail needed for accurate pricing
• Missing sections entirely — external works and services are common omissions
• Not matching the scope structure to how the project will be procured or managed