What is a Building Specification?
A building specification is a comprehensive technical document that precisely describes how a structure must be built: which materials are used, which quality requirements apply, and how the work is to be carried out. Together with the construction drawings, the specification forms the complete building documentation and serves as the basis for requesting quotes and concluding construction contracts.
Contents of a specification
A complete building specification contains:
- Administrative provisions — who is the client, who is the contractor, liability
- Technical description — materials and execution described per building element
- Quality requirements — standards, certifications, tolerances
- Execution guidelines — sequence, working methods, safety measures
- Schedule of materials — quantity list per item
Specification vs. construction drawing
| Document | What it shows |
|---|---|
| Construction drawing | How it looks (dimensions, shapes) |
| Building specification | How it is made (materials, quality) |
| Together | Complete building documentation |
Standard specification systems
Commonly used systems include:
- NBS (National Building Specification) — for buildings in the UK
- MasterFormat — widely used in North America
- Uniclass — classification system for construction elements
For DIY builders
As a private individual, you don’t need to write a formal specification for small jobs. But for larger projects (extensions, garages, outbuildings) a simple description is useful:
- Which materials will you use?
- What type of foundation?
- Which timber? Which insulation?
- What are the dimensions?
This helps when comparing contractor quotes and prevents misunderstandings.
Related terms
- Construction drawing
- Planning permission
- Detail drawing
- Building permit
- Pad foundation
- Reinforcement
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