A specification (or building specification) is the written document that sets out all technical requirements, materials, workmanship standards and conditions for a construction project. The specification, together with the construction drawings, forms the basis of a tender and the building contract between client and contractor.
What does a specification contain?
A complete building specification typically includes:
- General conditions — administrative terms, programme, penalties for delay
- Technical descriptions — per building element (foundations, shell, roof, services) a description of materials and methods of construction
- Quality requirements — which standards and certification marks apply (e.g. BS, CE, BBA)
- Quantities — numbers, areas and volumes per element
- Specification clauses — references to standard contract conditions
Specification vs. construction drawing vs. building permit
| Document | Content | Purpose |
|---|---|---|
| **Specification** | Technical requirements, materials, conditions | Basis for pricing and execution |
| **Construction drawing** | Floor plans, sections, details | Visual representation of the design |
| **Building permit** | Approval from the local authority | Permission to build |
Why is a specification important?
- Price comparison — contractors price on the basis of the same specification, making quotations comparable
- Quality assurance — the specification records which materials and methods are to be used
- Legal basis — in the event of a dispute, the specification is the reference document
- Preventing extras — a detailed specification limits surprises during construction
Specification for the DIYer
For smaller renovations you do not normally prepare a full specification, but it is wise to draw up a work description including:
- What work you will carry out (and in what order)
- What materials you need (type, quantity, brand)
- Which standards apply (e.g. insulation value, fire safety)
- A cost estimate per element
Related terms
- Construction drawing
- Building permit
- Zoning plan
- Building regulations
- Planning permission
- Detail drawing