Construction Specification

A construction specification makes a building plan concrete. Where a design, sketch or Program of Requirements mainly describes what should be created, the specification records how the work must be executed, which quality is expected and under which conditions contractors prepare their price.

That makes the specification an important contract document. It determines not only what will be built, but also what is included in the contract sum, which documents form part of the contract and how deviations, changes and additional work are assessed.

What is a construction specification?

A construction specification is the written elaboration of a construction assignment. It describes the works, materials, performance requirements, execution conditions and responsibilities that apply to the project. In professional construction, a specification is often prepared by an architect, consultant, building expert or cost specialist.

The aim is clarity before work starts. The client can compare quotations more effectively, while contractors know what they need to price. The more concrete the specification is, the less room there is for different interpretations during execution.

What is usually included in a specification?

The content differs per project, but a complete specification usually contains the following parts:

• Administrative provisions: agreements about planning, permits, insurance, responsibilities, handover and applicable conditions such as UAV 2012.
• Technical descriptions: the works, materials, products, quantities, quality requirements and execution methods.
• Drawings and appendices: references to specification drawings, detail drawings, reports, calculations and additional documents.
• Settlement rules: agreements about provisional sums, changes, omissions, additional work and how deviations are settled financially.

In Dutch residential and utility construction, the STABU system is often used. For civil engineering, road construction and hydraulic engineering, a RAW specification is often used.

Difference between a PoR, technical description and specification

The Program of Requirements mainly describes the wishes, goals and performance levels the client wants to achieve. A technical description is often more practical, but can still remain broad. The specification goes one step further: it makes the assignment contractual and executable.

A simple example:

• PoR: the house must be energy-efficient and comfortable.
• Technical description: underfloor heating will be installed on the ground floor.
• Specification: supply and install underfloor heating with defined zones, centre-to-centre distance, controls, insulation requirements, screed and handover criteria.

That level of detail matters when comparing quotations. Without clear specifications, two contractors can both submit a valid bid while pricing a very different quality level or scope.

Why is a specification important for quotations?

A quotation can only be compared properly when contractors price the same assumptions. The specification provides that shared basis. It prevents price differences from arising simply because components are missing, interpreted differently or deliberately included as provisional sums.

A good specification mainly helps with:

• comparing quotations on content instead of price alone;
• reducing ambiguity during execution;
• recording quality requirements and responsibilities;
• assessing whether a change falls inside or outside the original assignment.

Specification, drawings and Information Notice

A specification is never fully separate from other contract documents. Drawings show where elements are located and how they relate to each other. The specification describes the requirements, materials and conditions. In tenders, an Information Notice can later add clarifications or changes.

If documents contradict each other, the contractual order of precedence determines which document prevails. That order must be stated explicitly in the agreement or tender documents. Without a clear ranking, even a small difference between drawing and text can lead to discussion later.

Practical checks

Do not check a specification only for technical correctness, but also for completeness and consistency. Pay particular attention to open wording such as "to be determined", "or equivalent" without assessment criteria, missing quantities, unclear provisional sums and contradictions between text, drawings and appendices.

A specification does not need to be unnecessarily long. Above all, it should be precise enough to make the same assignment, the same quality level and the same risk allocation clear to all parties involved.