Types of construction specifications

Construction specifications can simply be defined as technical documents that describe in details the work that needs to be completed in a construction project.

The documents, which are usually prepared by architects and designers – with advice from project engineers, provide details such as materials to be used, the scope of work, installation procedure, and the quality of work to be carried out by contractors and subcontractors.

Unlike blueprints that illustrate what a building should look like visually, construction specifications go beyond appearances to include intricate specifics that cannot be expressed in drawings and photographs.

As a matter of principle, some companies will never bid for a project unless they are issued with construction specifications since without these documents it is almost impossible to calculate pricing for the work, building materials, and labour necessary to complete the project.

The importance of specifications in construction cannot be overemphasised. Project teams are required to follow the specs to the letter to ensure proper execution of a project.

So important are construction specifications that once specs are discussed between the project owner and the contractor the document becomes a part of the legal booklets of the project.  

Types of construction specifications

What are the different types of specifications? There are three types of construction specifications, including performance, prescriptive, and proprietary specs – which go beyond what drawings and videos can describe in detail.

1. Prescriptive specifications

Prescriptive specifications offer specifics of the types of materials to be used on a specific project, while describing what installations will be required to complete the project. In addition, the specs also define how installations will be examined to make sure they are up to the project’s quality and standards.

This means the prescriptive specs give a clearer image of what a building would look like compared to the other specs. In fact, architects or engineers often take over the task of project design in prescriptive specifications.

In construction specification 101, prescriptive specifications are broken up into three separate categories that include general, products, and execution.

The general category comprises details such as quality standards, product handling, design requirements, and quality control. On the other hand, the products segment highlights the diverse products necessary for each assignment as well as the individual performance levels of each product.

The execution part covers material preparations and how to undertake their installation. It also involves testing the quality of the materials and examining if they were installed correctly.

2. Performance specifications

Once prescriptive specifications are finalised, performance specs are prepared to describe the operational requirements of the project. Essentially, the specs tell the contractor what is required for the final product and how the installed product will function.

It is important to note that this phase does not offer details on how to finish a job. Instead, it gives contractors details on how the final product has to work in this segment.

For example, the team is asked to make a water pump that pushes 250 gallons per minute without offering directions on how to make the pumping system meet that requirement.

In performance specifications, the architect or engineer simply defines a project outcome and leaves the contractor to use his skills to meet the operational requirements. At this point, it is the contractor – not the architect or engineer – who makes the choices on materials and approach.

3. Proprietary specifications

These are the least common types of construction specifications. They are used by contractors in situations where they only need to use a single type of product for an installation.

For example, when a project owner wants to be consistent with materials or just fancies a certain type of material, he or she uses proprietary specifications. On their part, contractors use the specs when their segment of the project depends on the performance of a specific product.

Architects and engineers rarely use proprietary specs because they can result in endorsement of a producer. This can break competition during the bidding phase – which can lead to cost escalation.

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