Preparing a proper building specification

A specification document is a key element in any construction project

A construction specification is a well-structured, detailed description of the quality, standards, workmanship, materials, and completion of work to be done which evolves across a project. A good specification helps maintain the quality of detailing and workmanship and saves time, money and potential issues later on. It can also decrease the time it takes to process consent applications, improve the accuracy of quotes, reduce the number of changes or rework on the building site and prevent disputes between the builder, designer and owner.

The specification information describes in words things that cannot be visualized or explained in drawings and the model. The content can include site requirements, contract information, client requests, performance criteria to be achieved, the quality of products needed, references to various standards applicable to the materials and systems selected, how work is to be completed and tested, and maintenance of the building in-use.

A specification defines how a building is to be constructed, altered, demolished or removed. For a new project, it must define the intended use of the building, detail all the systems and materials used and provide procedures for installation, inspection and maintenance during and after construction.

To estimate the cost of a project without a specification is impossible and to enter into a contract without one is very short sighted. Too many building contracts are entered into with vague information, resulting in a myriad of problems; the most common being significant cost overruns. The specification should form an integral part of the building contract. It is also important to note that there is no such thing as a standard specification as no two structures are alike or use the same materials.

Specifications are often prepared by architects, engineers, and designers, referred to as specifiers, and the various parties each use the specification in a slightly different way. The designer uses it to accurately describe the components and expected standard of the build, the builder uses it to carry out the construction and the owner uses it as part of their agreement with the builder. As the specification is used as the guide for all parties to the construction, it is essential that the specifier has the required knowledge of regulatory requirements and construction techniques to create a good specification.

Different types of specification can be used at different stages of a project’s development. At an early stage, requests from the brief and high-level design ideas can be captured as an Outline description, then requirements of the building, systems and products can be specified in performance terms in a Descriptive or Performance specification, such as the acoustic, thermal, or structural requirements, and the specification further developed into more Prescriptive clauses selecting the standards, grades, and materials of component products. Proprietary specification includes product information like range names, reference codes, and key properties selected from manufacturer choices. The specification is often developed in tandem with Preliminaries, managing the contractual and project-wide requirements, and will continue to evolve as changes are requested, eventually forming handover data, for example as a record specification.

There are seven key principles to writing a robust specification, and are called the 7 Cs of specification:

  • CLEAR: Use clear, plain language and short phrases to list requirements. Avoid ambiguity to improve understanding for all users
  • CONCISE: Don’t include information that isn’t required or relevant – make the specification project-specific.
  • CORRECT: Clarify requirements, refer to outcomes, and reference relevant standards wherever possible.
  • COMPLETE: Check the depth of information is appropriate.
  • COMPREHENSIVE: Ensure all aspects of the project are covered and use cross-references to avoid repetition or conflicts.
  • CONSISTENT: Use standard structure, terminology, and style. Keep outputs neat when published, so they are easy to navigate and understand for all receivers.
  • CO-ORDINATED: Ensure that drawing references in the specification are kept to up-to-date to match model annotations and other contract documentation.

Like any good technical document, a specification should present information in an easy to follow and logical sequence. Its aim is to ensure that each stage of the project proceeds smoothly without time delays, inaccurate costings or legal issues and enables parties involved in the construction to communicate effectively.

Order the right strength class of cement

One key oversight that can be made in the planning phase of a construction project is ordering the wrong strength class of cement. It is critical to understand that not all cement is the same and with various types of cement to choose from, this can often be a challenge.

With different strength classes and different strength gains, there is a lot to take into consideration.

For instance, if your project is a building structure like a home, general purpose cement that reaches strength at a normal age will be suitable. However, if you are working on a larger civil engineering project that requires day one strength, high performance cement may be required.

By taking the time to find the right cement for your project, you will ensure the desired result and long-term durability of the structures you build. 

Keep your calculations in check

Another miscalculation that can affect the preparation phase of a construction project can be made when calculating the amount of concrete required for a project. Concrete is made up of cement, water, and aggregates like sand and gravel. By calculating the required amount of concrete necessary for the project, this will in turn ensure that you have the right amount of cement, water and aggregates for your project. 

This can be achieved by applying a concrete calculator formula. The first step is to identify how thick the concrete needs to be and then measure the length and width of the area that needs to be covered. Once you have all the above required information, there are a variety of concrete calculators out there to help you figure out the exact amount necessary for your project.

Get water-to-cement ratios (W/C) right

Water is one of the ingredients used in the mixing of concrete and the water-to-cement ratio (W/C) is critical to the formulation of your concrete and needs to be meticulously worked out. Information on W/C ratios can be obtained from cement manufacturers for all types of their cement.

Using the wrong water-cement ratio (W/C) is one of the mistakes often made in the mixing of concrete. If concrete is mixed with too much water, it can lead to segregation of materials that causes excessive bleeding (water migrating to the top). This often leads to voids in the concrete matrix that negatively affects strength and durability.

Too much water in the mix will further impact the hydration process and ultimately, the cement’s ability to achieve strength, negatively. “Wet mixes” may experience a greater amount of shrinkage during the curing process which can result in cracks and other issues.

On the other hand, if you do not add enough water to your concrete mixture, this too builds in its own issues. Cement requires sufficient water for it to be workable (placed and compacted) and you therefore need to ensure that the of water-cement ratio (W/C) is just right. Too little water will result in dry, unworkable concrete mixes which again can impact the hydration process negatively, causing the cement not to achieve the required strength.

Critical consistency in concrete mixing

Once you have worked out the type of cement you would need to use, calculated the amount of concrete that is required, and ensured you are using the right amount of water in your mixture, it is time to start mixing.

Remember that mixing concrete may require more than one load. This means that each batch of concrete needs to be mixed the same way. This is another oversight that is often made in the process of mixing concrete and is important because it may affect the finished product.

Don’t forget that there are tried and tested solutions to avoid these few common pitfalls and fix any mistake when you are mixing your Sephaku Cement into your concrete.

Overall, be sure to apply the recommended concrete mixing guidelines provided on the cement bag and ensure an even amount of cement, water and aggregates is used in each batch of concrete mix, as this will deliver a result with which you are sure to be satisfied. One that will last a lifetime.

function wpf_dev_num_limit() { } add_action( 'wpforms_wp_footer_end', 'wpf_dev_num_limit', 30 );