Samples and mock-ups for construction

Samples and mock-ups have become more common requirements on construction projects as the number and complexity of goods and materials that are available and that are required for a single project has increased.

Samples might include simple items such as paint, tiles, bricks, or carpets. Mock-ups are scaled-down or full-size assemblies, such as sections of cladding, window assemblies or masonry.

There are a number of reasons that samples and mock-ups may be required:

• They may be required as part of the tender process when alternative suppliers or products are being considered before an order is placed.
• They may be required after selection to demonstrate compliance with the specification, to allow review of appearance or for testing to be carried out.
• Some suppliers may prepare them themselves to verify their ability to produce a product to the required specification.

The benefits of requiring samples or mock-ups include:

• Lessons can be learned from failures discovered through the tests that are performed.
• Potential issues and causes of failures can be taken into consideration and mitigated against.
• The process of testing and approval can improve the durability and longevity of the finished building.
• They can help test the way installed materials interact.
• They can help improved energy efficiency.
• They provide assurance that the specified materials will function as required under a variety of conditions.
• They can help understand the boundaries between trades.
• They can help improve installation techniques prior to actual work beginning.
• They can be useful obtaining approval from stakeholders who may find it difficult to understand drawings and specifications.

Mock-ups can be built and tested either on site, as part of the building itself, at the manufacturer’s premises, or in a third-party testing facility such as a laboratory.

The benefits of the manufacturer’s premises or a testing facility are that the controlled indoor environment can allow for quicker testing, and alterations to the product and the testing procedure can be made relatively easily. Laboratory conditions are also more likely to produce more reliable test results. However, this may involve the project team and the client travelling to the facility, and there may be time limitations, travel considerations, and additional costs involved.

The benefits of site-built mock-ups are that the installation can take place under the actual conditions that the actual structure will be exposed to, there are no additional travel or hire fees, and there are likely to be fewer time constraints. Potential drawbacks include difficulties in the construction and testing schedule because of inclement weather, site conditions, site availability, and so on.

If mock-ups are required, the project documents and specifications should include the precise requirements and test procedures. Test procedures should cover the specific tests, how they will be carried out, the conditions under which the test should be carried out, the qualifications for pass or failure and any requirement for witnesses to attend, such as designers or the client. This allows for the cost of the mock-up to be included as part of the original bid.

Once the supply contract has been let, comments on samples and mock-ups can only be made in relation to what is allowed by the contract. Comments that amount to a change in requirements would have to be consented to by the supplier and may result in an adjustment to the contract sum and a claim for extension of time.

[edit] Related articles on Designing Buildings

• Buildability in construction.
• Computer-generated imagery (CGI).
• Construction progress meeting.
• Construction site inspection.
• Contingency plan.
• Design review.
• Layer.
• Model-based design.
• Modular building.
• Offsite manufacturing.
• Pre-construction information.
• Prefabrication.
• Quality control.
• Tolerances.