In very broad terms, contractors are the organisations appointed by clients to carry out construction works. However, this apparently simple relationship is complicated by the fact that contractors tend not to have all the trades required to construct a building in their direct employment. This means that a contractor is likely to appoint a range of sub-contractors to build the works for which they have been contracted.
- General contractor, or main contractor, often appointed under s traditional contract to construct a development for which the design is complete.
- Construction manager. The construction manager manages trade contractors, but the trade contracts themselves are placed with the client. This generally requires an experienced client. A construction manager is generally appointed early in the design process so that their experience can be used to improve the buildability and packaging of proposals as they develop. A construction manager may also programme construction to begin before the design is completed. This requires careful planning of information release so that the construction process is not delayed by lack of production information.
- Management contractor. This is similar to the role of the construction manager but the trade contracts (or works contracts) are placed with the management contractor rather than with the client.
- Design and build contractor. Responsible for the completion of the design as well as construction.
- Prime contractors. The client enters into a long-term multi-project relationship with a contractor in which competition is introduced at the sub-contract level. Prime contracting is generally only appropriate for very large clients such as the Ministry of Defence which is continually commissioning new buildings and refurbishment work.
- Integrated supply team. This is favoured by the Government, and involves appointment of a full project team (including contractors, suppliers, designers and sometimes facilities managers) to design and construct the works.
- Design, build and manage contractors. The contractor is appointed not only to design and build the works, but also to manage them during operation, sometimes providing operational services over and above building maintenance, such as supplying prison staff or sterilisation of hospital instruments.
- Specialist contractors.
- Domestic sub-contractors.
- Nominated sub-contractors.
- Named sub-contractors.
- Trade contractors.
- Works contractors.
 Related articles on Designing Buildings Wiki
- CIS contractors and CIS sub-contractors.
- Commercial manager.
- Construction Industry Scheme.
- Construction manager.
- Construction contract.
- Contractor vs supplier.
- Management contractor.
- Principal contractor.
- Procurement route.
- Trade contractor.
- Works contractor.
 External references
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