A conditional contract is an agreement that is used when no service could be provided at the time the contract was signed. It sets a date when benefits will be provided if certain conditions are met. Time and equipment contracts are generally preferred when the scope of the project is unclear or has not been defined. The owner and contractor must set an agreed hourly or daily rate, including the additional costs that could be incurred by the construction process. Costs must be classified as direct, indirect, dependent and in common. Sometimes the owner may want to set a ceiling or project time to the contractor that needs to be filled in order to minimize the owner`s risk. A construction contract is a document that sets a date and determines which parties will participate in the construction process. As a general rule, the contract between the project owner and the contractor or supplier providing the requested services is concluded and contains several sections of clauses defining the scope, conditions and terms of such an agreement. In the context of a reassessment contract (or a revaluation), the price to be paid for the entire work must be determined by measuring in detail the different parts of the work and assessing the work done using a price plan included in the contract.  The 4th edition of the Fidic Red Book  (the predecessor of the 1999 Red Book) is used in some parts of the world as a reassessment contract for civil engineering work.  Duke and Carmen stated: „Cost-plus with GMP offers a cap on total construction costs and costs for which an owner is responsible. If the party that provides the work according to this method of price goes through GMP, it is responsible for such overruns… Cost-pluses with GMP and a cost-sharing agreement can encourage both parties to enter into a construction contract in the most efficient way possible.  The concept of contractor comes from the legal agreement.
There will be a legal agreement between the owner and the owner. A contractor may be a contractor, but a contractor may or may not be a contractor. For the execution of civil engineering work, the following are the different types of contracts: in the contract, the work is carried out according to the plan and specifications by the contractor, for a fixed amount determined, in accordance with the agreement. The owner provides the necessary information and the contractor calculates a certain amount. This contract is appropriate if the number of items is limited or if it is possible to develop exact amounts of work to be done. Detailed specifications of all work points, detailed plans and drawings, deposit, penalty, progress and other contractual conditions are included in the Convention. Although it is a lump sum and a planned contract, the contractor is paid at regular intervals of 2 to 3 months after demsol work on the basis of a certificate issued by the competent engineer. A planned price is included in the agreement for the payment of additional items. This type of agreement defines very well the purpose and scope of the agreement. By this alternative, the provisions and contractual terms of each party are clearly understood.
These types of contracts are appropriate when a specific scope and timetable have been verified and agreed upon.