What are the three main contract types used in construction?

What are three main contract types used in construction include fixed price, cost plus, and time and materials, plus variations. Three main contract types used in construction, which is industry building residential and commercial buildings, with contracts governing relationship between client and contractor, include fixed price contract, also called lump sum contract, where contractor agrees to complete project for fixed price agreed upfront, with price including all materials, labor, and profit, with risk on contractor if costs overrun, common for residential building in NZ with standard NZS 3910 and NZS 3902 contracts, and cost plus contract, also called cost reimbursement contract, where client pays actual costs of materials and labor plus agreed fee or percentage for contractor profit, typically 15 to 25 percent, with risk on client for cost overruns, used when scope uncertain, and time and materials contract, where client pays for time spent at agreed hourly rates plus materials cost, used for small jobs and maintenance. Another classification includes traditional contract with separate design and construction, design and build contract where contractor does both design and build, and construction management contract. So three main contract types in construction are fixed price lump sum with fixed price risk on contractor, cost plus with actual costs plus fee risk on client, and time and materials with hourly rates plus materials, with fixed price most common for residential building in NZ under NZS contracts.