Project managers are professionals who oversee the build on your behalf. They control all aspects of the project, which includes dealing with costs, safety, allocation of labour, planning and overseeing all contractors.
They will often have key contractors they have worked with before and can coordinate contractors' proposals.
Bear in mind they are expensive, typically charging around £100 - £200 an hour, adding around 10-15% to the full cost of a build. However, many self-builders see this as a worthwhile investment.
When it comes to your options for managing your self-build, it’s important to explore all of the above. Bear in mind that your budget, your time and the scale of the project will truly decide what route you take to ensure a smooth process of your self-build project.