Most project teams in the construction industry are thrown together. In some cases, of course, this is not the case: they are teams which have worked together successfully before, but this is far from being the rule.
All too often, they are assembled ad hoc, and this may mean that there are in-built factors of incompatibility which from the start give rise to tensions and a failing project culture.
The project manager needs to be appointed early and thus have a chance of influencing the composition of the team. This is an area where developed project management skills can add significant value to a project. The PM is not merely a technically-adept administrator; s/he has skills which can add to the synergy of a team: its horsepower.