The involvement of boilermakers in the shipbuilding and engineering industries came about because of the changeover from wood to iron as a construction material.

In the UK, this effective monopoly over an important skill of the industrial revolution led to boilermakers being labeled "the labour aristocracy" by historians.

Stress fractures, leaks, and corrosion demand continual repair or replacement resulting from operation at very high steam pressures.

Other boilermakers might work seasonally or on an individual project such as re-fitting a boiler in a seagoing vessel or remodeling a steam plant.

[1] Boilermakers usually go through a formal apprenticeship which includes about four years of paid on-the-job training combined with classroom instruction.