There isn’t a difference between truss and pitched roofs, because all truss roofs are pitched roofs. When a pitched roof system is unable to internally support itself, trusses are added in order to make the roof more secure. They are typically found in large pitched roofing systems, and only very rarely in smaller ones; usually to help support heavier roofing materials.

Trusses are made from wood, which is ideal for the task due to its strength and flexibility. Steel girders are used as well in metal and glass roofing constructions, but aren’t used in brick and mortar buildings.

There are a number of problems with trusses which make choosing a pitched roof with them over a supported flat roof an issue. Trusses need to remain secure, as any movement in the roof, caused by further building work, could damage the integrity of the building.