The choice between rafters and trusses could depend on several factors: the age of the house, the pitch of the roof, the design of the ceilings, the proximity to a truss manufacturer, the preference of the builder. There are advantages and disadvantages of both approaches. Contractor Selection Workbook

The pitch of the roof is an important factor. The pitch of your roof could be determined by location and weather or design. High pitched hip roofs are not ordinarily built with trusses because the trusses would be too tall to move easily.

Location and weather are also factors. In northern locations where significant snowfall is likely, steeply pitched roofs are preferred because they prevent significant snow accumulation and damage to the roof or the structure of the home from the weight of the accumulated snow.

Home designs with very high ceilings or cathedral or other open beam high-pitch ceilings will also require a steeply pitched roof. Trusses cannot be altered on site; rafters can be. Trusses must be properly anchored or they can be damaged by high winds. Because they are factory built and joined, trusses tend to be very strong, as do rafters.

There is also essentially a cost trade-off for the two. While there will be a higher labor cost to cut and build with rafters, you will need to rent a boom to lift the trusses into position.

Many builders prefer trusses because they can be installed faster and because their dimensions are uniform. On the other hand, a rafter roof will be necessary for many complex or unusual roof designs.