They can be built indoors, ahead of time during cold weather so many more homes can be built during mild weather. Trusses span from one exterior wall to the other so interior walls can be moved at any time. Footings and posts are not necessary in the middle of the home except for 2 columns that support the loft beam. Building trusses also create jobs during the coldest time of the year. Only a few tools are necessary.
Wooden jigs align the boards so each truss is identical in size and shape.
Production is maximized if there are only a few standard sizes. Detailed engineered drawings show how they are built. Care must be taken, however, to carefully inspect each member of the truss for cracks and flaws. One aesthetic possibility is the use of a rounded, natural edge on the bottom chord that faces the living area. This design detail breaks up the monotony of a flat ceiling and becomes part of a beautiful, exposed wood framework.