The major work is the set of books for the resumption of sustained efforts ongoing by construction (the charges received and weight of the building) and temporary (wind, earthquakes, etc..) And all that strength, stability of the building (main walls, columns, floors, roofs, etc..).
 In construction, the shell will complete the second work, which consists of all other works based on it: insulation, walls, siding, fireplaces, fixtures, equipment, etc..