The term “building envelope” generally refers to the roofs, walls, and below grade components of a building. The roof is a very complex component of the building envelope and according to the International Building Code is in fact a structural element of a building.

Manufactured and field fabricated parts are assembled in the field by roofing companies. The skill level of the persons building a roof are widely varied from unskilled to highly skilled. The final product depends on good quality materials installed properly. Supervision of the field work by the construction associates is also a variable that ranges from fulltime, to sometime, to none.

Fulltime independent observation (inspection) is a viable and accepted method of assuring the final quality of the roof. Due to the cost and desire to keep construction expenses down, this is not the most common method of quality assurance exercised.

As in most elements of construction, testing protocols have been developed to monitor the quality of installation either during or after the construction is complete, or both. Think for example of the field testing of concrete, steel, and most other construction materials commonly used on projects to assure quality.