The planning of a restoration should be always aware of the material consistency of the artwork.

The collection and the analyses of the previous historical data may not be the sole basis for a good project; it is necessary and always desirable to make a direct evaluation of the monument, by the sight and the tact of the designer.

On sigh it can be analyzed the form and the architectural composition, the urban framing, the architectural and constructive details, the constitutive materials and the forms of macroscopic alteration present. By the touch can be recognized special materials, their processing, some acting forms of degradation: the phenomena of detachment from the supports of the plaster wall, for example, are detected by tactile auscultation acoustic (knocking).

For the monuments of considerable size is not possible to conduct a scrupulous investigation of all surface being on ground floor. In these cases should be used a basket lift or, for the works of some importance or delicateness, a fixed or mobile scaffolding. The direct investigation up close, it is always important: although it may be a preliminary high cost, it is essential for a good design, because it can provide most of the action without "surprises" during the restoration phase.
Such visual investigation should be done by specialists in the different fields of the discipline of restoration: coordinated by the architect, will be present the engineer for the structural problems, the geologist, the chemist and biologist for the microscopic analysis of deterioration, the restorer for the hypotheses of intervention, the art historian for the match between the documental and material data.