*4.1. Phase 1. First Step: Original Condition*

To reconstruct the original building, the work team searched for documentation in the Simancas Archive and at town hall, with practically no results. Basic graphic documentation was located in a publication on flour factories in the province of Valladolid; the document provided an initial orientation for the survey of the building [31].

As described by de la Red [31], stone, wood, brick, and ceramic tiles are, among others, the constituent materials of this factory, present in the foundation, interior structure, enclosures, and roof, respectively (Figure 4). Stone is used as the structural material, forming the foundation of the building, which has 1.20 m-thick walls. In the lower part of the building, three water channels run through arcades that are built with ashlars and continually exposed to erosion. In the interior structure, wood is used by means of insulated supports to support the weight transmitted by slabs of the same material. These supports are called "piedroits", which usually rest on a stone block and, at the top, are finished off with a wooden capital. However, wood acquires more importance in the architecture of the flour factory in the slabs for different floors. The beams are combined with filler ties, and planks are nailed on top, leaving the wooden floors visible. The roof, which is also made of this material, is defined as a row-to-row. Its use is rare because balance can be an issue; although it can be supported on wing walls, the central row or beam is generally supported by pairs of crossbeams. Wood is also used in the corbels of the roof eaves [31].

Aided by building documentation, the first step of the work methodology involved reconstructing the original condition of the building; notably, that there was no annex (Figure 5). The annexed warehouse was a later addition to the initial construction, which helps to differentiate the styles between the two parts of the complex. This addition is also a reflection of the probable changes that the then-established company underwent, assuming an increase in production that required an increase in warehouse surface.

**Figure 5.** BIM model of the body of the factory: first phase, original condition. (**a**): Front view; (**b**) Rear view.

#### *4.2. Phase 2. Second Step: Current Condition*

Exhaustive fieldwork was carried out by performing topographic measurements to obtain real measurements of the building, and dimensions of the surrounding terrain, to perform BIM of the current condition of the industrial building.

Currently, more than half a century since its closure in 1961, the old flour mill "La Julita" is in a state of ruin and abandonment. Comparing the current and original conditions, many elements of its composition have been modified or destroyed by the passage of time. First, the terrain around the structure has undergone severe transformations that have practically covered the three canals, leaving only the one closest to the river open; however, water does not pass through them (Figure 6).

**Figure 6.** BIM model of the body of the factory: second phase, current condition. (**a**): Front view; (**b**) Rear view.

Likewise, the first-floor windows are bricked, and the rest of the floors are empty openings in which, in some cases, part of the old wooden frame persists; furthermore, many of the brick Sardinia-style lintels have disappeared (Figure 3).

Compared with the brick, the exterior stone walls have not deteriorated much, due to the inherent strength of the material itself. The interior wood structure is practically destroyed, the floor slabs no longer exist, and only some wood structures remain connected to the exterior enclosures, interior partitions, and the structure of the roof, which has nearly collapsed entirely. Due to the extreme deterioration of the structure, there has been some attempt at reinforcement, due to the presence of steel beams that protrude at the height of the second floor.

In this phase, the condition of the building was modeled as it currently exists (Figure 6). According to the phase modeling, a warehouse addition was built after the initial construction, which allows a comparison of the difference in styles between the two parts of the industrial complex. This addition is probably a reflection of the probable changes experienced by the company, assuming that there was an increase in production that required an increase in the storage area.

#### *4.3. Phase 2. Third Step: Demolition Stage*

Demolition is another phase recommended for conservation projects that aim to rehabilitate the building for new-use development. This phase aims to show the condition of the building prior to construction for new-use development. In this case, the model shows the maintenance of the exterior structure, while the entire interior, with the exception of the transverse load wall, has been eliminated due to its state of complete ruin (Figure 7).

**Figure 7.** BIM model of the body of the factory: third phase, demolition stage. (**a**): Front view; (**b**) Rear view.

#### *4.4. Phase 3. Fourth Step: Good Practices*

Finally, the last phase corresponded to the application of the rehabilitation proposal. Before beginning the process proposed in this work, it was necessary to establish an objective and contrasting approach to aid in decision making for this type of industrial heritage intervention.

As discussed in a previous section, one method of restoration with great international prestige and consolidation is the approach of the Italian Camillo Boito. In the Conference of Architects and Civil Engineers of Rome in 1883 [57], Boito presented his ideas on how the restoration of cultural assets should be carried out through the "Charter of Restoration", bearing the eight points of Modern Restoration, the predecessor to Scientific Restoration (Charter of Athens 1931). Its maxim was to "consolidate before repairing and repair rather than restore" to conserve, to the greatest extent possible, the peculiarity and originality of the good to be intervened.

The difference in styles between the old and the new, the difference in materials used in the work, and highlighting the authentic value of the building during the intervention are some of the eight points designed for all types of cultural property, with their own characteristics. Therefore, it is necessary to apply the eight points to the reality of this building and its peculiarities and possibilities.

This last phase of the intervention not only allowed for the comparison of different design proposals, but also verified decisions made and observed possible execution errors through BIM software used to simulate the real conditions of the building, and to identify possible conflicts in the project and the consequent construction. Regarding decoration modeling, the building of this practical case needs a 3D model that is less complex than other studies [58].

From the extensive study performed on the condition of the factory and its surroundings, as well as the circumstances that define and condition it, a series of guidelines were extracted that guided both the choice of the new use and the design proposal for its rehabilitation. Among the ideas that were established as objectives to be met, which we understand as best practices in the treatment of industrial heritage, we highlight as fundamental those that showcase the past history of the building and what occurred inside, as well as the context in which its activity developed; maintain the industrial character of the building and all its elements; ensure, in the new use and related rehabilitation process, the responsible use of resources contributing to the sustainable, social, economic, and environmental development of the environment; highlight the authenticity and originality of the building in contrast to the new use, which is defined by a different style and materials; and finally, protect the environment in which the building is located and its unique natural characteristics (Figure 8).

The process of a loss of function of the installations and productive infrastructures occurs rapidly for industrial buildings. When the factories cease to be productive, they also cease to be profitable; therefore, in most cases, adequate maintenance was not carried out for their conservation because no profit was obtained. When the industrial complexes that grew under the protection of industrial activities fell into disuse, they also fell into neglect. Factory buildings, as productive spaces that house obsolete productive activities, are disappearing and progressively falling into ruin. Therefore, it is a challenge to find new uses to which these goods can be associated [3].

Concerning the case studied here, Simancas is a municipality located approximately 14 km from Valladolid. It is a very important historic locale because of the General Archive of Simancas.

Another very valuable aspect of the municipality, from the environmental point of view, is the great ecological value of the Pisuerga River. The "La Julita" flour mill sits on the right bank of the Pisuerga River, very close to the confluence with the Duero River, which allows a reactivation of the use of the motive power of water for the energy supply to the building, contributing to sustainable development.

Consequently, to define a new use for the factory and therefore its new identity, the capacity of the factory to bring wealth to the community, both economically and culturally, was taken into account. This new use, as a priority, should change the negative significance that the community has regarding this building and its circumstances. To this end, a solution was sought within the environment, identifying a place with greater and better significance for the community and addressing a need not yet covered.

(**a**) (**b**)

**Figure 8.** External renderings (BIM) of the proposed preservation. (**a**): Rear view (**b**) Front view; (c) Plant.

Finally, the new use was defined as a residential collaborative space whose objective is the promotion of research and collaborative work among professionals of all sciences, to promote the implementation of recovery projects and revaluation of industrial heritage buildings and goods. The residence plans included accommodations for researchers in connection with the General Archive of Simancas for consultation outside of its official facilities. Therefore, the objective was to establish a center for the creation of conservation and innovation initiatives in the field of industrial heritage protection. With this new use, the already known and integrated coworking concept can evolve into another context: Research.

Therefore, from the study performed on the condition of the factory and the environment in which it is located, as well as the circumstances that define and condition the factory, a series of results have been extracted as requirements that must guide the implementation of the new use as well as the design proposal for its rehabilitation:

• Spaces will be established to show the past history of the building and what occurred inside it, as well as the context in which it developed its activity. For this purpose, on the ground floor, a large part of the space will be dedicated to an exhibition of the past life of the building, with all its circumstances and characteristics, and the historical and economic context in which its activity developed. Likewise, space will be provided on each floor for sample activities that were carried out on that floor to assimilate each space with its function and original condition and contrast it with the new use.


Thus, the intervention focuses on the following aspects:


**Figure 9.** Interior rendering (BIM) of the proposed new-use development.

One of the most important requirements to which all others are subject is that of, through design decisions, ensuring accessibility to all types of people and nondiscrimination of any group, as well as their safety within the premises. To this end, the pertinent regulations, stated in the Technical Building Code as applied to Architectural Restoration works, through the Support Document for the Basic Document on Use and Accessibility Safety DB-SUA Code: DA DB-SUA/2 "Effective adaptation of accessibility conditions in existing buildings" and Basic Document SUA: Use and Accessibility Safety [59], were taken into account in this regard.

The design decisions that mostly affect the interior of the building are the requirements referring to the spaces and users' interaction with them. These are enunciated in the so-called conditions of accessibility, which in turn are divided into functional conditions (accessibility on the outside of the building, between floors of the building, and on the building floors) and accessible elements (accessible accommodations, reserved spaces, accessible bathrooms, fixed furniture, and mechanisms). Special attention was paid to fulfilling the specifications related to spaces and construction elements such as bathrooms, kitchens and dining rooms, public spaces, entrances, ramps, points of care, switches, and furniture.

This rehabilitation proposal brings together, on the one hand, the effective exercise of an innovative design that is totally appropriate to the space and respectful of the legacy of a historic building. On the other hand, it achieves the total protection and conservation of a space and its surroundings through a process of valuation, not only of its constructive characteristics and its potential as a container, but also of all the experiences that were developed within it and that currently make up an equally valuable and necessary heritage to be preserved and promoted for its full protection and promotion.
