Characterization and assessment

The El Morro Castle in San Felipe is a historical fort in the north of Puerto Rico, which is part of the defense system of the bay of Old San Juan, together with the San Cristobal Fort and its walls, on which construction began in 1766. This site was inscribed on the ^{UNESCO list of World Heritage Sites (WHS) in 1983} as part of La Fortaleza and San Juan National Historic Site, in Puerto Rico. This designation was based on criterion VI,⁵ for its colonial military architecture in America and its role in the defense of San Juan between the 16^th and 20^th centuries (World Heritage Centre, 2024). Nowadays only those elements closest to the coast remain, including the northern wall, both forts, the governor’s mansion and San Juan gate (Figure 1). In addition, on the northeastern bastion of the San Felipe fort, on a promontory (morro) to the east of the bay, there is a lighthouse.

(Source: National Park Service, World Heritage Centre, 2024)

Figure 1 Site plan of La Fortaleza complex and San Juan National Historic Site in Puerto Rico at the time of its inscription on the World Heritage List in 1983. 

Historical background

The history of the El Morro Lighthouse in San Juan is marked by several construction phases and interventions. According to the Central Archives of resource records for this heritage site protec ted by the National Park Service (NPS), it was built in 1846, and is considered the first in Puerto Rico. Created prior to the implement ation of the maritime lighting plan put forth in 1869, which sought to install 15 lighthouses around the island to protect strategic ports and commercial routes between Europe and America, its trace can still be seen in the fort’s southwestern bastion. The second building (Figure 2) of 1876, also had an octagonal plan with a clinker brickwork base, and a 174-feet-tall (53 meters) metal tower ^{(National Park Service, 1978-88)}.

(Photograph: Feliciano Alonso, 1985; source: https://www.geoisla.com/2017/03/antiguo-Lighthouse-del-castillo-san-felipe-del-morro-circa-1898/)

Figure 2 Photograph of the Lighthouse in 1895. 

As described in NPS expense records (1999, pp. 98-165), in 1900, eleven years after Spain transferred control of Puerto Rico over to the United States, a second level was added. At first, a dwelling for the lighthouse keeper was not considered, as it was expected he would live in San Juan city and travel to the Lighthouse when necessary. In that building, which was damaged during the Amer ican invasion in the Spanish-American War, the original plan was to reconstruct or repair the metal tower, however, due to administrat ive problems and the loss of rescuable elements, it was decided to build a third light tower. The fourth and final construction phase corresponds to 1908, when the second level was rebuilt due to its bad quality and early deterioration.

During the last quarter of the 20^th century, concern arose regarding the Lighthouse’s state of conservation. Despite having been reported as a conserved building with regular maintenance, it can be seen interventions were carried out in response to specific deteri oration, rather than following a preventive conservation strategy. In 1991, a restoration proposal was relaunched, which marked the last significant intervention of the Lighthouse, although challenges in management of historical heritage and its conservation can be noted throughout its history ^{(National Park Service, 1991, pp. 1-10)}.

Geographical context and the environment

The geophysical context of Puerto Rico originated from the collision of two tectonic plates, the North American and the Caribbean; this gave rise to both the formation of the Antilles and the Puerto Rico Trench, the deepest point in the Atlantic. Old San Juan islet-where the geology includes artificial fillings, beach deposits, and near ground level aquifers and alluvium-has diverse topo graphy (Figure 3) and lies on a coastal plane at sea level; however, the El Morro Castle in San Felipe rises on a strategic hummock, which was used to build a fort and the location of the Lighthouse ^{(Quiñones & Torres, 2005, p. 4)}.

^{(Source: Quiñones, F. and Torres, S., 2012, p. 2)}

Figure 3 Topological diversity map of Old San Juan in Puerto Rico. 

Regarding climate, Puerto Rico is warm and humid as a result of its location in the Caribbean, with a maximum temperature that fluctuates between 26 and 32 °C (79 and 89 °F), and a relative humidity above 70% all year long. Temperatures vary moderately throughout the year, the warmer months (August and September) at 32 °C (89 °F), and the coldest (January) at 26 °C (79 °F). Relative humidity is generally high, with a peak in October (76.9%). San Juan experiences high sun exposure, with an average of 13.2 hours of daylight in June. Precipitations are highest in August and lower in March. The prevailing winds come from the northeast and southeast trade winds, with a windy season from June to August; the region is vulnerable to hurricanes from June to November ^{(Quiñones & Torres, 2005)}. Regarding flora and fauna, the coastal zone has plants associated with mangroves, and microflora can exist due to climate conditions.

Typology and morphology

The El Morro Lighthouse in San Felipe illustrates the evolution of lighthouse technology throughout the 18^th and 19^th centuries. During the 18^th century, these lighting systems relied on simple mechanisms, such as weights, springs, lenses, and lamps with eclipse systems (Figure 4).

^{(Source: Sánchez, T., 1992)}

Figure 4 Nineteenth century Spanish design of the lighthouse to be built on Maniguin Island, Philippines. On the sketch one can see the use of eclipse systems with Fresnel lens. 

With modernization in mind, Spain established a Lighthouse Committee in the 19^th century, which adopted building materials used in other countries. In this process, the Lighthouse structure underwent a significant change: going from the original conical masonry shaft to a cylindrical metal shaft and tower, which were made by the United States to support the lantern. Various fuels have been used for its operation throughout its history, from carbureted hydrogen to incandescent lamps, xenon gas, mercury or halogen, with electrification in 1915. The internal structure of the Lighthouse is made of iron, whereas all the external parts and frames are made of bronze and the dome of copper plates. Meanwhile, the covering, for its part, is made of glass, and the light towers of the first three classes have a platinum-tipped lightning rod.

In terms of morphology, El Morro Lighthouse in San Felipe presents ornamental elements which display the influence of Neoclassicism and are reminiscent of Neo-Mudejar style. The symmetry of the façade of the second section, including the windows and shades, together with the use of cornices that frame the building and its openings, establish a characteristic architectural language of these styles. One can also see valances, accents on the windows with semicircular or segmental arches in the decoration and moldings, which are repeated on the interior façades. The use of box profile merlons in the building’s crenelated parapet symbolizes its role of protection; the concrete sentry boxes, which were added later, emphasize its military nature. The ground floor displays influence of its early Spanish period, through the width of its walls and the quality of the bricks, whereas the lantern, made of cast iron and glass, dates back to the Industrial Revolution (Figure 5).

(Drawing: Sarahí Soriano and Rodrigo Sáinz, 2019)

Figure 5 Schematic of El Morro Lighthouse in San Felipe (East elevation) indicating the Neoclassic and Neo-Mudejar elements. The dotted lines represent the symmetry of some of its façades and/or elements. 

Construction systems and materials: walls, mezzanines, covers, metals, woodworks, and fittings

Throughout its history, the Lighthouse in the El Morro Castle in San Felipe presents a structure with a great variety of building materials and construction techniques, according to sources consulted in central archives, among them a report of general information on the lanterns and a memoir on the building’s restoration in 1978. The base, perched on ribbed vaults in the upper battery of the castle, has a volume of 79 m³, and the ground level floors comprise a hydraulic cement underlayment and tiles from the Canary Islands. Inside, the staircase that connects the ground level with the first level corresponds to an addition during the fourth phase and is made of reinforced concrete with a finish of hydraulic cement; the walls are apparently covered in gray vinyl paint. However, in situ observation, backed by documentary data from the NPS, reveals that there have been variations in the construction materials used during the different building phases. The octagonal base ground floor pertains to the oldest phase and consists of masonry using sizable red clay clinker bricks, made in Spain, laid with lime and sand mortar. On the other hand, the quadrangular base first level, corresponding to the fourth phase, used industrial American bricks laid in a cement and sand mortar. The fittings include hydraulic systems with lead pipes, electric systems with galvanized conduit tubes, and the LED illumination is powered by solar panels installed on the rooftop of the building.

Morphological analysis: functionality and context

The formal analysis stresses the integrity and authenticity of the Lighthouse’s shape, which mirrors Puerto Rico’s historical transition from Spanish dominion to becoming an Associated State. Certain original elements, such as the glass panes of the lantern and the lighting mechanism, have been replaced by more modern versions. The current state of conservation enables it to remain in operation given there is no risk of collapse. Nevertheless, deterior ation in the structure and finishes have led to visits inside being canceled due to safety reasons.

The building has lost certain elements of its original system, although a significant part of the early electric infrastructure is still conserved in situ. It is considered important that this Lighthouse continue to fulfill its function as part of the marine signaling system, because this gives continuity to the building and fort’s histor ical value. On the other hand, the contextual analysis stresses that the heritage asset’s location within a 16^th century fort hinders an adequate evaluation of its foundations, owing to the constant flow of visitors. Physical damage to the building is consistent with the quality of the materials, which manifests in the various degrees of deterioration in each of the stages. For example, the 19^th century Spanish red clay clinker bricks, measuring roughly 28 x 21 x 7 cm,⁶ have a dense composition, while the American industrial red clay bricks are lighter, more porous, less dense and smaller (2 x 4 x 8”). When comparing both types of bricks, now exposed due to lack of coating,⁷ the American blocks present greater erosion and efflorescence than the Spanish ones.⁸

Likewise, the marine environment, which can be very harsh, increases the erosion by friction on masonries, as well as corrosion of metallic elements and development of efflorescence on floors and walls, given the humid and saline environment. Moreover, constant precipitation and extreme temperatures have a strong impact on the deterioration of the building and the structural integrity of its materials.

Methodology

The following methodologies were used in this project: the OVO (Organized Visual Observation) method by ^{Pedelì (2014)}; the guideline indicated in The Conservation Plan by ^{Kerr (1985)}; the regulations in The Burra Charter, ^{ICOMOS (1999)}; Ciro ^{Caraballo’s (2011)} method to identify systems of values and attributes; the matrix proposed by architect Rubén Rocha (2018) to analyze the architectural and structural components of the building; as well as the De Angelis (1982) and ^{Carbonara (1990)} method for both the architectural and damage surveys. The comprehensive methodology can be summarized as follows:

Damage analysis

Damage to the Lighthouse is predominantly related to lack of maintenance, visible in the building’s finishes, both interior and exterior. These have been caused by water infiltrations in the cover and structural problems resulting from the geometry of thebuilding, which has led to cracks and fissures of cantilever elements. Furthermore, factors of the coastal environment, which promote corrosion of metal objects, the emergence of efflorescence on walls and weathering of masonry elements. Additionally, through in situ observation we identified that the materials used during the different periods did not react to the environment in the same way, determining that (Figures 6 and 7):

(Drawing: Sarahí Soriano and Rodrigo Sáinz, 2019)

Figure 6 Schematic of the damage survey of El Morro Lighthouse in San Felipe (East elevation). 

Figure 7 Damage characterization of El Morro Lighthouse in San Felipe 

Photograph	Description	Location
	Exfoliation of iron elements due to humidity	The metallic elements of the lantern on the roof, mainly in those integrated during the 1991 intervention. Likewise, it is observed on interior lamps and the staircase connecting with the lantern
	Stains and runoff from elements of iron rust onto walls and floors	On walls at the footing of the lantern and on the second floor, where the structural metal elements of the mezzanine are supported. Especially at the split-level between the main room on the second level and the corridor
	Filth and accumulated rubbish as the lighthouse is unoccupied, its use as a storeroom, and lack of maintenance	Besides garbage, a great deal of dust is observed in all interior spaces of the lighthouse. There is rust on the floors due to infiltrations and pieces of wall covering and iron that have fallen from the covers
	Loss of paint and crumbling of material due to accumulation of humidity and salt formation. The waterproof paint, on finding an access point in the masonry, causes bulging	On interior and exterior walls, at no specific height, present on the three levels/stories
	Cracks and fissures in walls caused by settlement of the building, geometry problems, inadequate material, and an increase of structural metal elements	In the inferior and superior parts of structural openings as well as in overhung elements; particularly large ones correspond to the overhang of the stairwell
	Cracks and fissures on cornices as a result of settlement of the building and deficient geo metry	Mainly in the center of structural openings and overhanging elements on the second story, the largest ones being those in the stairwell
	Loss of paint on walls due to dampness and accumulation of salts which has led to crystallization, in addition to constant humidity and wind erosion	On all the building’s façades, the one most affected is the southeastern, corresponding to deterioration of the first lighthouse
	Loss of material in brickwork resulting from salt crystallization and wind erosion on walls built during the 20th century	Exclusively in sections built during the early 20th century phase: upper story and inferior part of the staircase and access corridor
	Salt efflorescence on interior and exterior walls caused by atmospheric moisture and salinity as well proximity to a semicircular concrete structure (Figure 6)	Mainly on the lower parts of interior and exterior walls. On the ground level these are more evident and larger outside, whereas on the upper floor there are more on the interior walls but smaller in size

(Compilation: Sarahí Soriano and Rodrigo Sáinz, 2019).

System of values for the Lighthouse

The building’s identified values are based on the analysis of retrieved archival data and examination of the social context it is set in. As a historical record, the Lighthouse (heritage asset) bears witness to the fort’s evolution, maritime history, and the island’s development. Through historiographic analysis, we identified the numerous modifications it has undergone to become the building it now is, as well as the different conflicts that it has lived through. Its shape has been part of the El Morro Castle in San Felipe since before the Spanish Crown proposed the lighting project for the island at the end of the 19^th century. The fort has had a light signaling system since 1846, however the current edifice corresponds to the 1908 construction, which took advantage of elements built in 1876. Furthermore, the building is part of the history of the Caribbean, being the first lighthouse on Puerto Rico and the predecessor to its coastal lighting system ^{(NPS, 1992)}.

Throughout its different construction phases, one can see the evolution of lighting systems in the Caribbean, along with lighthouses built on the island which are like each other and correspond to the same construction system and the currently observed style ^{(Mari, 2009-2013)}. By means of historiographic analysis, we know the previous design that predated the current construction was different, since the construction system was adopted based on a metal structure that was already in the fort since the first version.

If the Lighthouse is not intervened, its load-bearing structure of walls and enclosure will be further compromised in the western façade zone, hence they could both collapse. Likewise, if the masonry, eroded grout, and mortar overlay on the southern façade are not replaced, these elements could subsequently present struc tural damage. Although the greatest deterioration is found in elements built in the 20th century, this can still cause future collateral damage. In other words, if the roof collapses, the 19^th century lantern will too, and the historicity of the 19^th and 20^th centuries would be compromised. Beyond its role as an attribute of outstanding universal value (OUV), its conservation is important because the Lighthouse is a major element of historical Old San Juan’s urban landscape. Not only is it the tallest building in the fortress, its color contrasts with the other materials on the site. Its distinctive presence is considered part of the local identity and the collective imagery of its residents and visitors, generating stories and awakening curiosity about the building. Likewise, the fact that it is currently in use as a lighthouse enables the system of fortifications to remain alive in the everyday life of neighboring social actors.

The values identified through this fieldwork and academic research reveal that, being the first and most important lighthouse in Puerto Rico, it witnessed the evolution of the defense system up until the 20^th century, demonstrating the site’s historical and military continuity. The latter being one of the elements for which Puerto Rico’s System of Fortifications was inscribed in the World Heritage Sites list by ^{UNESCO, in 1983}.

Furthermore, it provides a distinctive and identifiable element to the cultural services, as well as an image that can promote the Old San Juan. Hence, we believe the conservation of this building represents an essential part of safeguarding Old San Juan’s maritime identity, as it is the starting point for the island’s development and its history.

Theoretical basis for a comprehensive intervention

The Lighthouse in the El Morro Castle in San Felipe, though relat ively young, has elements from different periods which reflect the political and cultural history of Puerto Rico (Figure 8). Its evolution fits the concept of first and second history following the context of ^{Brandi’s Theory of Restoration (1995[1963], p. 17)}, in which each development phase has its own importance. The proposed intervention was based on the notion that the building must preserve its original purpose, as an element of coastal signaling,¹⁴ as well as its stability; and that access to it must be permitted to enhance its historical value. It states that modifying its current location would be contradictory to the conservation of its values. The Venice Charter ^{(ICOMOS, 1964, p. 2)} stresses the importance that a monument be linked to its history and location, and that its transfer should only be considered under extraordinary circumstances. This intervention seeks to recover the building’s stability without altering its aesthetic appearance nor its historical and cultural context. Its focus is conserving the essence of the monument, avoiding unnecessary changes.

(Photograph: Sarahí Soriano and Rodrigo Sáinz, 2019)

Figure 8 Photograph of El Morro Lighthouse in San Felipe. 

The proposal is based on respecting the authenticity of each of the asset’s historicity’s and is justified by considering the conservation not only of the Spanish period, but also those interventions carried out during the 20^th century. Although the main proposed intervention is the stabilization of the load-bearing walls and maintenance of the cover, preventive conservation is crucial to guarantee the preservation of its authenticity and historical riches.

Considering the diversity of the building’s construction phases and its location in a historical asset with its own value, whose history is complemented by the Lighthouse, it is important to take care of the context in which it was built and the element itself. The dialogue between the different stages is a key factor in the signific ance of both the edifice and the general ensemble, including the relation that exists between the phases and the original elements. Hence, each part bears witness to its period and known characteristics, while revealing the evolution of the asset, Puerto Rico’s political history, and the development of technologies for coastal surveillance.