Building Description Carysfort Lighthouse, Key Largo Florida

The Carysfort Lighthouse is a wave-swept, iron skeleton tower structure built in 1852 at Carysfort Reef, 12 miles northeast of South Channel, Key Largo, Florida. The lighthouse is within the boundaries of the Key Largo National Marine Sanctuary.

The foundation level of the structure consists of a central and eight peripheral vertical iron screw piles that describe an octagon, 50' wide, pile to pile. The construction rises from this level as a five-story octagonal pyramid to the light, the focal plane of which is 106' above mean low water. A two-story keeper's quarters is 24' above the foundation level, contained within a circular enclosure made up of 24 curved iron plates. The skeletal structure is braced with lateral iron girts and iron diagonal and radial tie-bars, resulting in a lighthouse that has needed only minimal repairs (1906, 1929, 1966, and 1975) over its 130 years of continuous operation as a first-class seamark.

Carysfort Reef consists of a hard upper crust, primarily elkhorn and staghorn corals, over a calcareous sand layer, a soil condition that virtually dictated the use of screw piles for the foundation construction. Based on a drawing copied by the Office of the Lighthouse Board in 1875, the screw piles used here consisted of 13" hollow iron shafts with a steel-tipped, 22" diameter auger-like bit of two complete turns. The nine foundation piles were literally screwed through the coral and sand crust to a depth of 10'. They were then capped with 4'0"D iron disks, each of which weigh, according to the drawings, 1692 pounds. The hollow shafts were used to house 9"D iron piles which extend the full depth of the screw pile and the foot-plates and rise to a height of 15'11". The eight peripheral piles are capped with cast iron angle sockets with 20" bulbous connectors that accept the iron lower chords, girts and radial beams of the skeleton. The foundation level of the lighthouse is cross-braced with 2"D iron ties with turnbuckles, the ties running from the outer piles to the central pile. The central pile is capped with a 3'D cast iron socket, semi-circular in section, with 12" deep, 4"D bored sleeves to receive the radial beams extending from the peripheral piles.

When built, the foundation level of the lighthouse was provided with a full deck consisting of 3" x 12" timbers bolted to 6" x 8" joists that rested on the iron girts and radial beams. At this time, only two wedge-shaped sections remain, one to either side of the due-north pile. The existing deck is later and is bolted to the iron structure. A 5' x 8' section of the northeast quadrant is missing.

The open space between the foundation level deck and the two-story keeper's quarters is 24' in height, and tapers in plan from the 50' octagon to one of 43'8" at the lower level of the enclosed space above. The iron peripheral piles are 29'6" long and extend through elaborate, 20" deep cast iron knees at the underside of the second floor, where they fit into 4' long cast iron sleeves. The piling above this level is reduced in diameter to 7" and continues above the roof of the quarters.

The central pile terminates in an 8'0" D cast iron socket that has an 11" deep outer ring connected to the 11" D central housing by eight spoke-like ribs. A collar above the center socket is cast to receive sixteen wood floor joists, which are let into the upper part of the collar and rest on iron stirrups.

Entrance to the two-story keeper's quarters is provided through a later, counterweighted iron trap door, which is reached by a ladder and a suspended stair from the deck below. Originally, the suspended stair had a catwalk and was served by a graceful iron spiral stair arranged around the central pile. The spiral stair was lost in a hurricane in 1929 and was replaced with a wood ladder. The existing steel ladder dates from the 1950's. The keeper's quarters is in the form of a truncated cone, with two rings of 24 curved iron plates at each level forming the exterior walls. The first-floor level is 17" above the bottom edge of the lower plates, the second-floor level 17" above the seam between the two rings. The lower level has a loading door in the north-northeast quadrant, seven rectangular window openings and sixteen 12" portholes (installed in 1906). The upper level has four full-height, double doors alternating with four double casement-type windows. All door and window openings at both levels have iron or iron-clad full-sized paired shutters, now spot-welded closed.

Photographic and documentary evidence shows that an exceptional cast and wrought iron balcony once surrounded the keeper's quarters at the second-floor line. A 5'0" wide walkway was enclosed by a 3'6" rail that consisted of a flat handrail and three-part wrought iron balustrade. The upper part of the balustrade was composed of scallop-on-scallop grillework, joined with ball connectors to 22" tall square iron balusters. The lower band, set 5" above the walkway, had an open, 6" tall diamond pattern. Records indicate that the balcony was in deteriorated condition in the mid-1950's and was unused. It was destroyed by Hurricane Donna in 1966. Drawings copied in 1874 from the original (1848) drawings show a second iron balustrade, along the edge of the roof of the keeper's quarters No other evidence of this feature has been found-the roof was rebuilt in 1929, obliterating any possible scars of the balustrade. The roof of the two-story enclosed section is constructed of iron plates, tapering from 16" at the stair enclosure to 6'10" at the outer edge. A rain collector that gathered water for the storage tanks in the first level was removed in 1975.

The interior of the lower level of the keeper's quarters is an open plan, dominated by a concentric ring of six large iron storage tanks (originally 4 water and 2 oil) clustered around the central column. The tanks are 5'0" high, create a circle 14' in plan, are flat-roofed and are provided with circular inspection plates in the upper part of each 600 gallon segment. The first floor is constructed of three concentric rings of iron plates, the plates bolted together on the underside of the floor. The outer ring of plates does not meet the wall, with 8" open space between the foor and exterior plates. This may indicate that the interior of the lower level was originally finished in some fashion, as shown in drawings dated as late as 1950. No evidence, architectural or otherwise, has come to light to document this treatment, and the walls are now protected with a painted-on mastic compound. The open space continues through the second-floor cavity, permitting air to circulate from below the lower floor to and through the roof of the two-story construction. The eight peripheral piles are inset 9" at the floor level so that they would be clear of any interior wall treatment, and terminate at the exposed underside of the rolled iron plate second floor at heavy cast rion knees. Access to the upper level is by a ladder-stair constructed of steel channels and diamond plate treads, obviously latter but probably replacing a similar stiar of wood. Ceiling height in the lower level is 6'6".

The upper level, which was the keeper's apartment, retains virtually all of its 1852 fabric, with only minor alterations. The plan remains as one of four essentially equal-sized spaces set off with full-height partitions at the cardinal points, except that the northerly wall is 15 degrees east of north. The walls running from the central enclosed stair that reaches the light tower to the north and to the east are provided with double doors, each leaf four raised panels in design (Grecian ovolo sticking) with molded architraves. Both units remain. The walls running to the south and the west have single, four-panel doors centered in the wall originally. The door in the west wall has been moved towards the central stair enclosure. This enclosure had a similar single door, now removed. There is a double door in the exterior wall of each of the four spaces, each leaf with two glazed panels over a single raised panel, and each space has a window consisting of paired casements, three lights in each sash. The doors extend into the room areas in enclosed vestibules, with a built-up threshold and floor, with a screen door at the outer edge of the jamb liners, and paired iron shutters. The doors opened to the now removed balcony.

The exterior walls are sheathed with tongue and groove paneling, which is also used at the stair enclosure. The peripheral piles along the exterior are cased and the cross partitions and ceiling paneled. The partitions have 10" wide recessed panels framed with applied ogee sticking, separated by 4" stiles. The ceiling has the same recessed design with the panels radiating from the stair to the outer walls. Each of the four rooms also has a projecting built-in closet, with four-panel doors and paneled walls similar to the cross partitions.

Mid-20th-century alterations include, in addition to the relocation of the door in the west wall, the construction of a series of frame partitions in the southwest quadrant. The southerly partition encloses a pump room (the pump and a water heater remain), with succeeding partitions setting off a bath and a small galley.

The stair to the light is enclosed in an 8'7" iron shaft that extends 38'3" above the roof of the quarters to the light tower floor. The interior of the enclosure from the second-floor level to the ceiling is sheathed with the same beaded, tongue and groove siding as used in the exterior walls. The shaft has an interior diameter of 7'2" with a 10" central column, resulting in 31" long, wedge shaped treads with a 7 1/2" rise. Originally, all treads were iron, but approximately 25% have been replaced with wood. The shaft is constructed of curved iron panels, bolted together at the inside, continuous flanges. There is a rolled iron door providing access to the roof of the keeper's quarters, with a series of eight portholes for light and air. The center column terminates at a cast iron socket that has the appearance of a Tuscan capital. Two feet in diameter with an 11" hub, the socket has eight sleeves for the floor joists of the light tower, which rest on the edge of the iron wall plates.

The skeleton structure between the keeper's quarters and the light tower repeats the eight peripheral piles and central column. The outer piles are 6"D to a point 20' above the roof line of the dwelling, then are reduced in size to 5"D.

The cylindrical light tower is 11'8" in diameter at the interior, two full stories in height. The lower level is 6'11" to the underside of a 25" deep catwalk that surrounds the lantern, the catwalk reached by an iron ladder-stair. The interior walls are sheathed with beaded paneling to the catwalk. The iron housing for the lantern is circular in plan, with one quadrant cut away to provide service access to the light itself. The housing is cast in a decorative paneled pattern. The rotator installed in 1852 and electrified in 1926 remains, but the lantern is now fixed in place. This lower level of the light tower was partially enclosed in 1926 to house a generator and later the storage batteries that now power the light.

There is a low, solid panel above the catwalk in the upper level of the light tower, with three rings of glass stacked above it at the exterior wall, all set into iron vertical ribs and frames. The ribs support a flattened conical roof. The low paneled area above the catwalk has a series of cast iron vents, much like scuppers in a vertical position When built, the Carysfort Lighthouse had a fixed light, but after only four months, in July 1852, it was provided with a first-order revolving Fresnel lenticular illuminating apparatus constructed in Paris by Henry Lepaute. The lens consisted of sixteen panels with an inside diameter of 6' 10 1/2". It was lit by eighteen oil lamps arranged in two concentric rings of eleven and seven lamps, and had 21" reflectors. The light was classified as a dioptic light (the light passing through the glass lenses and prisms, which concentrated it into parallel beams). At some point near the turn of the century the light source fuel was changed from oil to kerosine (with four 30" tanks strapped below the floor of the lower level of the keeper's quarters), and as mentioned, was switched to electricity in 1926. The light was officially de-manned after WW II and fully automated, served first by underwater cables from Key Largo, which soon failed, and later by storage batteries. Most of the original cast iron light housing, lenses and reflectors, and other parts of the lamps remain and are in good condition. Iron cresting along the edge of the roof of the light tower was destroyed during the 1966 hurricane.

Records of the Lighthouse Board for 1852 describe the color scheme of the structure, with the piles and other members of the skeleton painted black, the exterior walls of the lighthousekeeper's quarters and the light tower red, and the windows and doors white.