CABRILLO Historic Structures Report

Definitions

The National Park Service has assigned each structure a proposed ultimate treatment. These include Preservation, Restoration, Rehabilitation and Stabilization. The National Park Service has defined these treatments as follows. Also see the Appendix for the Secretary of the Interior's Standards for Preservation, Rehabilitation, and Restoration.

Reconstruction: Depicting, by means of new construction, the form, features, and detailing of a non-surviving structure to replicate its appearance at a specific period of time and in its historic location. Features within the period of significance are preserved and deteriorated features are repaired, or replicated.

Restoration: Restoration accurately presents the form, features, and character of a historic structure as it appeared at a specific period. It may involve the replication of missing historic features and removal of later features, some having cultural value in themselves.

Rehabilitation: Defined as the act or process of making possible a compatible use for a property through repair, alterations, and additions while preserving those portions or features which convey its historical, cultural, or architectural values.

Preservation: Applying measures necessary to sustain the existing form, integrity, and material of a historic property. Deterioration caused by natural forces and normal use are arrested and retarded. Maintenance and stabilization of the material are means to preserve the structure.

Stabilization: Acting to render an unsafe, damaged or deteriorated property stable while retaining its present form.

Building Recommendations

The following recommended treatments are included to help park staff accomplish the ultimate treatment for each structure at Cabrillo National Monument. In addition to the specific recommendations that follow for each structure, all projects must be documented before, during and after work takes place. Minimally, such documentation should include clearly labeled before, during and after photography; a project description including date, scope and cost; and any drawings or other construction documentation used to guide the project. This information should all be stored in one central archive location.

Cyclical maintenance is also recommended for all structures. This includes: periodic inspections; removal of debris, invasive vegetation and ground infill; monitoring of erosion and subsidence; and verification that structures closed to the public remain securely locked to prevent further vandalism. The seaside location demands especially that routine maintenance include monitoring of metals and concrete, materials especially prone to deterioration in a marine environment.

Painting with approved historic colors is recommended for many of the structures. Paint schemes for each structure are to be based upon building-specific paint analysis and research. As described in the preceding Conditions and Recommendations section, paint analysis should be conducted prior to paint removal to avoid destroying historical evidence. Final color selection should be approved by an historical architect or conservator.

ARMY RADIO STATION: REHABILITATION

• Apply finish paint to new door and windows.
• Monitor soil surrounding structure.
• Replicate missing portion of pipe railing at stairs.
• Remove or paint over non-historic graffiti at rear façade.
• Consolidate rotting wood at door and window frames.

ELECTRICAL CONNECTION BOX: RESTORATION

• Clean and coat exposed reinforcing rod.
• Patch spalled concrete.
• Remove rust from all metal elements. Abate or encapsulate lead-containing paint. Treat metal with rust inhibitor, and paint with approved historic colors.
• Paint with approved historic colors.
• Replace eroded earth to cover foundation. Halt further soil erosion.

SEARCHLIGHT SHELTER NO. 15: PRESERVATION

• Repair spalled concrete.
• Repair cracks in concrete if greater that 1/16".
• Remove non-historic graffiti from concrete.
• Investigate water infiltration to retard efflorescence.
• Replicate missing metal roof vent in-kind.
• Replicate original metal entry hatch in-kind.
• Remove rust from all metal elements, abating lead paint hazard, treat with rust inhibitor, paint with approved historic colors.
• Consolidate or replace in-kind deteriorated wood curbs under roof.
• Paint with approved historic colors.

SEARCHLIGHT SHELTER NO. 18: RESTORATION

Note: Exterior painting occurred in early 1999. We do not know the extent of testing, cleaning and preparation that occurred prior to this work. Therefore, we suggest monitoring this structure for signs of recurring cracking, spalling and corrosion.

• Stabilize hillside erosion as best determined by soils engineer and park ecologist.
• Review vegetation on roof. Remove vegetation if root system is damaging roof.
• Repair cracks in concrete if greater than 1/16".
• Repair spalled concrete.
• Remove rust from all metal elements. Abate or encapsulate lead-containing paint. Treat metal with rust inhibitor, and paint with approved historic colors. Repair damaged clay vent pipe.
• Extend searchlight tracks to historic position.
• Mount searchlight on narrow-gauge rails (after confirming that the existing searchlight within the structure is the correct type).
• Ascertain source of water in cable pit. Drain pit and arrest source of water if possible.
• Determine extent, type and location of wall lights and cabinetry. Replicate if possible using photographs, drawings and/or oral accounts.

SEARCHLIGHT SHELTER NO. 19: PRESERVATION

• Remove invasive vegetation.
• Repair spalled concrete.
• Repair cracks in concrete.
• Treat exposed reinforcing bar.
• Remove rust from all metal elements, abating lead paint hazard, treat with rust inhibitor, paint with approved historic colors.
• Consolidate or replace in-kind deteriorated wood curbs under roof.
• Realign metal roof.
• Paint with approved historic colors.

GENERATOR STATION FOR SEARCHLIGHT NO. 18 & NO. 19: RESTORATION

• Remove invasive vegetation.
• Photo document, measure and record interior furnishing ghosts prior to any interior painting.
• Repair spalled concrete.
• Remove peeling paint, abating lead paint hazard, treat any exposed metal, repaint with approved historic colors. Do not paint interior impact spalls, leave exposed to reveal holes.
• Remove rust from all metal elements. Abate or encapsulate lead-containing paint. Treat metal with rust inhibitor, and paint with approved historic colors.
• Repair partially missing interior wood door surround.
• Restore double hung and hopper windows: remove security bars, chicken wire and plywood infill, replace with glazing.
• Replicate missing exhaust vent in-kind.
• Replace missing metal covers from interior cable troughs.
• Restore doorway to original single door width: remove plywood infill, replicate original wood door.
• Remove infill from second original large window opening.
• Remove bird's nests from exterior vent holes. Cover with screens to prevent further nesting.
• Reconstruct conduit chases.

BASE-END STATION, BATTERY MCGRATH: PRESERVATION

• Remove invasive vegetation at entry hatch.
• Treat exposed reinforcing bar.
• Repair concrete spalls.
• Repair cracks in concrete.
• Remove rust from all metal elements, abating lead paint hazard, treat with rust inhibitor, paint with approved historic colors. For sharp protruding metal on hatch, bend metal back into position or file sharp edges.
• Monitor structure for signs of water infiltration. Reapply bituminous waterproofing to roof if necessary.
• Reattach shutter (currently located inside the structure).
• Remove non-historic graffiti.

BASE-END STATION, BATTERIES CALEF & WILKESON: PRESERVATION

• Remove vegetation from roof drainage channel.
• Repair cracks in concrete.
• Repair spalled concrete.
• Remove rust from all metal elements, including hardware and hatch cover. Abate lead paint hazard, treat with rust inhibitor, paint with approved historic colors.

BATTERY COMMANDER STATION, BATTERIES CALEF & WILKESON: PRESERVATION

• Remove invasive vegetation.
• Remove lichen growth, after first locating and eliminating water source. If hillside drainage is inadequate, create swales to carry water away from structure.
• Repair spalled concrete. Repair spalls surrounding ceiling conduit.
• Repair cracks in concrete.
• Monitor and assess cause of corrosion stains on concrete. (Removing stain is optional for ultimate treatment of preservation.)
• Remove rust from all metal elements, including hardware, abating lead paint hazard, treat with rust inhibitor, paint with approved historic colors.
• Clean efflorescence from north concrete wall after eliminating water source.

BASE-END STATION AT BILLY GOAT POINT: PRESERVATION

• Remove vegetation from roof.
• Remove interior debris.
• Repair concrete spalls, taking special care to repair concrete curb at entry hatch and the front shutter support.
• Repair cracks in concrete if greater than 1/16".
• Survey exposed reinforcing rod to determine if it warrants cutting out and replacement or treatment in place. Monitor reinforcing rods located near the surface of concrete that are causing surface spalls.
• Reinstall metal shutters and hardware.
• Repair or replace damaged shutter hardware in-kind.
• Remove rust from all metal elements, abating lead paint hazard, treat with rust inhibitor, paint with approved historic colors.
• Remove or paint over non-historic graffiti.

BATTERY COMMANDER STATION AND BASE-END STATION, BATTERY HUMPHREYS: RESTORATION

• Remove interior debris.
• Repair concrete erosion if more than 1-2" of surface concrete is missing or if reinforcing rod is exposed.
• Repair concrete spalls., especially at rear of upper roof and at hatch curb.
• Repair cracks in concrete.
• Survey exposed reinforcing rod to determine if it warrants cutting out and replacement or treatment in place.
• Remove rust from all metal elements. Abate or encapsulate lead-containing paint. Treat metal with rust inhibitor, and paint with approved historic colors.
• Replicate missing upper level room azimuth instrument pole.
• Re-attach missing azimuth instrument stand in lower level front rear (it is presently located on its side in the lower level rear room.
• Replicate and replace wooden swivel bench.

BASE-END STATIONS, BATTERIES WOODWARD & GRANT: RESTORATION

• Remove interior debris.
• Remove vegetation from roof drainage channels.
• Repair concrete spalls, especially where reinforcing rod is exposed. Where reinforcing rod is exposed, clean and coat rod or cut out and replace if required.
• Replace missing roof camouflage stones in-kind (approximately 15) using pins if necessary. Clean and fill roof cracks.
• Remove rust from all metal elements, abating lead paint hazard, treat with rust inhibitor, paint with approved historic colors.
• Remove non-historic graffiti from concrete walls, or paint over if surface was originally painted.
• Clean efflorescence from concrete wall after eliminating water source.
• Replicate and replace wooden swivel bench.
• Paint concrete with approved historic colors.

BATTERY COMMANDER AND BASE-END STATION, BATTERY ASHBURN: RESTORATION

Note: Painting occurred in early 1998, and was in progress during field work for this report. We do not know the extent of testing, cleaning and preparation that occurred prior to this work, nor do we know the authenticity of the selected colors. We suggest monitoring this structure for signs of recurring cracking, spalling and corrosion.

• Repair concrete spalls, with special attention to door header. Cut out and replace or treat existing reinforcing rod at this location as needed.
• Repair cracks in concrete.
• Replace metal pipe railing in-kind.
• Remove rust from all metal elements, abating or encapsulation lead paint. Treat with rust inhibitor, and paint with approved historic colors. Recent painting of metal shutters did not remove rust.
• Remove plywood infill at exterior door and replace metal vents at upper and lower openings.
• Replace strip fluorescent fixtures with historically appropriate incandescent (probably bare lightbulb and plain socket.
• Remove peeling paint from floors.
• Replicate and install missing camouflage netting. Netting to be attached to extant eyebolts at roof.
• Review roof slab drainage. Create swales to redirect any surface runoff.
• Remove efflorescence and conduct repairs at exterior door soffit.
• Restore function to metal shutters by removing wood and clamps. Repair or replace in-kind window shutter hardware.
• Straighten bent metal shutters at lower level.
• Replicate and replace removed chart shelf.
• Replicate and replace missing window shelf.
• Remove brick rubble from lower room.
• Reopen electrical raceways between lower rooms.
• Replicate missing metal door frame to match adjacent galvanized metal.

BATTERY BLUFF, NORTH AND SOUTH GUN EMPLACEMENTS: STABILIZATION

• Monitor subsidence of hillside below structures.
• Clear structures of soil and vegetation infill.
• Repair cracks in concrete.
• Perform photographic, written and graphic documentation while structures are still intact and before hillside instability renders vicinity unsafe. Follow the Secretary of the Interior's Standards for Architectural and Engineering Documentation, Historic American Building Survey/Historic American Engineering Record (HABS/HAER).
• Restrict access to area if advised to do so by soils engineer, and post erosion warning signs.

BATTERY POINT LOMA PANAMA GUN MOUNT: STABILIZATION

• Leave Panama mounts 1, 2, and 3, covered until their ultimate treatment designation is upgraded.
• Repair concrete spalls if larger than 4" x 4" x 1", or if reinforcing rod is exposed.
• Repair cracks in concrete if over 1/16" wide.
• Remove rust from all metal elements, abating lead paint hazard, treat with rust inhibitor, paint with approved historic colors.
• Reattach steel band at central concrete mount, replacing missing bolts.
• Analyze slope erosion and determine if measures are necessary to prevent future soil movement.

BATTERY POINT LOMA BUNKER COMPLEX, GUNS 1&2: STABILIZATION

BATTERY POINT LOMA BUNKER COMPLEX, GUNS 3&4: STABILIZATION

• Replace missing bolts and nuts from metal sections.
• Treat corroded galvanized steel with a rust converter (such as that made by Rustoleum).
• Provide photographic, written, and graphic documentation of structures following the Secretary of the Interior's Standards for Architectural and Engineering Documentation, Historic American Building Survey/Historic American Engineering Record (HABS/HAER).
• Excavate infilled bunkers.

BATTERY POINT LOMA RESERVE MAGAZINE

• Repair concrete curbs.
• Protect stenciled graffiti.
• Stabilize collapsed wood and chicken wire assemblies. Store material on-site in a locked location until ultimate treatment designation is upgraded and bunks can be reassembled.
• Replace missing bolts and nuts from metal sections.
• Treat corroded galvanized steel with a rust converter (such as that made by Rustoleum).
• Provide photographic, written, and graphic documentation of structures following the Secretary of the Interior's Standards for Architectural and Engineering Documentation, Historic American Building Survey/Historic American Engineering Record (HABS/HAER).