Exterior Envelope and HVAC Systems

General Description: Building 3126, is located at 6988 Britten Road, Fort Belvoir, VA 22060. The building is an aircraft hangar with associated offices and work rooms. The hangar houses Research & Technology Integration's (Night Vision) Aircraft Component Maintenance Shop. The hanger was built in 1960, is a one-story building and has an area of 18,339 square feet. Existing conditions: B3126 is an aging building and suffers from deferred maintenance. The hangar bay is sided with corrugated sheet metal with a standing seam, sheet metal roof. One-story offices and work rooms are located to the northeast and southwest of the hangar bay. The northeast offices extend the full length of the hangar, while the southwest offices extend approximately 50% of the length of the hangar. The remainder of the southwest side has a wood lean-to shed and a small yard with grass. The one-story portions of the building have concrete masonry unit (CMU) walls and flat/minimally sloped roofs with a bituminous, built-up finishes. Floors throughout the building are concrete. The floor in the hangar is painted. Office spaces have vinyl tile flooring, and some work rooms have painted concrete floors. The upper roof above the hangar bay appears to be in good condition but does not appear to have gutters and downspouts to appropriately handle runoff to the lower roof. Runoff drops approximately 10 feet to the surface of the lower roofs. The lower, minimally sloped roofs over the office and workspaces were replaced in September 2024 and included foam panel insulation. Portions of the lower roof decking over the mechanical room are failing. Existing windows, hanger doors and pedestrian doors appear to be contemporary with the construction of the building in 1960 and are now 63 years old. The windows are metal-framed, awning windows and uninsulated. Each window consists of 3 horizontal panes with the upper two (2) panes comprising the operable awing sash. Some windows have been replaced with fixed windows. Other windows or portions of window have been removed to allow installation of window mounted air conditioners and ventilation fans. Where window units and fans are installed, plywood or sheet metal has also been installed to fill in the remainder of the opening. Some windows have expanded metal grating installed on the interior side of the opening. Windows are inefficient, do not provide adequate ventilation for the activities in the building and do not meet current safety requirements. The pedestrian doors are hollow metal doors in metal frames and are uninsulated. The hanger bay doors are corrugated steel on metal frames. Each door opening has six rolling leaves that are installed on parallel tracks. Three (3) leaves for each door opening are stored in pockets at the left and right sides of each door opening. Subsequent repairs have added insulation and a sheet-metal, interior finish attached with machine screws that are proud of the finished surface. Opening the hanger bay doors causes the machine screws to impede the opening and scape against the other leaves of the doors. To facilitate opening the door a groove has been cut into the exterior face of the corrugated metal of other door leaves compromising the exterior envelope of the doors. The corrugated metal and CMU walls are in good condition with some areas of paint loss. The hangar bay walls, and roof have been insulated. Hangar bay insulation has been damaged by wildlife intrusions into the building from the adjacent wooded areas surrounding the airfield and water infiltration at the grade beam foundation of the hangar. The upper portion of the interior side of the exterior CMU walls of the offices and work rooms have been furred out and insulated above the radiator units attached to the CMU walls that provide heat for those spaces. The space between the floor and bottom of the furred-out portion of the wall is uninsulated. Heating and cooling of the hangar is by overhead-mounted, gas-fired, infrared, space heaters and wall mounted fans which are to remain. The offices, work areas and mechanical room are heated by wall baseboard radiators and unit heaters and cooled by window mounted air conditioners. The heating water was provided by the condensing boiler with BAS controls in the mechanical room which is not functioning correctly and does not supply hot water to the baseboard radiators. Water infiltration occurs near the south corner of the hangar and at the threshold of the northeast elevation pedestrian door to the offices. The work area shall include the interior and exterior sides of the exterior walls and the interior side of the roofs. Work area shall include the finished surfaces and furr-outs of the walls, floor and ceiling but not the framing or structure of the walls of the work area unless otherwise noted. Wiring, conduit, piping and other utilities inside the walls and serving the work area shall also be included in the work area. Interior ceilings in the office and work areas are the underside of the roof decking above with exposed steel beams (approximately 8-9 to 9-0 to bottom of beam). The hangar houses two aircraft. Coordinate all work in the hangar with the tenants. The laydown area shall be coordinated with and approved by the tenants prior to the start of work. The hanger will remain occupied and operational during construction. A phasing plan shall be required. The phasing plan shall be submitted for review and acceptance by the Davidson Airfield Safety officer, DPW Engineering, and the tenants. The building is on an active airfield. The contractor shall coordinate access and work with the building's FACO, building's security, and airfield management.