Salvage Process in Pictures: West Experiment Station
The University of Massachusetts Amherst Physical Sciences Building (PSB) project includes the recreation of West Experiment Station (WES), a 19th Century research laboratory and one of the University’s oldest buildings. Unfortunately, the WES is structurally unsound, due to weak mortar in the building’s structural bearing walls. To save the building, the project dismantles the WES, salvages its exterior red brick, and re-creates the building’s 1880s appearance atop a new fireproof steel skeleton. The “new WES” will house faculty and graduate student offices for the Physics department.
Wilson Architects engaged a team of masonry restoration experts to conduct in-depth structural evaluation of the West Experiment Station. Building Envelope Technologies (BET) led the effort, with expert assistance from Structures North, RJ Kenney, Atlantic Restoration, and Highbridge Laboratories. WES masonry evaluation included detailed visual examination, infrared imaging, hammer testing, cores through the exterior walls, ‘flat jack’ testing, and laboratory brick and mortar analysis.
Visual and infrared survey of exterior brick walls, by Building Envelope Technologies. A visual review identified isolated areas of mortar deterioration and loose bricks consistent with structures of similar age and construction technique. Surprisingly, thermal imaging showed significant voids within the masonry bearing walls, including abandoned chimney flues.
Masonry Survey – East Elevation, by Building Envelope Technologies and Structures North. Hammer sounding, combined with visual and IR survey information, produced detailed maps of the exterior walls. The maps showed that 1/3 of the total brick area was loose and/or hollow.
Core drilling process, by Building Envelope Technologies with Atlantic Restoration. Core samples as best reconstructed by BET. Core sampling resulted in immediate shear failure of the mortar. Samples fell apart and could not be evaluated for strength. This result indicated significant structural weakness throughout the entire structure, which could not be remediated with repointing.
‘Flat Jack’ testing location. ‘Flat jack’ testing exerted mechanical forces into the brick walls through slot cuts in the mortar bed joints. Multiple test cuts were made to determine the compressive strength of the masonry bearing walls. Results indicated minimal strength.
Brick and mortar samples examined by Highbridge Laboratories. Laboratory testing of brick and mortar materials indicated minor variations in the brick and mortar characteristics of the original 1887 structure vs. the 1890s addition. Bricks used in 1887 were hard and uniform (good quality), while the 1890s brick suffered from high water absorption. Lime-based mortar used throughout the building was significantly oversanded, resulting in weak compressive strength and poor bonding to the brick.
C 1895 photograph of the West Experiment Station, showing porte cochere and original rear ells. UMass Amherst Special Collections. The combination of poor strength throughout all the masonry walls, coupled with the high absorption of the 1890s addition bricks, led the team to propose the concept of salvaging the exterior masonry and rebuilding the original 1880s appearance of the WES.
Wilson Architects studied existing architectural details, such as the brick chimney pictured. Architectural drawings explored how to properly detail reused elements in the rebuilt scenario. The team explored key concerns, such as using proper masonry anchors, upgrading the design to current seismic codes, and incorporating modern insulation materials and methods, to ensure compliance with the energy code. All of these factors were balanced against a faithful recreation of the building’s original exterior appearance.
Wilson Architects re-construction drawing – South Facade, illustrating exterior and interior salvage elements. A system for cataloging and tracking individual salvage elements was incorporated, to facilitate removal, cleaning, repair, storage, and eventual recreation.
Salvage drawings included detailed illustrations of interior elements, such as the bank vault and fireplace. Photographs were incorporated to clarify key elements of salvage activity.
Progress Aerial photo showing the WES prior to masonry wall salvage. Construction began with site clearing, asbestos abatement, millwork salvage, masonry cleaning, and roof and chimney removal.
Wilson Architects, in consultation with Heritage Planning and Design, selected masonry cleaning agents to remove dirt and carbon buildup from the 120 year old bricks, without damaging the original appearance (“preserving the patina”).
Careful interior demolition removed deteriorated interior equipment, finishes, trim, plaster, etc. while working around large pieces of casework which were being salvaged. Demolition revealed interior brickwork which had been buried within the walls since the 1890s addition. It was determined that this brickwork would be salvageable for use in the recreation. These bricks could be used to replace any damaged or deteriorated brickwork from the exterior walls.
Salvaged millwork items, including original wood cabinets and casework were individually crated and carefully removed from the WES. Large cabinets were removed by crane through the skylight opening to avoid having to chop the cabinets into smaller pieces to get them through the doors. Photo courtesy Bruce Austin, DCAMM.
Champlain Masonry used photography to create detailed maps of the WES exterior walls. Each masonry element bears a numerical key code to identify it for reconstruction by a future mason.
Shoring and bracing was installed within the building to stabilize the structure during the salvage process. The West, South, and East (original 1880s) facades were fully scaffolded to allow masons to carefully remove the brick course by course.
As salvage progressed, Champlain Masonry stacked different types of bricks on pallets, with their “outward facing” sides up. Window arches were kept together with their brownstone elements, and placed into individual, labeled boxes.
Unique masonry elements, such as the detail brickwork from the original chimneys, were stored in custom-made boxes and labeled with their unique identification codes.
Aerial Photo showing the West Experiment Station site, with “un-bricking” substantially complete (left side) and cleaning / packing activity underway (right side). “Un-bricking” of the exterior walls was only the first step in a long process of cleaning, creating custom boxes, carefully packing, labeling, storing, and eventual rebuilding.