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Bjorklund Hotel Stabilization Project
by Susan Turner and
Robin E. Whitehurst The Bjorklund Hotel is a historic masonry structure at the State Historic Site of Bishop Hill, Ill. Built by Swedish immigrants, followers of Erik Jansson fleeing religious persecution, it is part of a planned community of structures, some of which are still occupied by descendants of the original settlers.
The hotel is a three-story masonry structure faced in stucco, with timber floor and roof framing.
The building was in poor condition when it was acquired by the Illinois Historic Preservation Agency. Although IHPA had undertaken various projects at the building, such as rebuilding the cupola and repairing interior plaster, significant work was still needed. The exterior wall was displaying both horizontal and vertical cracking.
Bailey Edward Architecture of Chicago was retained to stabilize the building to be consistent with the Secretary of the Interior’s Standards for Rehabilitation.
Research
The first step was to investigate by taking soil borings. These determined that the soil was glacial loess, a low-strength, clay-like material that expands with moisture and contracts when dry. The next step was to excavate along the foundation to verify the existing footing of the foundation system and its condition.
Due to the historical significance of the building, all excavation of the first 18 inches of soil depth needed to be performed by an archaeologist. Floyd Mansberger of Fever River Research was retained, and five test pits were identified for investigation. The archaeological investigations revealed a drain tile made of brick, and the original root cellar wall installations. Historically, a root cellar was added by excavating beside a structure and laying the brick up against the earth excavation. The interior was then faced neatly in masonry.
Approached from the exterior through the excavation, the masonry was crude and sloppy. The severe deterioration required complete reconstruction of the outer wythe.
The test pits also revealed a masonry foundation with an average depth of 25 to 30 inches. The three wythes of brick had been locally made, and about 10 percent of the bricks were underfired. Between the poor soil and the shallow, narrow foundation, it was determined that new spread footings beneath the original walls were required.
Stabilizing the
masonry foundation
The solution to the differential settlement was to install 12-inch-thick by 4-foot-wide continuous footing under the perimeter foundation. The foundation was carefully exposed in sections. The footing excavation was undercarved in 3-foot sections six feet apart, with perpendicular support for the masonry. This would reduce the stress on the masonry from loss of support. A modified auger was used to drill from the exterior side since the interior wasn’t accessible. The earth was cut neatly and the reinforcement placed into the earth on either side. The process was repeated for the 3-foot sections to the left and right.
Although excavations were minimized as much as possible, a historic brick walk had to be removed to gain access to the foundation to do restoration work on the east side of the building. The historic surface pathway was removed, documented by the archaeologist with full-size templates, and the bricks numbered and labeled, permitting their exact reinstallation.
Once the foundation was stabilized, the masonry restoration work could begin.
Masonry
The subgrade brick was spalling and the mortar was dissolving. Full repointing of the below-grade masonry was required due to its degradation from settlement and moisture. Investigation of the mortar revealed it to be Type N, using a 1/1/6 mix of hydrated lime, portland cement and sand. The sand was well matched due to the contractor’s resourcefulness in finding a good small source near Galva, Ill. Natural iron oxide completed the recipe for matching the original mortar appearance.
The typical discussion on the use of power tools (or not) was not an issue on this project. The mortar was so deteriorated that it was more like sand, needing very little effort to be scraped out. Upon completion of the masonry work, the foundation wall was waterproofed, using a cold fluid-applied membrane, Carlisle CCW-525-V.
Part of this project included the reconstruction of the chimneys, which had deteriorated due to their exposed location. Where bricks were to be concealed in the foundation, new bricks were used. Where bricks in exposed locations such as in the chimney required replacement, they came from salvaged bricks or from the site’s limited stockpile of historic bricks.
Structure
Generally, the structure was not included in this work. There was one area where the joists did not manage to reach the foundation wall on which they were to be supported. At the time of construction, the tradesmen placed a brick ledge that didn’t sufficiently support the joists. New concrete block piers were added under the joists to support them. The choice of concrete block was justified by the area’s concealed location in a crawlspace and as a way to underscore the fact that these were new interventions, easily differentiated from the historic construction.
By working closely with the contractor, the team managed to find good solutions. Thanks to their efforts, the project received a special preservation award from the Illinois Capital Development Board’s Pride in Partnership Awards program.
Robin E. Whitehurst is a principal of Bailey
Edward Architecture, a firm specializing in
preservation and adaptive reuse. He can be
reached at robinw@bedesign.com.
Susan Turner is a Canadian architect practicing
with the firm of Bailey Edward Architecture.
She can be reached at sturner@bedesign.com.
Due to the historical significance of the building, all excavation of the first 18 inches of soil depth needed to be performed by an archaeologist. Floyd Mansberger of Fever River Research was retained, and five test pits were identified for investigation. The archaeological investigations revealed a drain tile made of brick, and the original root cellar wall installations. Historically, a root cellar was added by excavating beside a structure and laying the brick up against the earth excavation. The interior was then faced neatly in masonry.
Masonry
manage to reach the foundation wall on which they were to be supported. At the time of construction, the tradesmen placed a brick ledge that didn’t sufficiently support the joists. New concrete block piers were added under the joists to support them. The choice of concrete block was justified by the area’s concealed location in a crawlspace and as a way to underscore the fact that these were new interventions, easily differentiated from the historic construction.