Fullersburg Woods Graue Mill Structural Improvements Project

Located in the southern corner of Fullersburg Woods Forest Preserve, Graue Mill and Museum is one of the area’s remaining authenticated Underground Railroad “stations” and the only operating waterwheel grist mill in Illinois. Programs on milling, spinning and weaving illustrate life between 1850 and 1890 and the effect mills had on the area’s culture. The Forest Preserve District of DuPage County, in cooperation with the DuPage Graue Mill Corporation,  maintain and operates the Mill.

Frederick Graue, a German immigrant, settled in Fullersburg, Illinois, in 1842. In 1849, he purchased the site of a sawmill that had burned down, constructing a gristmill there that opened in 1852. Limestone for the basement walls was quarried near Lemont; bricks for the rest of the walls were made from clay from the Graue farm and fired in kilns near the mill site; flooring, beams and posts were from white oak timbers cut along the I & M Canal. The four one-ton buhrstones used for grinding were imported from France. The Graue Mill has been an integral part of the Oakbrook and DuPage County community for more than 163 years, first as an economic engine and currently as a historical landmark.

Graue Mill was listed in the National Register of Historic Places in May 1975 and in 1981 was recognized as an Illinois Historic Mechanical Engineering Landmark by the American Society of Mechanical Engineers -- the only gristmill so designated on a national or local level, representative of an important technology and era in the history of America.

However, March 2013 inspections of the mill found several areas of concern with the operation of the gear works, basement subfloor, and mill race foundation. Then in April 2013 a significant flood event left 5’ of water in the basement, contributing to further deterioration of the areas of concern. Engineering Resource Associates, Inc. (ERA) was hired in May 2013 to perform a structural conditions analysis as well as accessibility review of Graue Mill.   

The first part of their contract involved performing a preliminary evaluation to determine if it was safe to operate the millstones and the gear system based upon the noted concerns. In June 2013, it was determined to be unsafe to operate the millstones and gear system due to lack of support and stability to the load-bearing components of the jib crane for the millstones and mechanical gears. As a result, the grinding and gear works assembly had not been in operation since late June 2013.

After completion of the entire report, ERA found that in general, the Graue Mill is in good condition for a building of its age; however, there were critical deficiencies in the structural support columns and beams that needed to be fixed in order to ensure the long-term stability of the structure. While the interior and exterior masonry is in decent shape, tuckpointing and replacement of stones was necessary in locations where flooding has caused a rapid deterioration of walls and floors. There was also inadequate support and stability for the gear systems and the millstone crane operations. Lastly, there were significant ingress and egress issues as far as accessibility and safety for all visitors.

ERA recommended various structural repairs to address all of the concerns mentioned above. The estimated cost for these repairs was approximately $1.1 million. The District decided to perform the repairs in two phases, with the first phase focusing on critical structural repairs to better protect the building from flood damage while stabilizing the foundation.

Phase I Improvements include excavation on the east and west side of the mill to protect the foundation by adding a 8-inch thick concrete liner to the limestone foundation walls along with a damp proof coating below visible grade. In addition, the millrace masonry adjacent to the Mill’s foundation was tuckpointed to repair cracks and leaks. The remainder of the foundation was also tuckpointed and loose stones were reset. The northern-most portion of the basement floor of the mill was removed and the subbase was reinforced and filled with flowable fill before being replaced with a new concrete floor. During these floor repairs, drainage tile and a sump pit were added to help keep water from penetrating the basement. New foundations were poured to support the gear works and jib crane assemblies, and the main electrical service feeding the building and service panels were relocated from the basement. The work also included restoring the steel supports of the water wheel and removing and replacing rotted wood timbers in the millrace. Accessibility improvements were also made to the stairwells. To accomplish some of this work, the gear works assemblies and motors were removed and stored until they could be reinstalled. Repairs were also made to the jib crane on the first floor and the support beams under the jib crane in the basement, which enabled Graue Mill to use the millstones again to grind cornmeal. 

Phase II Improvements to be funded at a later date include restoration of the gear assemblies and motors, restoring and repairing altered wooden beams throughout the upper floors, tuckpointing the remainder of the millrace walls and additional floodproofing of the back of the millrace walls, HVAC and fire suppression modifications, and adding insulation in the attic.

Approximately $600,000 was budgeted in yearly appropriated Capital Development and District Wide Contingency Funds for Phase I improvements, which covered the structural analysis report, design, permitting and construction costs for Phase I Structural Improvements. Funding for Phase II Improvements will be considered in a future fiscal year budget.  

In June 2015 the Illinois Historic Preservation Agency (IHPA) approved the existing conditions and analysis report and proposed construction methods for structural repairs. The District obtained the building and stormwater permits for the improvements in spring 2016. Construction on the project began in spring 2016 and was completed at the end of summer 2016. The schedule for Phase II Improvements will be determined when funding becomes available.

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