Workers from the Historic Preservation Training Center install replacement slates on the rear ell of the Thomas House.

The Thomas House is a two-story brick manor house constructed ca. 1780 by James Marshall. The house and its surrounding 240-acre farm was purchased in 1860 by C. K. Thomas, a retired merchant. The house sustained major damage during the Battle of Monocacy, and remained in the Thomas family until the early 20th century.

The National Park Service acquired the Thomas Farm in 2001. Soon after acquisition of the house, it became apparent that the slate roof covering had reached the end of its lifecycle and needed to be replaced. It was also clear that the three dormer windows needed significant repair and rehabilitation in order to preserve them and to ensure their continued function. The slate roof replacement and dormer window project began in fall 2006, and was completed in spring 2007. 

Epoxy repairs are performed on one of the dormer windows. Deteriorated elements are repaired when possible, or replaced in-kind.

As a result of years of exposure to the elements, the Thomas House dormer windows had begun to fail, allowing damaging moisture to infiltrate the building. During its years in private ownership, numerous repairs and alterations had been undertaken, sometimes with detrimental results. Significant repair and rehabilitation was required to return the windows to an operational condition. 

The dormers feature delicate dentils, rope moulding, and other details which had become obscured by years of repainting. A component of the dormer window project was a restoration and repair of these delicate decorative features, including removal of years of hazardous lead paint. The project restored the dormer windows to a fully functional condition, and also preserved these important historic details.

The Thomas House slate roof replacement project and dormer restoration was performed by the National Park Service's Historic Preservation Training Center (HPTC). HPTC is headquartered at Monocacy National Battlefield in the historic Gambrill House.

To see photos of the Thomas House Slate Roof Replacement and Dormer Window Repair and Rehabilitation project, click on the links below.