ARLINGTON HOUSE Historic Structures Report Supplementary Material

Strengthening of the floor system above the north arch in the upstairs center hall and of the main stairway was accomplished in early 1978 under the direction of Mr. Longworth.

The floor system above the north arch of the Centerhall depended on the seating of the joists in the brickwork of the top of the arch. The brick, unusually soft and deteriorated due to initial underfiring when made, had crushed and no longer supported with any solidity the joists above. After removal of flooring in the area between the pilasters separating the upstairs servants' stair hall from the center hall section, joists above the arch were cut back to allow the insertion of a header seated on metal plates on the bases of the opposing pilasters on their south face. The joists were attached to this header and secured by Teco clips. With all joist load taken off the deteriorating arch, the floor became more stable and the structural defeciency was corrected.

A similar condition to the one just described existed across the hallway over the south arch. The situation over the south arch was complicated, however, by the presence of the main stairway as well as the stairway to the attic, both of which landed on the second floor just over the arch. Again, flooring was removed, the floor joists cut back, a header was seated on metal plates on the bases of the opposing pilasters on their north side. The joists were attached to this header and secured with Teco clips, thereby relieving the arch below and given the floor greater solidity.

Several further problems plagued the framing at the head of the main stairs in the Upstairs Centerhall. Once the flooring was removed it was found that there was no positive connection between the main stair stringers and the header which had been put in place between the bases of the pilasters on their south side when the house was constructed to catch the stair stringers. This header was doubled and the stringer both from the main stair arriving from below and those of the adjacent stairs departing for the attic were positively attached to the doubled header by metal straps fashioned for this purpose. Also the base of the newel post was solidly fixed to the header.

Work was also undertaken to strengthen the landing of the main stair. The header spanning the width of the stairway framed into the doorway between the South Stairhall and the White Parlor and into the area just beside the South Stairhall window. The framing system of the landing was weak due to the deep mortises cut into existing headers to catch the floor joists, thereby decreasing the effective sections of the headers. A double laminated header was added just above the doorway, and an additional timber along the side of the landing in front of the window. The existing header catching the stringers of both stairways was then attached to the new timbers with Teco clips. The connection between the header and the stair stringers was strengthened by the addition of metal connectors.

During the same year work was carried out in the basement at Arlington House in order to temporarily strengthen several weak points in the first floor framing system. Three beams with two posts each were placed under the North Stair Hall where the system had been damaged by beetles, the cutting of joists for a former stairway and for a diffuser of the heating system. Similar beams and posts were added beneath the heat diffuser duct opening under the South Stair Hall and to strengthen the lintel under the north arch between the Centerhall and the North Stair Hall. Posts alone were added at a weak point (one post) near the former stair opening in the Winter Kitchen, to stabilize the opening in joists around the stairway beneath the Pantry (two posts), and the beam under the southern half of the White Parlor (one post).

Harry Lee Arnest, "Arlington House, Historic Structure Report, Architectural Data Section (Phase I)," National Park Service, National Capital Team, Denver Service Center, September 1979, pp. 36-37.