THE IN SITU TREATMENT OF THE WALLPAPER IN THE STUDY OF THE LONGFELLOW NATIONAL HISTORIC SITE
Thomas K. McClintock
The problems affecting the wallpaper had a number of sources. The underlying plaster was applied in several layers. It was subject to stress as it responded to the seasonal fluctuations of temperature and relative humidity, to the loads and vibrations of human occupancy and to the settling of the structure. Consequently, in many areas the plaster had separated from the wall and slipped away, leaving holes, with fragments lodged under the wallpaper. The most disturbed areas were at the top of each wall where the last layer of plaster abutted the bottom of the cornice and above the windows where the projecting curtain bars were subject to great loads. It was on this insecure base that the layers of wallpaper were laid.
The wallpaper itself was very brittle, with dried mounting adhesive on one side and two layers of paint on the other side, but it had in general accommodated the stressed imposed on it with remarkable flexibility. The shifting plaster caused the paper adhered to it to move as well, forming draws at the intersections of the walls and just below the cornice. There were areas where the plaster layers delaminated, leaving the outer layer of plaster to be supported in place by the wallpaper, and where the plaster cracked and fell away, leaving the paper with no base to which it could be readhered. A lesser problem was the simple loss of adhesion of the wallpaper to sound underlying plaster, detectable by lightly tapping the wallpaper. There were numerous tears and losses in the paper. Most occurred before the second painting in 1945: those areas of exposed plaster were covered with the same surface layer of brown-mauve paint as the wallpaper. There was variation in hue and intensity as some areas had been more protected from soiling and exposure to light. Some areas were missed in painting the second layer and the original darker brown is revealed here. The second layer of paint, an ordinary oil-base interior paint, was thickly applied and brush strokes were apparent. Both layers were well bonded to each other and to the paper support. There was little evidence of cleavage.
The house was heated by a coal furnace until 1974. As a result, wall surfaces were covered with a thick, dark coat of grime.