I remember volunteering at the Stansbury House in Chico, CA during my college days and being fascinated how cool the house felt during those hot summer days. Upon further investigation I learned that flat plaster walls are an integral part of both the historic and environmental value of older homes. Yet it seems that plaster is the first thing that contractors will tell you "has to go". Actually, more often than not, it will be removed because either the contractor doesn't have the proper knowledge necessary to make the proper repairs and/or the homeowner does not realize what will be lost along with its removal.
Homes built of wood and plaster are actually a superb, natural-functioning system. While humidity passes through the materials to the outdoors, heat and cold are not transferred. In fact, plaster and wood are very poor conductors. The chilly interior drafts that you feel each winter pouring through the joints, cracks, and crevices and are not coming through the walls themselves, but through other means such as crack in windows, etc. Also, well-intentioned improvements like blown-in insulation and vinyl siding actually defeat the old, efficient system of moisture exchange and add little to improve on the insulating air pocket between plaster lath and exterior walls. Worse yet, these materials greatly increase the chance for damaging moisture build-up and harmful mold growth, as well as trapping the toxic fumes from paint finishes and petroleum furnishings.
Although the environment concerns are significant, it is the rich, textural beauty of plaster that is the greatest asset and the most compelling reason to preserve and restore this valuable material. The alternative, modern drywall, has a flat cardboard-like appearance and lacks the sound-insulating quality and fire resistance of plaster. The transmission of voices, footsteps, music and plumbing sounds is particularly troubling. In addition, replacing plaster with standard drywall has the effect of reducing the historic integrity of the building and, therefore, impacts the monetary value of the home within the historic home market.
