sound-proofing qualities when used with lime or gypsum plaster, which is denser than modern drywall. In many historic buildings lath and plaster ceilings play a major role for the prevention of fire spread. They are critical to the protection of horizontal elements such as timber joisted floors, including the flooring on top, which in terms of fire performance is often in a poor condition due to the presence of gaps. See also Laths Stucco References External links Plaster Base Installation, Building Construction & Finishing Preservation Brief No. 21 by the National Park Service. Contains detailed descriptions of Lath & Plaster construction and advisories on repairing and restoring these walls (especially in historic buildings). Building engineering Building Plastering