in building construction red rosin paper is used to reduce air and moisture flow through a wall or floor, create a "slip sheet" so different materials can slip by each other as they expand and contract, keep dust from working down through a floor, minimize squeaking, and sometimes as part of built-up roofs. rosin paper is also temporarily used to protect a work site during construction. rosin paper may have a polyurethane coating to improve moisture resistance and tearing. it is not acid free particularly containing abietic acid and comes in many size rolls up to wide.