Rosin paper

In building construction, rosin paper is used to reduce air and moisture flow through a wall or floor, create a "friction barrier" so different materials can slip by each other as they expand and contract, keep dust from working down through a floor, and minimize squeaking.

Rosin paper is also sometimes used to temporarily protect a work site during construction.

Papers from the Middle Ages were sized with gelatine, but the invention of the paper-making machine in the late 18th century demanded a better size [1] resulting in utilization of rosin.

Rosin paper may have a polyurethane coating to improve moisture resistance and tearing.

Alum-rosin size was invented by Moritz Friedrich Illig in Germany in 1807[2] and is known to have been used as a building paper by 1850.