What is the best type of building paper to use between sheathing and siding?

The best type of building paper to use between sheathing and siding is asphalt-saturated building paper. This type of paper is specifically designed to provide a moisture barrier while allowing for vapor transmission, which is crucial for the longevity and performance of the building envelope. Asphalt-saturated paper serves as an effective weather-resistive barrier that helps protect the sheathing from moisture infiltration, thereby reducing the risk of rot and mold. Its durability and resistance to water make it particularly suitable for various climatic conditions.

Other types of papers listed have different properties and applications. For example, vapor-resistant materials are primarily designed to control moisture movement but may not provide the same level of protection against wind and rain as asphalt-saturated paper. Machine-finished (waxed) paper might offer a slick surface but is not commonly used as a building paper in exterior applications due to potential issues with adhesion and effectiveness in moisture management. Non-par finned materials are typically used in other contexts and do not function effectively as a moisture barrier in the same way that asphalt-saturated paper does.

In summary, asphalt-saturated building paper strikes the right balance for its intended use between sheathing and siding, ensuring optimal protection against moisture while allowing necessary vapor flow.