Vinyl siding can be installed directly over wall sheathing, wood siding or stucco. By doing so, however, you miss out on the opportunity to add add energy savings to the project.
Removing the existing siding offers the opportunity to install fiberglass, cellulose, or foam insulation into the wall cavity.
House wrap is a common type of insulation on new homes. The material is designed to keep out moisture and reduce drafts while simultaneously allowing the walls to breath. The wrap comes in rolls and is stapled directly onto the wall sheathing.
Fan fold comes in foam sheets and is nailed directly to the sheathing. While fan fold has minimal insulation value, it does even out wall defects and cuts down on drafts.
Furring strips may be necessary if you are installing vinyl siding over existing wood siding or stucco.
Before installing vinyl siding over existing wood siding or wall sheathing, the wood must be dry and in good condition. Installing insulation over moisture or existing rot can create larger headaches later.