of the sidewall is before installing siding. Simply install insulating sheathing over existing siding, over or between the furring strips. Laying the groundwork: Determine a starting point for your siding -- it should be the lowest point. Measure at corners, and pull a chalk line across the wall to ensure a level starting position. Plumb corners, and shim if necessary, to ensure they are vertical. Preparing the Walls Important Notes: Weather Resistant Barrier Vinyl siding has always been designed as an exterior cladding, not a weather resistant barrier. Vinyl siding is designed to allow the material underneath it to breathe; therefore, it is not a watertight covering. Because of its design and application, it provides a supplemental rain screen that enhances the weather resistant barrier system by reducing the amount of water that reaches the underlying weather resistant barrier. Preparing the Walls A flat, level wall surface is necessary for proper installation of vinyl siding. Install flashing before starting to apply the siding. Unless already installed, a weather resistant barrier should be applied to the house prior to installing vinyl siding. Always consult local building code for requirements in your area. New Construction Tip: To reduce the possibility of the floor-plate compression, drywall, roofing, or other heavy building materials should be installed or stored throughout the house prior to the installation of vinyl siding. Floor-plate compression can result in buckled siding at the intersection of the floor and the wall. Residing Nail down loose boards of existing siding, and replace