Before you put up your new siding, install Dow insulated sheathing right over your old siding and it will go a long way to help you save energy for years. And it makes your home more comfortable. It covers cracks in the walls and gaps around doors and windows. This helps prevent cold air from penetrating your home in the winter and hot, humid air in the summer. What's important too is that the rigid panels give you a smooth, level surface for mounting your new siding. The sheathing is easily installed over existing siding, then new siding, either vinyl, aluminum, fiber-cement, steel or wood is installed according to the manufacturer's recommendations.

Dow insulated sheathing creates the beneficial effect of a warmer wall stud cavity under winter heating conditions, reducing the potential for condensation within the stud cavity. However, where there is evidence of existing moisture related wall problems, corrective actions should be taken before proceeding with new siding application. Corrective actions may include:

1. Replacement or repair of rotted siding and trim
2. Increased attic ventilation capability
3. Installation of an interior – side vapor retarder

Since each type of siding may require specific application details, consult siding manufacturer's instructions before beginning project. Existing old siding should be in reasonably good condition before residing is started; loose siding should be secured, and all rotted siding, trim, sills, corner-posts, etc. should be repaired or replaced. Remove all gutters, downspouts, shutters, molding and old caulking around windows and doors.

Installation Instructions:

1. Secure insulation over existing siding with 3/8" (9.5mm) diameter head galvanized roofing nails with a minimum 3/4" (19.1mm) penetration or 1" (25.4mm) crown 16 gage staples with a minimum of 1/2" (12.7mm) penetration into a nail holding substrate. Suggested fastener spacing is a minimum 24" oc along each stud. Jamb, frame or sill extenders may be required depending on thickness of insulated sheathing used as well as siding manufacturer's application instructions. Suggest installing 4' x 8' insulation sheets vertically and 2' x 8' insulation sheets horizontally.

2. The new siding is applied in accordance with the manufacturer's instructions. Make sure that mechanical fasteners are long enough to penetrate both the Dow insulated sheathing and the normal securing substrate to a depth recommended by the siding manufacturer.

Use a utility knife and straight edge to trim the insulation board to conform to irregular wall angles, projections or wall surfaces less than board width or height.