If your wood siding has rot or water damage, applying vinyl siding over the wood siding will just compound the problem. Identify the source of the water damage and stop it. If the damage comes from outside sources, like rain or snow, be sure that the wood is dry before you proceed.
For external wood damage from rain or snow, install furring strips or foam board over the wood siding before you put up the vinyl siding. In fact, most homeowners install foam board before putting vinyl siding over wood siding because it evens out the surface, making installation easier.
Once you apply the foam board or furring strips, applying vinyl siding over wood siding is no different than any other vinyl installation. First, take measurements and carefully plan the layout of your siding.
Deciding how to apply vinyl siding depends on your home's levels and architecture. Measure your exterior and plan the installation following these rules: Match up the siding around corners, make sure that there isn't a narrow strip of vinyl siding under windows and doors, and install your vinyl so that it is level.
Know that cutting vinyl siding is easy. Use either tin snips or a circular saw with a fine-toothed blade to cut vertically. To make long horizontal cuts, score the siding with a utility knife, then bend the siding back and forth along the score line to snap it off.
Nail vinyl siding panels to the house using galvanized roofing nails large enough to reach into your wood studs at least ¾ inches. There will be designated nail slots in the vinyl siding. Vinyl siding expands and contracts with weather conditions, so it needs room to move. If you can't move a panel after you have nailed it in, it is too tight. Check the installation manual for your vinyl siding to see exactly how much space to leave between the nail and the siding.
Things You Will Need
- Foam board or furring strips
- Vinyl siding
- Tin snips (or circular saw with fine-toothed blade)
- Utility knife
- Galvanized roofing nails (long enough to penetrate 3/4-inch into wood studs)
- If you can't locate the source of severe water damage or correct the problem, you are better off removing the wood siding before you install vinyl siding. If your house has settled or it is uneven in spots, like under soffits, it is OK to install the vinyl so that it is parallel with the house instead of level. Your goal is to use complete vinyl panels on the most visible parts of the house. If your house changes levels, like a split-level, start with the most visible areas. Then as you move around the house and need to complete a section with a partial panel, you'll be in the less visible areas.