New siding can be installed over existing exterior coverings in some cases. For homes with stucco exteriors, a framework of wood furring strips must first be installed to create a level surface, which suspends the outer layer of siding over the inner layer so that water cannot settle between the two and cause rot and erosion. Once the framework is laid, your new siding can be installed in relatively normal fashion. The process of installing siding over stucco walls requires an array of do-it-yourself skills and some basic tools.
Things You'll Need
2- by 3-inch furring strips
Circular saw with fine blade
Metal siding starter strip
Siding corner posts
Vinyl siding strips
Mark furring strip mounting locations across the length of your exterior stucco wall with a tape measure. Extend the tape measure across the base of the wall, using your marker to indicate a location every 16 inches. Because your stuccoed exterior wall has plywood sheathing beneath, it will not be necessary to locate studs in which to anchor your furring strips.
Stand a strip of 2- by 3-inch lumber at each mark, and use your level to make sure they are perfectly plumb. Use your nail gun and roofing nails to fasten each furring strip to the wall from the bottom to the top. The 16-inch spacing keeps the number of furring strips you will need to install down to a manageable number while providing ample support for your siding.
Cut and fit 2- by 3-inch furring strips around every window and door opening and each edge of every corner of the building as well. Install J-channel to the furring strips around each window frame. Use your tape measure to record the length of each edge of the window frame. Use your circular saw with fine blade to cut strips of J-channel to fit the perimeter of the frame, then use your snips to cut a 45-degree angle at the end of each strip of J-channel.
Fasten the channel to the furring strips using your hammer and roofing nails. Drive one nail into the fastener slot in your J-channel so that it has room to move to both the left and the right as the siding expands and contracts with the weather. Allow for a bit of space between the head of the nail and the channel. Use this technique when installing any channel or siding strips to the structure.
Locate the lowest part of the exterior wall and place your first starter strip 4 inches above the ground. Stretch a chalk line across the wall starting at the low corner. Use your level to make sure it is straight before snapping a guideline. Use your hammer and nails to fasten the starter strip to the furring strips already on your wall.
Install siding corner posts onto the furring strips on both edges of each wall corner. The posts should fall about 1/4 inch short at both ends to allow for expansion. The posts will overlap the ends of your siding strips and conceal any ugly details. Use your hammer and roofing nails to fasten them in place.
Place a level guideline every 4 inches above the bottom starter strip using your tape measure and chalk line. Use your hammer and roofing nails to fasten strips of siding to the furring strips. Offset each new piece of siding by 4 inches to create a staggered appearance. The bottom edge of each new piece of siding should lock into and cover the top edge of the last.
Notch the top edge of your siding strips with your razor knife. This will allow them to fit into the J-channel at the base of the window frame. Cut the siding to fit around the sides of the window and door openings and drive nails into the furring strips to hold them in place right around the edge of the frame. At the top of the window and door frames, attach the siding strip to a strip from the next row up. Install the two together for extra strength.
Do not put a bottom strip of wood as a mounting plate. Water can become trapped between the wood and the siding and then make its way into the home. Consider installing a wire mesh to keep out insects and small animals instead.
One benefit of installing new siding over old is that the insulation inside the walls remains intact. This means a second outer layer of protection is being placed over the first, and your home will be further protected against the elements.
Use a zip tool to feed the lip of one piece of siding over the last. This simple tool lifts and positions the siding strip so it fits tightly and easily in place.
Leave about 3/4 of an inch of room at each end of your siding strips. The gap will be covered by the corner posts and will allow for expansion.
Use caution when working with dangerous tools like saws, hammers and nails. Serious injury can occur. Wear work gloves and eye goggles for safety.