Despite the fact that it looks like a complex material to work with, vinyl siding is actually the easiest type of siding for a homeowner to repair or replace. Knowing the interlocking panel system is vitally important, but once you know the system, the only special tool that is needed is an unlocking tool (or zip tool), though if you intend to cover a new area, you will also need a snap-lock punch. Vinyl siding is designed to expand and contract with temperature changes, and to avoid any problems with the siding panels, there are a couple of simple rules that always need to be followed. First, always work from the bottom upwards when doing an installation. Each piece is designed to lock into the piece below it, before it is nailed into place. Second, when nailing a piece into place, leave 1/16-in. to 1/8-in. of the nail’s shank exposed, so that the panel can expand and contract without being damaged. If you are removing old vinyl siding which you intend to re-use, take care: old vinyl can be very brittle, and can be damaged easily.
Building Window Flashing
For a homeowner wishing to add a new window to a wall with vinyl siding, there are several very important steps that need to be followed in order to guarantee a professional-looking, and, crucially, a watertight job. Assuming the window has been installed, the next step is to make and install the aluminum flashing around the window. Following the bottom-up rule, the first piece to be installed is under the window. The width of this piece will vary, as it must both slide under the window’s nailing fin, while also overlapping the nailing hem of the piece of vinyl siding beneath the window. In terms of length, the piece should extend beyond the edge of the window so that the side flashing can overlap it. The flashing on each side is the next installation step. A 5-in. wide piece of flashing should slide beneath the window’s side nailing fin, and it should be long enough to overlap the bottom piece of flashing by 2 in., while extending above the top of the window by 2 in. as well. The final piece of flashing to be installed is the top piece. Like the sides, it should be 5-in. wide, and extend beyond the edges of the window to overlap both side pieces. Carefully, a slit should be made in the building paper, 2 in. above the window, and the piece of flashing should be slid behind it. The flashing should overlap the side flashing, and should also overlap the window’s top nailing fin. Roofing nails should be used to secure the corners of each piece of flashing.
After the flashing is installed, the next step is to install vinyl J-channels around the window. These divert water from around the window and cover the ends of the siding along the edge of the window. Again, work from the bottom of the window to the top. First, you’ll want to cut a piece of J-channel 2 in. longer than the width of the window, and use a utility knife to score a line 1 in. from each end of the piece. You will then want to use snips to cut to that score line, and remove the pieces. Position the piece underneath the window and using roofing nails positioned every 8-10 in., nail it into the nail slots, but not too tightly– you want the piece to move side-to-side slightly, in case you need to make adjustments. The side channels should have a 45-degree miter cut made to the ends, to lend a professional look to the installation. The top piece should overlap the two side J-channels, and like the flashing, should extend 2 in. beyond each edge of the window. However, unlike the bottom and side pieces of J-channel, which had 1 in. pieces removed from each end, the top piece should not have those pieces removed. Instead, the piece should be bent downwards and slid into each of the side J-channels to help divert any water away.
After installing the flashing and J-channels, the next step is to install siding around the window. As above, installation moves from bottom to top. First, measure the piece of siding to be placed below the window, and mark it ¼ in. to each side of the window to allow for expansion and contraction, and then measure it from the bottom of the undersill trim to the locking tab of the siding to determine the depth of the cut to be made. For the pieces of siding to each side of the window, feed the ends of the siding down the side of the channel that runs along the window, and into position. Finally, after positioning the side pieces and locking them into place, you will want to position the top piece, measure and make any necessary notches or cuts, nail it into place, and lock the piece into the pieces below it. A word of warning, however: vinyl siding will fade as it weathers and ages. To ensure the wall is a uniform color, it may be necessary to replace the entire wall, rather than use a mixture of new and old siding.