Working with vinyl siding
Don't let the fact that you have vinyl siding deter you from that repair or remodeling project. If you want to shift a window, replace a door or even put on an addition, you can remove, alter and reinstall vinyl siding much more easily than any other type of siding. In this article, we're going to demonstrate how to rework the siding around a new set of windows.
We'll show you how to remove it, install new parts and then cut it, fit it and nail it back up. Most important, we'll show you how to make the installation watertight.
While we'll cover the basics, we won't cover every detail you might run into with your own project. Most manufacturers offer complete instructions; ask for them wherever vinyl siding is sold.
Working with vinyl doesn't require special skills, but you do have to understand the system. The only special tool you'll need for reworking areas is an unlocking tool, often called a zip tool.. (You'll need a snap-lock punch if you intend to cover new areas.) You'll probably need new trim pieces. We bought two types—J-channel to go around the new, larger windows (Photo 9), and undersill trim (see “When to Install Undersill Trim.”).You may also need additional siding.
Cutting Vinyl Siding
Vinyl siding is designed to hang loosely on the sheathing so that it can expand and contract with temperature changes. To prevent the relatively thin panels from buckling, observe these fitting and nailing rules.
- Leave a 1/4-in. gap at all ends. The siding slides behind trim pieces that hide the gap and the cut end.
- Lock the panel into the one below it, then gently snug it up before nailing. Marking the position of each piece before you remove it (Photo 2) will help you reposition the siding without stretching it.
- Center the nails in the nailing slots and drive them, leaving 1/16 in. to 1/8 in. of the shank exposed (Photo 14). The vinyl must be free to expand and contract.
Remove the siding
Photo 1: Unlock siding using a zip tool
Slide the zip tool under the butt edge of the siding, hook the locking edge and pull down. Then slide the tool horizontally along the lock to release it. Lift the unlocked siding to expose the nailing hem of the siding piece below. Draw a line on the wall along the top of each siding course before you pull the nails.
The beauty of vinyl is that you can remove a piece anywhere on the wall. Locate the piece you want to remove and unlock the one above it with the zip tool (Photo 1 inset). It might be tricky hooking the zip tool onto the locking edge if your siding is tight. Try starting at an end or look for a loose spot. Sometimes you can unzip it just with your fingers. If you're having difficulty with a particular lock, try moving up a course. New vinyl siding is quite flexible, especially in warm weather, but older siding becomes more brittle with age, so work carefully.
It should be easy to slide a flat bar behind the nailheads since they're not driven tight (Photo 2).Don't slide the flat bar behind the siding itself. You'll risk breaking it. You may have to bow each length of vinyl to release its ends from the trim moldings, and you may have to slide short pieces up or down past the window to release them from the J-channel.
Building paper and window flashing
Building paper is an important part of the wall's waterproofing. It's a barrier to any water that may work its way behind the siding, so be sure upper pieces lap over lower ones. Tape any tears or holes with housewrap tape (available at home centers).
Flashing is critical for a watertight window or door. Aluminum works best with vinyl. Buy a 10-in.wide roll of aluminum (at home centers), and cut it into 5-in.wide strips for the top and sides of the window. The width of the bottom flashing will vary. It must go under the window nailing fin and lap over the nailing hem of the vinyl siding (Photo 3). This will direct water to the front of the siding.
When you're done flashing the window, stand back and imagine water running down the wall. Start above the window and visually check that all building papers and flashing lap over the piece below it so water can't run behind.
Install J-channel around the window
Photo 8: Install J-channel under the window
Position the J-channel under the window. Cut and position an undersill trim if necessary (see "When to Use Undersill Trim."). Drive roofing nails every 8 to 10 in. through the middle of the slots. Don't drive them tight. The trim pieces should slide back and forth slightly.
Photo 9: Cut J-channel for the sides of the window.
Cut the side J-channel 2 in. longer than the height of the window. Make the miter cut on the bottom with shears. Cut a 1-in. notch on the top end as you did on the bottom J-channel. Lap the side over the bottom as shown. Drive roofing nails every 8 to 10 in. to secure it.
You have to wrap the window with vinyl J-channel to divert water and to cover the ends of the siding (Photo 9).You'll probably have to buy new strips for this. Start with the bottom piece and work up to the top (Photos 6 – 10). Make sure the pieces overlap to keep out water.
Mitered corners give a clean and finished appearance. Be extra careful to fit the top channel correctly over the side pieces (Photo 10) because a lot of water can run over these joints.
When to Use Undersill Trim
Because the siding is beveled, the cut edge under a window may end up about 1/2 in. out from the wall. If it falls 1/4 in. or less away, add the undersill trim to lock it in place (shown). If it falls more than 1/4 in. away, skip the undersill trim and simply rely on the J-channel.
If you're working over foam sheathing, place a piece of plywood between the foam and flat bar to avoid crushing the foam.
Install the siding
Photo 11: Mark the cuts for siding under the window
Position the siding to be notched below the window. Mark it on each side of the window, allowing an extra 1/4-in. gap on each side for expansion. Measure from the locking tab of the siding below to the undersill trim to determine the depth of the notch.
Maneuvering long pieces of vinyl into place can be tricky. Push one end of longer pieces into the trim, then bow the siding slightly and guide the other end into the trim.
Then slide it up and snap the butt into the locking edge of the piece below. Feed the shorter pieces alongside the window into the channel at the top of the window, and slide them down into position. Installing the piece above the window (Photo 15) was especially tricky because it was also the last piece (it would have been easier to remove one more course above).
We had to cut the piece and put a joint directly above the window. Then we cut a long length of extra siding to complete the row. Be sure to overlap butt joints 1 in. This method wouldn't work if you had to splice in new vinyl, because the colors wouldn't match.
Matching your siding
Remove a piece of siding and identify it. Take it to a siding retailer or distributor. They'll identify the brand and style and should be able to direct you to the right source. Unfortunately, vinyl siding fades with age, so an exact color match may be impossible.
Be sure to save and reuse all the siding you remove. The trim pieces aren't as critical. If you have to add new siding, position it in an obscure spot, like the base of a wall or behind the garage. In fact, you may want to re-side an entire wall with new vinyl.