Make Your Mark.
The first step is to determine just how far the damage goes and then locate the uprights or studs on both sides of the damaged area. Use a stud finder and/or look for patterns of small dimples in the wood (these dimples often indicate the heads of the nails attaching the siding to the studs). Once you've located the studs you'll be attaching the new siding to, make a mark on both ends.
Putting It In Place.
If your siding is overlapped and an undamaged piece rests atop a piece to be replaced, you'll want to gently pry up the edge of the good piece and work the nails loose. When you've got just a bit of the nail heads exposed, work your pry bar or the claw of a hammer to pry the nails out.
JANE TIP: While prying off an old or damaged piece of siding, use a shim (a small piece of thin scrap wood) under your pry bar to give yourself something to pry against without damaging more of your siding.
You'll now want to cut away the old siding. Making the actual cut can be tricky, because you're trying to avoid cutting into anything other than the damaged section. If you're replacing just a small piece (less than six inches square, you can probably use a hammer and chisel. If you're replacing a more substantial length, and you're comfortable making plunge cuts with a circular saw, you can cut a large section out in no time. Other cutting alternatives include a high speed cutting drill (Like a Rotozip), or even a jigsaw. It doesn't really matter which tool you use, just be sure to set the blade to no more than a 1/4" deeper than the thickness of your siding, so you minimize cutting into any studs, sheathing, or protective wrap.
If your siding is horizontally overlapped, stop your vertical cut just short of the overlap and make your cut on the other side. Then make a perpendicular connecting cut just below the overlap.
Now remove all that bad siding, but don't toss it yet—you'll need it to find a replacement in the same style and thickness.
JANE TIP: Once the old siding has been removed, take a good look at the area you removed it from and make sure it's not revealing a larger problem. Do you see dry rot, signs of termites or other pests, or significant water damage? If so, you need to figure out the cause—and do something about it. If you see evidence of a much larger problem, you may need to call in a pro. After all, if you don't fix the cause and just swap out a new board for the bad one, you'll likely end up with the same damage again (or worse) sooner rather than later.
Meet Your Match.
Take that piece of siding you pulled down to your local home improvement store to find a fit. Siding comes in all kinds of shapes and sizes; if you've got an older property or one that used unusual or custom milled boards, you'll likely stump the local lumber department, but they should be able to refer you to a siding supplier who's got a likely match. In the worst case, you'll need to find someone who can recreate your old style with a milling machine.
If all that sounds like too much trouble and expense, you can look around the house for a section of undamaged siding you can "borrow." Removing a piece of your existing siding from an inconspicuous spot (such as in the back of the house under a porch) to use as a replacement. You'll still need to replace what you steal from elsewhere, but if you take it from an inconspicuous spot, you can replace it with less than a perfect match.
A Perfect Fit.
Once you've located your new replacements, take careful measurements and cut the shape you need with a fine tooth blade for a smooth edge. Get the fit just right: too tight and it'll be difficult to put into place, too loose and the seam will be noticeable.
A Little Prep.
Now, prep the wood by sanding it smooth. You'll want to be sure that when you install it it's as level as possible with your existing siding. Apply a coat of primer. Finally drill pilot holes at the edges where they align with the studs; this will prevent your nice new siding from cracking when you go to attach it. Repair any torn sheathing paper with glue and you're ready to put that new board in place.
Slip the board in place and affix it to the studs with wood screws. You want to sure you sink the screws into the wood, so you can hide the heads with a touch of patching compound or exterior caulk.
TOOL TIP!: Drilling into hard, thick wood is a difficult task with most standard drills. One way to make this process easier is to use a hammer drill such as the Ryobi 18V 3 Speed Hammer Drill. Hammer drills use a 7quot;hammer-like" motion to get the job done. These drills are great for drilling into masonry and concrete as well (using the proper drill bit).
If you've got overlapping siding, you'll need to gingerly work the new boards under the old. Carefully pry the overlapping board up just slightly; use shims if necessary to gently pry the boards out and create a gap big enough to accommodate the new siding. Now slip the new board under the existing one and align it so it matches the existing pattern. If the new piece sticks, use a gentle persuasion with a hammer—but don't just whack away at the bottom of your new board—it's likely to dent or split. Instead take a 6" section of scrap wood, place it the long way on the bottom edge of the replacement board and pound the scrap-it'll distribute the force and ease that board right into place. If your new siding is a bit warped, you'll need to use a bit more pressure. Use your hammer drill to attach it to the studs making sure to sink the screws just below the surface.
A Once Over.
Now you'll want to be sure to check your seams to be sure the new piece blends in with the existing boards and that there are no distinct openings. Remember, water will make its way through any openings and cause further damage. Be sure to put a bead of exterior grade caulk down for further protection and let it dry according to the manufacturer's instructions.
Once you've made all necessary siding repairs, you're home might look a bit like a checkerboard—so now it's time to paint! Find out how to prep your home and then paint it by clicking here!