Oil, wash, oil, wash, oil, oil and more oil. No matter how hard you try to protect outside wood structures, sooner or later cracking, splitting, cupping and shrinkage will occur. They are but a few of the ongoing conditions that eventually will affect your wood deck, porch, rails and stairs.

With porches and decks, shrinkage is expected and, therefore, is a normal and acceptable condition. However, with steps and guard rails, shrinkage can be a major problem. For a step or rail to be safe, it must be solid and stable. As wood shrinks joints and connections separate, and formerly firmly positioned parts become wobbly and dangerous.

At some point nails that once held connections solidly begin to loosen. You might assume that when wood shrinks, the holes surrounding the nails do likewise. Unfortunately, the opposite happens the holes get bigger and the nails lose their hold.

To make a strong repair that will hold things together for years even with shrinkage that would free a nail consider bolting loose connections. One way to repair stairs is to use metal L-brackets with through-bolts. Nothing is stronger than a nut and a bolt. If you don't have access to both sides of the area where the repair is to be made, use lag bolts. A lag bolt is nothing more than a giant screw with a bolt-type head and large threads that have about 10 times the holding power of a nail.

Because of a lag bolt's relatively large diameter, it is important to predrill before installing. Not doing so could result in splitting the wood. The pilot hole should be approximately three-fourths of the diameter of the lag bolt. For example, the pilot hole for a half-inch lag bolt would be three-eighths of an inch. Also, depending on the look you want to achieve, you might elect to countersink the head of the lag bolt. The countersink hole is drilled slightly deeper than the depth of the head of the lag bolt and about one-eighth of an inch greater in diameter than the size of the washer being used. For maximum holding power, a lag bolt should be accompanied by a washer. A washer prevents the bolt head from pulling through the surface of the wood. With washers, bigger is better. The biggest ones are called fender washers and are a must when building with or repairing soft species of wood, such as redwood and pine.

Also, it should be noted that drilling sequence is very important. Always drill the countersink hole first and the pilot hole second. If the pilot hole is done first, there will be nothing to stabilize the drill bit when the countersink hole has to be drilled.

In many cases all it takes to repair a set of stairs is to install a few bolts here and there. Before long the stairs and rails are stronger than ever. However, no lag bolt will hold a wood part that is rotted. Replacing a damaged stair tread is easy: Cut and remove the tread. If there are deep notches in the stair support rails (stringers), two cuts near the center of the stair might be needed. Hand rail and stair material should be made from higher grade material. But, regardless of the grade, make sure that the stair material is knot-free. And, whenever possible, bolted connections should be clamped together first. This puts less pressure on the wood during the installation of the bolt. If a clamp cannot be used, temporarily nailing the connection together also works.