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Fixing Stairs

The staircases in your home have many parts—all of them interlocked with sophisticated joinery that is usually concealed from view. A pair of stringers (also called carriages) slopes from one level to the next. The stringers support a series of steps, called treads. A simple staircase—such as one that leads to a basement or deck— consists of little more than stringers and treads.

The illustration at right shows both “open-” and “closed-stringer” staircases. An open stringer has notches cut out of it; treads rest on the notches. A closed stringer has a series of grooves into which treads and risers fit. In most interior stairways, risers fill the vertical gaps between the treads. Risers give a more finished appearance, keep dirt and objects from falling to the floor below, and add strength. Finally, a balustrade—which consists of a handrail, balusters, and a newel post—provides safety along at least one side. Because all the parts are subject to various stresses, they all must fit tightly.

On most interior stairways, the balusters fit into the treads with dado, dowel, or dovetail joints. Balusters come in many styles, ranging from simple to ornate. On less-formal and outdoor stairways, the balusters may be attached to a bottom rail, which runs parallel to the railing a few inches above the treads.

Treads and risers. Interior stairway construction typically uses hardwood pieces milled to exact specifications and assembled much like cabinetry. Treads and risers usually fit together with dado joints. In some cases wood blocks provide additional support. In another arrangement (above right), treads and risers fit into grooves cut in a closed stringer. Wood wedges are tapped in and glued snug to the treads and risers.

Balusters. Balusters fit into grooves or holes in the underside of the handrail. At the stairway end, balusters often fit into holes in the stair treads. At the bottom of the stairway, a newel post is firmly anchored to the stair’s framing. If there is a wall on one side of the stairway, it may have a handrail, usually attached to special handrail supports that are anchored to studs in the wall.

Simple stairway. A stairway for a porch or a basement may consist of stringers and treads. Usually a loose tread can be firmed up by drilling pilot holes and driving new screws. Even the simplest stairway should have a solid handrail.

Tightening Rails and Balusters

Wobbly handrails call for detective work. Is the handrail working loose from the balusters, or are the balusters parting company with the treads or bottom rail? If the handrail is pulling away from a newel post, use the technique at right. A newel post handles a lot of stress. It is usually attached to the stringer, and may be attached to the house’s framing as well. Unless you see an obvious solution to a wobbling newel post, call in a pro for help.

Screw and glue. Drill a pilot hole at an angle through the baluster into the rail or tread. Countersink a trimhead screw in the hole. Alternatively, drill pilot holes through the railing and into the baluster. Work wood glue into the joint, and drive finishing nails or finishing screws.

Add blocking. If the entire railing is loose, add blocking as shown. Use a T-bevel and a miter box or a power miter saw to cut angles for a snug fit. Drill pilot holes, apply wood glue, and drive finishing nails or trimhead screws.

Silencing Stair Squeaks from Above

Most staircase squeaks result IVI from a loose tread rubbing against the top or bottom of a riser or a stringer. To locate the problem, watch as someone rocks back and forth on each tread. If the tread moves, it’s time to take corrective action. You can stop a squeak by forcing the tread either down or up, and wedging it firmly in place. A small problem can sometimes be solved using finishing nails. However, take care: If you drive a nail near the edge of a tread or riser, continued flexing of the riser could cause the wood to crack.

Work from below if you have access to the underside of the staircase. Otherwise you’ll have to attack the situation from above. A few well-placed nails, screws, or hardwood wedges will usually solve the problem. The directions enable you to repair several squeaky treads. If the stairway squeaks or groans at many points, however, the problem is likely structural. Go under the stairway and look for a cracked stringer, a closed stringer that is pulling away from the wall, or treads that are pulling away from a closed stringer. To correct a major problem, call in a pro.

Powdered graphite. Lubricating squeaks with powdered graphite may quiet them, but only temporarily. Squirt graphite into suspect joints and wipe away any excess graphite.

Drive nails or screws. If the front of a tread is loose and you don’t mind the appearance of small holes in the tread, drill pilot holes at opposing angles. Drive in ring-shank flooring nails or trimhead wood screws. Countersink the fastener heads and fill with wood putty.

Install glued wedges. If the tread is loose at the back, coat hardwood wedges (not softwood shims) with glue, tap into place, and let dry. Cut off exposed wedge ends with a utility knife or a chisel.

Add quarter-round molding. For uncarpeted stairs, you can tighten joints with molding. The larger the molding, the better - 3/4-inch quarter round works well. Apply glue, drill pilot holes, and drive finishing nails into both risers and treads. Use a nail set to sink the nail heads.

Silencing Stair Squeaks from Below

Usually repairs made from underneath the stairs will be stronger and more durable than repairs made from above. The problem is getting there. Stairs leading to a basement may be exposed on the underside. Most other interior stairs are not so easy to access.

Gaining Access - Removing one or more treads or risers may give you enough room to work. Because one stair part is often set into another part’s groove, disassembly is often difficult. But as long as one side of the stairway is open, you should be able to take things apart. Often it helps to cut through nails or screws using a reciprocating saw. When you reassemble the stairs after the repair, the last tread will probably need to be fastened from above. If the area under the stairway is covered with drywall and extensive repairs are needed, consider removing the drywall, even though replacing and finishing the drywall will be a substantial job.

Tighten with hardwood blocks. Purchase a length of 2x2 oak, birch, or other hardwood, and cut it into pieces about 4 inches long. Drill four pilot holes, running in two directions. Where a tread or riser needs support, apply wood glue to the wood block, press it firmly in place, and drive wood screws to fasten it. Make sure the screws are not long enough to poke through the surface of the tread.

Use angle brackets for a loose tread. If the entire tread is loose, use two or three metal angle brackets to tighten it down to the riser. Small brackets act much like wood blocks; larger brackets support the entire tread.

Replace loose wedges. If old wedges are loose, remove and replace them. If a wedge comes out easily and in one piece, apply wood glue and hammer it back tightly into place. If a wedge is stuck but not supporting the stairway, chisel it out and replace it with a new wedge.

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