How to Cover the Front Edge of Stair Treads

Built-in Bullnose Treads

• Available for purchase at home improvement stores are premanufactured bullnose treads. These are made a little thinner than a normal 1-inch tread; they have nosing with a full-width bullnose detail along the leading edge. Trim the backside of the treads to the proper width for your individual needs, then install them with a few well-placed casing nails into each stringer, setting the nails with a punch. While you can lap these right over the existing treads, close attention will need to be paid to your math if you do this, as doing this will change the rise of the steps by their individual thickness. A well-placed cove molding under the bullnose up against the riser beneath the nosing will hide the transition, but the mathematical discrepancy will still need to be reconciled at the top and bottom of the run.

Milling a Custom Radius

• The most solid method, but probably the most labor-intensive, is to round over the leading edge of the tread with a shaper table or router to create a custom bullnose. Once the thickness of the tread itself has been established, divide that number in half to get the radius you will use. For example, if the tread board is 1-inch-thick, you will need a 1/2-inch round-over router bit to create the bullnose. Remove the tread, then run it through a shaper table or mill it with a router on both sides and then sand it smooth. Make sure that there is enough of an overhang in the first place to accommodate the loss of material after the round-over is cut.

Applying a Bullnose Molding Strip

• One of the least expensive, but definitely not the strongest, of options is to apply a same-thickness strip of bullnosed molding directly to the face of the leading edge. This is only a viable option if the edge is not only squared off and flat but also very smooth and consistent. Purchase strips of bullnose molding of the same thickness and species, then cut to the length of your stair treads, including any mitered returns you wish to add around each tread. Next, clean the interface between the parts with a sander and add a bead of wood glue, then predrill some holes to accommodate a series of 3-inch casing nails, which you then drive all the way in and sink with a nail punch. Sanding the transition along with the rest of the tread prior to staining will help minimize the gap and reduce any possible tripping hazard. Finally, add a cove molding beneath this detail that overlaps the seam of the bullnose to help support the nose. Glue both backside faces of the molding prior to nailing it in place as well.

Trim and Finish

• Beneath any of these options you should consider the addition of molding. It not only adds to the detail and beauty of the front view of the staircase, but in some cases it adds strength to the nosing as well as provides a smoother transition between the riser and the bottom of the next tread. This becomes very important if the tread has a prominent overhang, as one major cause of personal injury and damage to the stairs is the catching of your toe on the way up the stairs and tripping. A prominent, yet smooth-shaped trim detail -- such as a cove or a quarter-round -- under the nosing helps to alleviate this effect. This is also the best means for hiding any shimming that may need to take place under the tread to level it off of the stringer framing. Putty all the nail holes, then sand and stain to taste.