How should new hardwood be attached to an existing stair case?
When installing hardwood or finished wood over an existing stair, be aware of any change to the height of the top and bottom risers. Be sure to allow for this if the hardwood isn't going over the top and bottom floors, as well. Remove any existing hardwood or carpet down to the plywood treads. If there is any nosing or overhang on the plywood treads, remove them by cutting the nosing flush with the riser. Re-nail or screw your plywood treads securely. Also check your stringers to be sure they are in good shape. It is easier to replace or repair them now rather than later.
If you are putting in finished risers as well, put them in before the treads. Make the top of the riser flush with the upper plywood tread to help support the nosing. That is, the tread will be supported by the riser below it. You will have to purchase a nosing to match your treads, in tongue and groove and thickness. You can also buy pre-fab treads with nosing attached.
First, cut the nosing to length for the particular stair tread. Place it temporarily in position on the tread and scribe a line at the back of the nosing on the existing tread. Remove this nosing and calculate the width of piece you need at the back of the tread (it usually needs to be ripped). Then install the pieces from the back (tight against the riser) towards the nosing. Notice that the nosing has the same matched groove as the flooring's tongue, so orient the flooring strips so the tongue is towards the nosing. For a wide tread you probably will need the nosing plus 3 pieces of hardwood plus the ripping of about 1" or so, depending on the width of the strips.
These strips are nailed in as is the floor, through the tongue. The back strip or two, can be face nailed. Use no glue on the strips. Fit these pieces snug to the sides of the stairs, no expansion joints here. Then when all the strips are installed the nosing can be slid in. Use glue here to hold the nosing securely and in the tongue and groove of the nosing and its matching flooring strip. Nail through the face of the nosing with some finish nails every 6" and set them below the surface to be filled. If the flooring is pre-finished and the nosing is not, sand the nosing down before installation so it is flush with the flooring.
Apply a urethane finish over the nosing and new treads, after a light sanding.
Dave(Ask Dave) (About Dave)
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