Removing worn tread

Stairs shouldn’t need major repairs but sometimes the front of the tread, called the nosing, becomes excessively worn in the centre.
Use a jigsaw to cut out the rounded worn area, making angled cuts at each end of the repair.
Take care not to cut into the riser.
Cut and fit new wood stair nose

Cut a new piece of hardwood to fill the recess, angling the ends to match the ends of the repair. You can use a square section of wood and shape it later.
Screw and glue the new piece on to the tread, using 50mm countersunk screws.
When the glue has set, plane and sand the front of the new section to match the existing tread. Conceal the screw holes with filler.