Things You'll Need
Hammer and wood block or rubber mallet
3/16-inch rotary bit
1/8-inch wood bit
Pencil or felt tip pen
A threshold is the plate at the bottom of every modern exterior door that rests directly beneath the door when it is in its closed position. Also known as a door saddle, this piece of hardware's main purpose is to provide a weather-tight seal for the bottom of the door. When replacing thresholds installed on tile floors you will need to make sure that you have a sharp rotary mason's bit to cut through the tile.
Preparing to Install
Remove the old threshold. Tap the end of a flat pry-bar under one end of the threshold and pry it up away from the floor. Lift the threshold out of the door frame and set it aside to be used as a pattern for cutting the new threshold.
Cut the new threshold to the same length as the original. Use a hacksaw to make the cut. Set the original on top of the new threshold and mark any end notches onto the new threshold. Cut these notches out with a hacksaw. Use a file to smooth off any burrs along the edges.
Examine the floor where the old threshold was pulled up to determine if you are installing onto a concrete sub-floor or a plywood or other wood-based floor. Look at the dust in holes left by the old nails or screws. If it is gray and chalky, you have a concrete sub-floor. If it is sawdust, you have a wood-based sub-floor.
Set the threshold into position. Use a rubber mallet or hammer and wood block to tap it into place if needed. Locate the mounting screw holes in the top of your threshold.
Mark through the screw holes with a pencil or sharp felt-tip pen. Make sure to mark every hole. Lift the threshold out of the bottom of the door frame and set it aside so you can see the marks.
Installing on Concrete Sub-Floors
Drill through the tile with a 3/16-inch rotary mason's bit. Continue drilling into the concrete to a depth of 2 ½ inches. Wrap a piece of masking tape around the bit 2 ½ inches from the tip of the bit to mark the depth. Blow the dust from the holes.
Set the threshold back in place, tapping it down with a mallet or hammer and wood block carefully to avoid scratching the jamb.
Drive one 3-inch tapcon style concrete screw into each hole. Drive them in until the screw heads press the threshold firmly down.
Installing on Wood Sub-Floors
Drill through the tile with a 3/16-inch rotary mason's bit. When you reach the wood sub-floor stop drilling. Drill through the tile with the mason's bit in each marked location.
Install a 1/8-inch wood bit into the drill. Drill a 2 ½-inch pilot hole through each hole in the tile into the sub-floor. Wrap a piece of tape around the bit to mark the depth.
Set the threshold into position and drive one 3-inch treated deck screw through each hole in the threshold. Drive each screw in until it presses firmly against the threshold.