Here are the tools you'll want to have to make a weathertight threshold around doors:

• Small flat pry bar or putty knife
• Backsaw
• Chisel
• Hammer
• Screwdriver
• Replacement threshold
• Door sweep
• Tape measure
• Pencil
• Nails
• Drill

Many of the metal types feature a flexible vinyl insert that creates a tight seal when the door closes against it. Other thresholds consist of one unit on the floor and a mating piece on the bottom of the door. These two pieces interlock to form a weathertight barrier.

In most cases, the threshold with a flexible vinyl insert is the easiest to install. Interlock systems are quite effective when properly installed, but they require a perfect fit or they will not work satisfactorily.

Wooden thresholds often wear down to the point where they must be replaced. This is an easy installation, and there are many types of replacement thresholds from which to choose. Most are aluminum and come in standard door widths; however, if your door is not standard width, you can trim the aluminum threshold with a hacksaw.

Step 1: Remove old threshold. If it is wood, there are two ways to remove it. In most cases, you can pry it up after removing doorstops with small flat pry bar or putty knife, but you must work carefully and slowly. If jamb itself rests on threshold, saw through old threshold at each end. Use backsaw placed right against jamb, and saw down through threshold, being careful not to scar floor. Once you make cuts, threshold should be easy to pry up. If prying doesn't work, use chisel and hammer to split piece. Metal thresholds are frequently held down by screws concealed under vinyl inserts. Once you remove screws, threshold will come up easily. A door sweep can create a tight seal when a gap exists between the bottom of the door and the threshold. Door sweeps can be made of wood and felt, wood and foam, or metal and vinyl. All are effective in sealing out drafts.

Step 2: Install replacement threshold by driving screws through metal unit and into floor. If you don't want aluminum threshold, cut replacement from wood, using original one as pattern.

Step 3: Install door sweep to seal gap. Most sweeps are attached to inside of door with nails or screws. Cut sweep to size, and close door. Tack both ends of sweep to door, then install remaining nails or screws. If you are using screws, drill pilot holes first.

Some types of sweeps slip under the door and wrap around the bottom. Still another type fits on the outside, with a section of it flipping upward to miss the threshold when the door is opened. When the door is closed, this section flips back down to provide a seal against the threshold. You can adjust this type of door sweep so it renders a snug fit.

Weatherstripping and weather-proofing your doors -- and the rest of your home -- can help keep you comfortable when the weather is inclement. And the good news is that you can make these improvements to your home without having to call a professional.