How to Replace a Door Sill

Co-authored by Ryaan Tuttle

Last Updated: March 24, 2023 References Approved

The door sill, or threshold, is the bottom portion of your exterior door frame. It helps to keep the elements out and provides a seal, as well as a place to step as you enter the home. These thresholds wear out over time, because of foot traffic and exposure to the weather. Replace them as needed to help keep your home's exterior in good condition.

Method 1

Method 1 of 2:

Replacing a Metal Door Sill

Some door sills are made of brass or other cast metal that is screwed into place.

1
Measure the existing door threshold for length and width.
2
Purchase a metal sill of the same size and shape.

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3
Use a variable speed drill fitted with a screwdriver bit to remove the screws anchoring the threshold into place.^{[1]
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4
Use a utility knife to cut through any caulk on the front and back edges of the sill.
5
Place the end of a pry bar beneath the threshold and pull up on the bar to pull the old threshold away from the door frame.^{[2]
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6
Lay the new threshold out on a flat surface and place the old one on top of it.^{[3]
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7
Use a pencil to trace the shape of the ends of the old threshold onto the new one. Most metal thresholds are cut to fit around the door jamb. Because each door jamb can be different in size, the threshold must be cut on site to fit.^{[4]
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8
Remove the old threshold and screw the new threshold down onto a work table to keep it from moving.^{[5]
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9
Use a jigsaw to cut out the shape of the door jambs from the ends of the new threshold.^{[6]
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10
Test the fit of the new threshold beneath the door and make sure the door closes over it.
11
Screw the new threshold into place.
12
Run a bead of waterproof caulk along the front and back edges of the threshold to help seal it into place.^{[7]
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Method 2

Method 2 of 2:

Replacing a Wooden Threshold

Other than metal thresholds, the most commonly used material for a door sill is a hardwood like oak. Wooden thresholds often come in standard lengths that can be trimmed to size on site.

1
Remove the door casings on either side of the doorway.
2
Insert the end of a pry bar behind the casings and gently tug them free. Set them aside for later.^{[8]
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3
Use a circular saw to cut the threshold into three pieces. Cut nearly to the bottom of the threshold, but do not cut all the way through to avoid cutting the toe kick.^{[9]
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4
Cut the rest of the way through the threshold with a handsaw for control.
5
Insert a pry bar beneath each section of the threshold and pull it free. If any section is not coming free easily, use a hammer and chisel to break it into pieces before prying it up.^{[10]
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6
Measure the length of the door sill and ensure that the new threshold is of equal size. Cut the new threshold to fit with a circular saw if necessary.
7
Slide the new threshold into place to ensure that it fits.
8
Paint the new threshold with a water and UV proof stain to help protect it from the elements. Allow it to dry.
- Alternatively, coat the new sill with 2 coats of clear polyurethane to seal the wood.
9
Slide the new threshold back into place.
10
Drill pilot holes into the threshold that are slightly smaller than the finish nails that will hold it in place. This will prevent the threshold from cracking as you drive in the new nails.^{[11]
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11
Hammer in the finish nails to hold the threshold in place.
12
Fill the nail holes with wood putty.
13
Reattach the casings on either side of the doorway.
14
Hammer the finish nails back into place to reinstall the casings.

Community Q&A

Question

I have a double metal door into a utility room in the basement of my home. The threshold base is a piece of wood which is badly rotted. There is a plastic strip attached to the wood base which is in a channel cut into the cement floor, about and inch and one half deep. How do I repair it?

Community Answer

Cut it all out and then replace the plastic and wood combination with a piece of plastic baseboard. You could also just cleanout the floor channel and fill it in with cement, keeping it flush with the floor or mounding it up to the doors. You can easily hand mound a drier cement mix, or you can even sort of stamp a rectangular shape with a homemade wood mold that you force down and squeeze out any excess cement.
Question

How do you know how to measure for a door sill pan?

Community Answer

A tape measure should work very well for most doors. For other situations, you can use 2 sticks or wood scraps. Push the sticks or scraps tight to the jambs where you'll be cutting the old sill out, and then just draw a line across both sticks or scraps. Then, take the sticks to a tape measure with the line re-aligned for a perfect and exact measurement.
Question

I have a double metal door sill to replace, can I do it the same as a single door?

Community Answer

Yes, if the doors just sweep on top of the threshold or both doors clamp on the same side of the threshold. No, if the doors open oppositely to each other and therefore clamp to different sides, you'll have to conversely ramp or round the sides appropriately and individually.

Warnings

Always make sure you replace the sill with one of the same size and shape, including thickness. Sills come in all shapes and sizes; your door may not close properly if you use a different sort.

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