How To Install a New Threshold

Installing a new threshold is an easy DIY home improvement project that can spruce up your entryway and prevent air and water leaks. In this video guide, we’ll walk you through the process of replacing an old threshold with a new one alongside This Old House general contractor Tom Silva.

What Are Thresholds?

Thresholds serve as a transition between the flooring on either side of a doorway. In an interior doorway, thresholds can bridge different types of flooring, and on exterior doors, a threshold can help protect against the elements.

A proper threshold can enhance the energy efficiency of your home and protect against water and pests from entering. A well-maintained entryway with a new threshold can eliminate uneven surfaces and gaps, so your door opens and closes smoothly—as well as boost your home’s curb appeal and overall value.

Types of Thresholds

There are several types of thresholds available, each designed for specific door configurations and weather conditions:

• Oak thresholds: Known for their durability and attractive appearance, oak thresholds are a popular choice for many homeowners. They’re ideal for areas with moderate weather conditions.
• Aluminum thresholds: These are lightweight and resistant to corrosion, making them suitable for coastal areas. They’re also easy to install and maintain.
• Adjustable thresholds: These versatile thresholds can be adjusted to fit different door heights and gaps, providing a custom fit for your entryway.
• Interlocking thresholds: Designed to create a tight seal, interlocking thresholds are excellent for preventing drafts and water infiltration.
• Thermal break thresholds: These include a barrier that reduces thermal transfer, improving energy efficiency and comfort in your home.

Preparing for Threshold Installation

Before you begin the installation process, you’ll need to gather the necessary tools and materials. You’ll also need to remove the old threshold before reinstalling the new one.  

Tools and Materials Needed

Our guide uses a new oak threshold, but you may want to opt for a different type. Gather the following tools and materials before you get started:

• 100-grit sandpaper
• 2-inch decking screws
• Caulk gun
• Chisel
• Drill/driver
• Expanding polyurethane sealant
• Exterior paint or stain with ultraviolet (UV) protector
• Hammer
• Measuring tape
• New oak threshold
• Pressure-treated lumber
• Reciprocating saw
• Tri-polymer caulk
• Wood shims

Removing the Old Threshold

Before installing the new threshold, you need to remove the old one. This process involves a few critical steps:

1. Use a chisel: Create a gap between the threshold and the floor by inserting a chisel under the edge of the threshold.
2. Insert the reciprocating saw blade: Carefully cut through any nails or screws securing the threshold in place.
3. Make two angled cuts on the top: These cuts will help the old threshold slide out more easily.
4. Remove the old threshold: Once the nails are cut and the top is beveled, you can remove the old threshold from the doorway.

Installing the New Threshold

With the old threshold removed, you can now proceed with installing the new one. 

Preparing the Subfloor

Before installing the new threshold, you should make the subfloor is adequately prepared by following these steps:

1. Remove the toekick: Use a reciprocating saw to cut the nails securing the toekick and remove it from the doorway.
2. Build up the subfloor: Add pressure-treated lumber to the subfloor and toekick area, providing additional support and stability.
3. Reinstall the toekick: Make sure the toekick is at the appropriate height to accommodate the new threshold.

Fitting the New Threshold

Now it’s time to install the new threshold:

1. Test-fit the new threshold: Place the threshold in the doorway to check for proper alignment and fit.
2. Make necessary adjustments: Modify the subfloor or toekick as needed.
3. Apply caulk: Use a bead of tri-polymer caulk to seal the joint between the finished floor and the new threshold, preventing drafts and water infiltration.

Securing the Threshold

Securing the new threshold involves ensuring it is level and securely in place. Follow these steps:

1. Place the threshold: Align the threshold in the doorway.
2. Insert shims: Use wood shims to level and support the threshold from beneath.
3. Check for an even gap: Close the door and check for a uniform gap along the threshold, adjusting shims as needed.
4. Apply sealant: Use expanding polyurethane sealant under the threshold for insulation and adhesion.
5. Secure with shims: Insert shims between the door bottom and the top of the threshold to hold it in place while the sealant cures. Tom Silva recommends waiting a few hours to remove the shims.

Finishing Touches on the Threshold

After installing the new threshold, a few final steps, including sanding and finishing, will improve its appearance and performance. Regular maintenance will keep it looking great for years to come.

Sanding and Finishing

To protect and enhance the appearance of your new threshold:

1. Sand the threshold: Lightly sand the surface with 100-grit sandpaper to smooth any rough areas.
2. Apply exterior paint or stain: Use a product that contains a UV protector to shield the threshold from sun damage.
3. Use a clear finish (optional): For added durability, apply a marine-grade polyurethane.

Maintaining Your New Threshold

Regular maintenance will keep your threshold in top condition. Regularly clean the threshold to prevent dirt and debris buildup. Inspect the threshold annually for signs of wear or damage, and reapply finish as needed to maintain protection against the elements.

Our Conclusion

Installing a new threshold is a manageable DIY project that can significantly improve your home’s energy efficiency and appearance. By following these steps and using quality materials, you can create a durable, weathertight seal for your entryway that will last for years to come.