Door thresholds may look like just a small piece under your door, but they do a big job. The right door threshold seals the gap between the door and the floor, limits drafts, blocks pests and bugs, and helps prevent water infiltration around exterior doors. In this guide, you will learn what door thresholds are, which materials to consider, how to select and install them, and when to replace an old threshold.
Have questions or want a pro measurement in the Baltimore area? Call Master Seal at 855-606-8293 or visit our contact page for a free estimate.
Introduction to door thresholds
A door threshold is the transitional piece that lies across the bottom of the doorway, covering the sill and meeting the underside of the door. Think of it as a durable strip that creates a smooth bridge between inside flooring and the porch or exterior landing. A well installed exterior door threshold helps keep water out during heavy rains, reduces drafts, and supports energy efficiency by sealing the lower edges of exterior doors.
When sized and installed correctly, thresholds and their companion seals or weatherstripping limit air movement at the doorway, which improves comfort and can reduce energy use. A quality door threshold also protects the subfloor and the sill from moisture, which can extend the life of your exterior door. For more on sealing strategies, see the Department of Energy’s weatherstripping guidance.
Types and materials: wood, aluminum, vinyl, and more
Door thresholds come in several materials and profiles. The best choice depends on your door, your climate, and your home’s style.
- Aluminum thresholds, durable and corrosion resistant, are common on residential exterior doors. Many aluminum thresholds include adjustable screws to fine tune the height for a tight seal against the door bottom.
- Wood thresholds, classic and warm, can be stained or paint matched to trim. Wood needs periodic sealing or paint to resist weather, especially at high traffic front entryways.
- Vinyl thresholds, lightweight and affordable, resist moisture and are simple to cut to fit. Some combine vinyl with an aluminum cap for extra strength.
- Bronze finishes are popular for traditional homes, and you can choose oil rubbed bronze colors to match handles and trim.
- Specialty types include saddle thresholds, low profile ADA style thresholds, and combination bulb threshold designs that integrate a compressible gasket or door shoe for extra weather protection.
Selecting the right door threshold for your home
Use these criteria to find the right threshold for your exterior door:
- Compatibility: Match the threshold to your door material and flooring. For example, a steel entry door with tile floors may need a slightly taller profile than a wood door meeting hardwood floors.
- Durability and weather: Choose materials that stand up to rain, snow, and high foot traffic. Aluminum and bronze finished options handle outdoor exposure well.
- Energy performance: Look for designs that work with door sweeps and weatherstripping to seal air and water. Many exterior door threshold systems include replaceable gasket inserts.
- Style: Select colors and trim details that complement your house.
How to measure, step by step:
- Measure the width of the door opening between jambs.
- Check the sill depth and note thickness and any slope.
- Measure flooring height inside and the porch or landing height outside.
- Choose a stock size that you can trim to fit, or order exact sizes if the opening is unique.
A good fit creates a flush, smooth transition that reduces the chance of trips. Some thresholds include integrated door stops or adjustable screws near the edges to fine tune the seal at the gap along the door bottom.
Threshold installation and maintenance for exterior doors
A careful installation helps your threshold seal well and last a long time.
Step 1: Prepare the subfloor and sill. Remove debris, old adhesive, or nails, then check that the sill is level. Dry fit the threshold before you fasten it.
Step 2: Align and lay the threshold. Center the piece so its edges meet the jambs, and make sure the strip sits tight to the floor inside and the porch outside.
Step 3: Fasten with the right tools. Pre-drill if needed, use corrosion resistant screws, and tap gently with a rubber mallet to seat the threshold. If your model includes gaskets, watch that they do not twist as you tighten. Run a thin bead of exterior grade sealant along the exterior seam for added water protection.
Step 4: Check for a flush seal. Close the door, look for light at the gap, and adjust any screws. Confirm the door opens freely and clears the threshold and any door stops or sweeps.
Maintenance tips:
- Clean dirt and grit that can wear the seal.
- Inspect weatherstripping each year and replace worn inserts.
- Re-seal wood with paint or clear finish as needed.
- Tighten loose fasteners and fix damage early.
For more installation best practices and performance labels on exterior doors, see ENERGY STAR windows, doors, and skylights.
Replacing and upgrading an old threshold
If an old threshold feels spongy, lets in air, or shows water damage at the sill, it is time to replace it. Upgrading to an aluminum threshold with a built-in gasket can improve sealing and help keep pests outside.
To replace a threshold:
- Remove the old threshold; pry carefully and clean the surface.
- Measure again and check sizes for the new one.
- Dry fit, then attach and seal as described above.
- Install compatible weatherstripping or a door bottom sweep, then test the seal.
Ready to replace your front door threshold or upgrade a back entry? For a free estimate, call Master Seal at 855-606-8293 or visit our contact page.
Door threshold FAQs
Can I replace the threshold on an exterior door myself?
Yes, DIY is possible for many homeowners, but complex doorways or out-of-level sills may benefit from professional help.
What is the best type of threshold for an exterior door?
The best option depends on your needs. Aluminum thresholds are popular for durability and low maintenance, wood offers a classic look you can stain or paint, and vinyl works for simple, budget friendly projects.
How much does it cost to replace a door threshold?
Costs vary with materials, sizes, and labor. Vinyl is often the lowest cost option, wood sits in the middle with ongoing maintenance, and premium aluminum thresholds with adjustable features cost more in the short term but can save time and reduce drafts over the year, ultimately saving energy costs.
What is the difference between a door sill and a threshold?
The sill is the horizontal base of the doorway, often part of the frame structure. The threshold is the piece you see and step on; it bridges across the sill and helps the door’s seals keep out air and water.
