What Is the Purpose of a Threshold On a Door?

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What Is the Purpose of a Threshold On a Door?

Door thresholds serve a variety of functions. Each one contributes to making your home more comfortable to live in.

A door threshold is a water barrier.

This is the chief reason door thresholds are installed in outer doorways. Water seepage can:

  • Be an inconvenience as you are constantly having to mop it up.
  • Pose a safety hazard as it makes the floor slippery.
  • Cause damage to the home’s building material. This leads to unplanned and costly repairs.

A door threshold levels out uneven flooring.

It can be a challenge to get flooring to meet seamlessly in a doorway. This is especially true in cases where a different type of flooring is in each room. The door threshold helps to achieve a smooth transition as the flooring goes from one room to the next.

A door threshold can be a decorative addition to a room.

Door thresholds tend to go unnoticed because they can blend in so well with the floor. However, some door thresholds are more conspicuous. They can add a decorative element to both rooms.

A door threshold helps create a weatherization seal.

It does this by working with the door sweep or other type of door seal used at the bottom of the door. Together they seal the gap between the floor and the door bottom. 

In the winter, this helps to stop cold air from entering your home while keeping warm air inside. It does the opposite in the summer.

Thus, it lowers your energy costs year round. You could see savings in the region of $300 as pointed out by Energy.gov in 2018.

A door threshold stops bugs and vermin.

Cockroaches, mice, and other creepy crawlies are small enough to fit under a door. Reducing the amount of space with a door threshold helps to keep them out. An even better barrier is formed when the door threshold is paired with a door seal.

A door threshold helps to keep out unwanted light and noise.

Light and noise can trickle through gaps into your home. They can become a real nuisance. They can prevent you from getting rest, relaxation, and privacy in your own space.

Do I Need a Door Threshold?

Having looked at the variety of purposes a door threshold serves, it is easy to see why they are used. Do a quick audit of the doorways in your home to see whether door thresholds are already installed.

  • If they aren’t, determine where they could be used to improve energy efficiency. Or, could they eliminate a persistent water seepage or pest problem?
  • If the doorways already have door thresholds, inspect them to see whether they are in need of repair. Door thresholds are exposed to plenty of wear and tear, so they will become scuffed or damaged over time.

How to Choose a Door Threshold

Several factors will impact the kind of door threshold you choose. Let’s take a look at each of them.


Where the door threshold will be placed is an important factor to consider. The amount of water exposure and foot traffic it will have to endure are directly related to its location.


In most conditions, an aluminum door threshold will prove to be more durable than one made of wood. Added to this is the fact that aluminum door thresholds are easier to clean. This makes it easier to keep them looking attractive.

Wood does have the benefit of giving a warmer, more natural feel to a room. Plus, wooden door thresholds can be stained to match the room’s décor. On the other hand, wood has a tendency to warp from prolonged water exposure. This will lead to a more frequent need to replace your door thresholds.


Door thresholds come in various heights. One that is too low will not fill the gap under the door. One that is too high will interfere with the opening and closing of the door.

 The Daoseal aluminum door threshold shown here has quite a low profile at only 16.5 mm high.

How to Replace a Door Threshold – Five Easy Steps

Replacing an aluminum door threshold is a DIY-friendly task. Tools needed are a tape measure, screwdriver, pry bar hacksaw, file, drill, metal bit, and a pencil,

Take out the old door threshold.

Find the mounting screws of the old door threshold. They may be hidden under a strip of rubber in the middle of the door threshold. Loosen the screws and remove the old door threshold. Use a pry bar if it is stuck in place.

Prepare the area for the new door threshold.

Remove all dust and debris from the space where the new door threshold is to be installed. This will ensure it fits snugly without any gaps.

Measure and cut the new door threshold.

Measure the new door threshold to match the old one. If it is too long, use a hacksaw to cut off the extra amount. Drill screw holes in the new door threshold if it does not have pre-drilled ones.

In cases where the new door threshold is identical to the old one, divide the extra length by two and remove this new amount from each end. This ensures that the screw holes will line up and there will be no need to drill new holes.

Install the new door threshold.

Simply screw in the new door threshold if the screw holes match up. If they don’t, rest the new door threshold in place and mark the screw positions with a pencil. Remove the door threshold and drill starter holes for the screws. Screw the new door threshold in place.

Double-check the fit.

Inspect the edges where the new door threshold meets the floor and the door jamb. If there are gaps, use rope caulk to ensure a secure seal.

Also, check out this 2- minute video for a visual guide for installing a door threshold.

Bottom Line: Are Door Thresholds a Necessity?

Door thresholds carry out several important functions that are oftentimes overlooked. They are a necessity, however, if you’re focused on weatherizing your home. They help you achieve maximum comfort and energy efficiency.

Inspect your home to see where door thresholds need to be replaced or installed. Then go ahead and select the right door thresholds for your home.