How to Install a Threshold

A door threshold bridges the gap between rooms, sealing the doorway. It is designed to prevent objects and water coming under the door, and helps to reduce drafts. Installing a threshold is simple using these steps.

Step 1 — Measure Depth

If you do not want to get involved with alterations to the door, measure the amount of space between the bottom of the door and the floor. This gap will be the maximum thickness of the threshold.

Step 2 — Measure Width

Measure the internal width of the door frame at floor level. This will be the length of the threshold.

Step 3 — Make the Threshold

Thresholds can be simple and uniformly flat, or they can be beveled so that the edges are lower than the center. This is known as a "disabled" threshold because it is wheelchair friendly. A simple threshold design has a rectangular profile and can be cut from a suitable piece of timber the right width and thickness. If a beveled threshold is required, it is easier to buy the correct length of ready formed timber.

Step 4 — Finish the Threshold

Finish the threshold in the style and color that you have decided will fit in with the location. If you are using varnish, stain, or paint, prepare the surface with a fine sandpaper. Apply the finish in at least two coats, allowing each coat to dry before applying the next coat. Cover the ends as well as the top and sides.

Step 5 - Double-Check Dimensions

Double check the dimensions by putting the threshold in the position it will occupy and ensure that the door swings freely.

Step 6 - Glue

Once you have confirmed that the threshold is a good fit you must decide if it's necessary to glue it down. If the floor is marble, impact adhesive is often the easiest way to fit it. However, against a wooden floor it is not necessary to use an adhesive. Only glue a threshold down if there is no alternative.

Step 7 - Apply the Adhesive

If you have decided to use an adhesive, apply this to the threshold and the floor as per the instructions, and fit the threshold in place. Immediately test to ensure that the door still swings freely.

Step 8 - Weight the Threshold

If the door swings freely, put something heavy on the threshold to compress the adhesive and squeeze out any air pockets that might be trapped. Make sure it doesn't slip out of position.

Step 9 - Use Wire Nails

If you're not using adhesive, position it and ensure that the door swings freely Next, secure the piece in place with three or four wire nails.

Step 10 - Screws and Pilot Holes

The threshold should be fixed to the floor by brass screws. Even distribution, say, one every 6 inches is pleasing to the eye. Drill pilot holes for each screw to make the job easier, and to prevent splitting either the threshold or a floor board.

Step 11 - Counter-Sink

Counter-sink each pilot hole in the top of it using the counter-sink bit and drill. The bit will widen the top of the pilot hole and create a shoulder that is at the same angle from horizontal as the base of the head of the screws. When driven home, the screw head will be just below the level of the surface.

Step 12 - Secure

Ensure each screw is driven through the threshold and into the floor without creating a gap between the two. If this proves impossible, make the pilot hole just big enough to accept the screw.

A properly fitted threshold should last many years and help cut down on penetrating drafts, dirt, and water. Regular cleaning will keep it in good condition.