How to Fit Door Threshold Strips

Door threshold strips are a simple but highly effective way to improve how your door performs. Whether you’re trying to stop draughts, cover a floor gap, or create a clean transition between rooms, fitting a threshold strip is a straightforward job when done correctly.

This guide will walk you through the process step by step, including preparation, measuring, cutting and fixing — along with the small details that make the difference between a quick fix and a professional finish.

How to Fit a Door Threshold Strip

What Is a Door Threshold Strip?

A door threshold strip is fitted at the bottom of a doorway to:

  • Cover the gap between two floors

  • Create a smooth transition between different floor levels

  • Reduce draughts and heat loss

  • Improve the overall appearance of the doorway

They are commonly used between rooms (e.g. carpet to laminate) or at external doors.

 

Types of Threshold Strips

Before fitting, it’s important to know which type you’re working with.

Flat threshold strips

  • Used between floors of the same height

  • Often used for carpet-to-carpet or laminate-to-laminate

Ramp (or reducer) strips

  • Used where there is a slight height difference between floors

Door bars (carpet threshold strips)

  • Designed to grip carpet edges and create a neat finish

Weather bars / external thresholds

  • Used on external doors to prevent draughts and water ingress

The fitting method is similar, but the purpose affects positioning.

 

Tools You’ll Need

  • Tape measure

  • Pencil

  • Hacksaw or fine-tooth saw

  • Drill and drill bits

  • Screwdriver

  • Fixings (screws or plugs, often supplied)

Optional:

  • Adhesive (for stick-down strips)

  • File or sandpaper (to smooth cut edges)

 

Step 1: Measure the Doorway

Start by measuring the width of the doorway where the threshold will sit.

  • Measure from one side of the door frame to the other

  • Take the measurement at the floor level

  • Double-check for accuracy

This ensures the strip will fit neatly without gaps.

 

Step 2: Cut the Threshold Strip to Size

Most threshold strips come slightly longer than needed.

  • Mark your measurement clearly on the strip

  • Use a hacksaw or fine-tooth saw to cut to size

  • Cut slowly to avoid rough edges

After cutting, smooth the edge with a file if needed.

 

Step 3: Position the Threshold Strip

Place the strip in position before fixing.

For best results:

  • Centre it under the door where possible

  • Ensure it covers the gap evenly

  • Check that the door can open and close without catching

For external doors, position the strip so it helps seal against the bottom of the door.

 

Step 4: Mark Fixing Points

Most threshold strips have pre-drilled holes.

  • Place the strip in position

  • Mark the fixing points onto the floor

  • Remove the strip

If there are no pre-drilled holes, space fixings evenly along the length.

 

Step 5: Drill the Floor (If Required)

Drill pilot holes at your marked points.

  • Use appropriate drill bits depending on your floor type

    • Wood floors: standard wood bit

    • Concrete floors: masonry bit + wall plugs

This ensures secure fixing and prevents splitting.

 

Step 6: Fix the Threshold Strip in Place

Position the strip back over the holes and secure it.

  • Insert screws and tighten evenly

  • Do not overtighten, especially with aluminium strips

If using an adhesive-backed strip:

  • Clean the floor thoroughly

  • Peel and stick firmly into place

  • Apply pressure along the full length

 

Step 7: Test the Fit

Open and close the door several times.

Check that:

  • The door moves freely without catching

  • The strip sits flat and secure

  • There are no gaps or movement

If needed, adjust slightly before fully tightening.

 

Tips for a Professional Finish

Ensure a tight fit

A well-cut strip should sit snugly between both sides of the doorway.

Match the flooring

Choose a finish that complements your flooring for a cleaner look.

Keep it level

Uneven strips can affect door movement and look untidy.

Use the right fixings

Different floors require different fixings — always match them to the surface.

 

 

Common Problems and How to Avoid Them

Threshold strip too short

Always measure carefully before cutting — you can’t add length back.

 

Door catching on the strip

This usually means the strip is too high or incorrectly positioned. Reposition slightly or choose a lower-profile strip.

 

Loose threshold strip

Check that:

  • Correct fixings were used

  • Holes are deep enough

  • Screws are tightened evenly

 

Poor alignment between floors

Make sure the strip is centred and covering the transition evenly.

 

When Should You Fit a Threshold Strip?

You may benefit from fitting one if:

  • There is a visible gap between floors

  • Flooring types change between rooms

  • You feel draughts under the door

  • You want a neater, more finished doorway

 

Final Thoughts

Fitting a door threshold strip is a simple job that can make a noticeable difference to both the look and performance of your doorway.

The key steps are:

  1. Measure accurately

  2. Cut cleanly

  3. Position carefully

  4. Fix securely

Taking your time with preparation and positioning will ensure a clean, long-lasting result that improves both comfort and appearance.