Choosing the Right Door Threshold
A door threshold is fitted across the bottom of a doorway and forms the transition between the door and surrounding floor or external surface.
The correct threshold can help create a more complete door assembly while providing the necessary interface between the bottom of the door, weather seals and floor.
When choosing a threshold, consider the door opening direction, under-door clearance, door thickness, exposure level, threshold height, accessibility requirements and whether the installation is a single or double door.
Inward & Outward Opening Doors
The opening direction of the door is one of the first things to check when choosing a threshold.
Some threshold profiles are specifically designed for inward-opening doors, while others are intended for outward-opening doors. Selected systems can accommodate either arrangement.
Using the correct configuration helps ensure that the door, threshold and surrounding seals work together correctly.
Always check the individual product specification before ordering.
External Door Thresholds
An external door threshold forms an important part of the transition between the inside and outside of a building.
For exposed entrance doors, the threshold should be selected according to the anticipated weather exposure as well as the door construction and surrounding seals.
Some thresholds in the Roundtower Hardware range are designed for moderately exposed locations, while selected OUM profiles are suitable for more severely exposed applications.
The complete weather performance of an entrance should always be considered as a system rather than relying on the threshold alone.
Accessible & Low-Level Thresholds
Threshold height is particularly important where ease of access is required.
A lower and suitably profiled threshold can help create a smoother transition for wheelchairs, mobility aids, pushchairs and pedestrian traffic.
Selected thresholds within our range are specifically suitable for wheelchair access.
Where accessibility requirements apply to a project, consider the complete doorway arrangement, including the threshold height, surrounding floor levels and the operation of the door.
Thresholds for Double Doors
Double and French-door arrangements can require additional consideration at threshold level.
Selected threshold systems can accept striker blocks for flush bolts, allowing the inactive door leaf to be secured into the threshold.
This can provide a neater and more integrated arrangement than trying to form a separate fixing point within the floor.
Always check that the striker block and threshold are compatible with the particular flush bolt and door system.
Understanding Under-Door Clearance
The under-door clearance is the space between the bottom edge of the door and the finished floor or threshold position.
Different threshold profiles are designed around different clearances, so this dimension should be checked before ordering.
For example, some systems are intended for approximately 12–13mm under-door clearance, while other profiles may require a different arrangement.
Accurate measurement is particularly important when replacing an existing threshold or working with a completed door set.
Aluminium Door Thresholds
Aluminium thresholds are widely used because they provide a durable, practical profile without adding excessive weight or bulk at the base of the door.
They are particularly common on external and commercial entrances and can be combined with compatible seals and door-bottom hardware where required.
Roundtower Hardware stocks aluminium threshold profiles in finishes including Mill, Gold and selected Black options, allowing the threshold to complement the surrounding door furniture.
Thresholds & Door Seals
The threshold is only one part of the sealing arrangement around a door.
Depending on the application, it may be combined with drop seals, weather seals or other perimeter seals to help control draughts, water penetration, light or sound transmission.
It is important to ensure that the threshold and door-bottom seal are compatible and that sufficient clearance remains for the door to operate correctly.
Frequently Asked Questions
What is a door threshold?
A door threshold is a profile fitted across the bottom of a doorway.
It creates the transition between the door and floor while providing a defined surface for the bottom of the door and associated seals to meet.
How do I choose the correct door threshold?
Check the door opening direction, door thickness, under-door clearance, exposure level, required threshold height and overall doorway width.
For double doors, also consider whether a flush-bolt striker needs to be incorporated.
Are door thresholds suitable for external doors?
Yes. Many threshold systems are specifically designed for entrance and external doors.
The correct product should be selected according to the level of weather exposure and the complete door-sealing arrangement.
What is an accessible door threshold?
An accessible threshold is designed to minimise the obstruction at floor level and provide an easier transition through the doorway.
Selected thresholds are suitable for wheelchair access, but the complete doorway and surrounding floor levels also need to be considered.
Can a threshold be used with double doors?
Yes. Certain threshold systems are particularly suited to double doors and can accept compatible striker blocks for flush bolts.
Always check the individual threshold specification before ordering.
What is the difference between a threshold and a drop seal?
A threshold is fixed at floor level, while a drop seal is normally fitted to the bottom of the door.
An automatic drop seal lowers when the door closes and retracts when the door opens. The two products can sometimes be used together as part of a complete door-sealing system.
Can door thresholds be cut to size?
Aluminium threshold profiles can often be cut to the required doorway width during installation.
However, always check the product design and supplied components before cutting, particularly where end pieces, seals or striker blocks are involved.
What finish should I choose?
The finish is largely an architectural choice.
Mill Aluminium provides a straightforward functional appearance, while Gold and Black options can be selected to better coordinate with the door and surrounding architectural ironmongery.
Need Help Choosing a Door Threshold?
The correct threshold will depend on your door type, opening direction, under-door clearance, exposure level and accessibility requirements.
Roundtower Hardware supplies door thresholds in Ireland for residential, commercial and external door applications, including Exitex, Macclex and OUM threshold systems.
Browse our range online or contact our team if you need help identifying the most suitable threshold for your door.
