Choosing the Right Door Latch
A door latch holds a door closed without permanently locking it. When a lever handle or door knob is turned, the latch bolt retracts into the door, allowing the door to open.
Although relatively simple, choosing the correct latch is important. The main factors to consider are the latch type, case length, backset, door furniture, frequency of use and whether the door is fire-rated.
Tubular Door Latches
A tubular latch, sometimes called a tubular mortice latch, is one of the most common choices for internal doors.
The latch mechanism is fitted into a hole drilled into the edge of the door, leaving only the faceplate visible. This provides a neat installation and makes tubular latches suitable for most lever handles and many mortice door knobs.
Tubular latches are available in different lengths, commonly including 2½", 3" and 4" sizes, as well as longer options for particular applications.
What Size Tubular Latch Do I Need?
The length of the latch affects how far the spindle and consequently the door handle or knob sits from the edge of the door.
A 2½" tubular latch is commonly used with lever handles because a lever can generally be operated comfortably relatively close to the edge of the door.
A 3" or 4" latch moves the spindle further away from the door frame. This can be particularly useful with larger mortice door knobs, as additional clearance helps prevent your hand from catching against the frame when turning the knob.
When replacing an existing latch, check both the overall case length and the backset before ordering.
Standard or Heavy-Duty Door Latch?
For normal residential internal doors, a good-quality standard tubular latch will generally provide an appropriate solution.
A heavy-duty door latch may be preferable for frequently used doors or where larger or heavier door furniture is being installed. Heavy-duty bolt-through latches can also provide suitable fixing positions for compatible lever handles, helping the handle fixings pass securely through the door.
The most appropriate option will depend on the door, handles and anticipated level of use.
Door Latches for Fire Doors
If a latch is being installed in a fire-rated door, do not assume that any standard tubular latch is suitable.
Select a product with the appropriate fire-performance documentation or certification for the intended door assembly and follow the manufacturer's installation requirements.
Roundtower Hardware stocks selected fire-rated tubular latches and deadbolts for applications where suitable certified hardware is required.
Rebate Kits for Double Doors
Where two doors close together as a pair, one door may have a rebated edge rather than both doors meeting with square edges.
In these situations, a compatible rebate kit can adapt the latch or lock so that it operates correctly with the rebated door arrangement.
Always ensure that the rebate kit is designed to suit the particular latch or lock being installed.
Frequently Asked Questions
What is a tubular latch?
A tubular latch is a compact latch mechanism morticed into the edge of a door. Turning the door handle or knob retracts the spring-loaded latch bolt, allowing the door to open.
Tubular latches are widely used on internal doors where a locking function is not required.
What size latch do I need for a door handle?
A 2½" or 3" tubular latch is commonly used with lever door handles. The correct size depends on how far you want the handle to sit from the edge of the door and the dimensions of the particular door furniture.
What size latch should I use with a door knob?
A longer latch is often preferable with a mortice door knob because it positions the knob further away from the door frame.
A 3" or 4" latch may therefore provide more comfortable hand clearance than a shorter latch, particularly with larger knobs.
What is the backset on a door latch?
The backset is the distance from the edge of the door to the centre of the spindle that operates the latch.
This measurement is particularly important when replacing an existing latch or selecting a latch to suit particular door handles or knobs.
What is a bolt-through tubular latch?
A bolt-through latch is designed with fixing points that allow compatible door handle bolts to pass through the latch body.
This can provide a secure fixing for bolt-through lever handles and help prevent the handle fixings from interfering with the latch mechanism.
Do I need a fire-rated latch on a fire door?
Where the latch forms part of a fire-rated door assembly, it should be suitable for that application and supported by the appropriate fire-performance documentation.
Always check the requirements of the complete door assembly rather than relying solely on the appearance or size of the latch.
What is a magnetic door latch?
A magnetic latch uses magnetic force to engage the latch as the door closes. This allows the latch bolt to remain less prominent when the door is open and can provide a particularly clean appearance for contemporary doors and ironmongery.
Need Help Choosing a Door Latch?
The correct latch will depend on your door handles or knobs, required backset, door construction and intended use.
Roundtower Hardware supplies a wide selection of tubular door latches, heavy-duty latches, fire-rated latches, magnetic latches and matching door hardware throughout Ireland.
Browse our door latch collection online, or contact our team if you need help matching a latch to your chosen door handles, knobs or existing ironmongery.
