Continuous Hinges vs Butt Hinges
, by United Doors and Locks, 3 min reading time
Butt hinges carry a door at three points; continuous hinges carry it along the whole edge. Which openings justify the cost difference.
Butt hinges carry a door at three points. A continuous hinge carries it along the entire edge. Everything else about the comparison follows from that, including the reason continuous hinges cost more up front and less over a building's life.
How the load is distributed
A standard 7-foot door on three butt hinges puts its whole weight through three short sections of the edge. Each hinge sees a share of the dead load plus the leverage created by the door's width, and the top hinge takes the worst of it. Over years of use, that concentration is what produces the familiar failure: the top hinge develops play, the door drops at the latch edge, and the latch stops meeting the strike.
A continuous hinge runs the full height of the door. The same weight is spread along 80-odd inches of edge instead of three points, so no single location is loaded hard enough to wear. A geared continuous hinge such as the FMHD full mortise continuous gear hinge is typically rated for well over two million cycles, and the failure mode that dominates butt hinge service calls essentially disappears.
Where continuous hinges earn their cost
The price difference is real, so the case has to be made per opening rather than across a whole building.
- High-frequency doors. School and hospital corridors, retail entrances, restrooms in public buildings. Anything past roughly 300 cycles a day.
- Heavy or oversized doors. Lead-lined, acoustic, and wide doors that overload butt hinges regardless of their grade.
- Doors that have already failed once. If an opening is on its second or third set of butt hinges, the hinges are not the problem — the point loading is. Continuous is the fix.
- Abuse-prone openings. A continuous hinge closes the gap along the full hinge edge, which removes the purchase a pry bar needs and stops fingers reaching into the gap.
Where a door is wide as well as busy, an offset geared hinge such as the FMOHD full mortise offset continuous gear hinge handles the additional leverage.
Where butt hinges remain correct
Most openings in most buildings. Butt hinges are inexpensive, universally stocked, fit standard frame and door preps, and can be replaced by one person in twenty minutes with no specialist tools. For an interior office door at 40 cycles a day, three H4545 ball bearing hinges will outlast the tenancy.
They are also easier to get right. Continuous hinges are cut to door height and handed to the application; butt hinges are a size and a finish.
Installation and retrofit
This is where continuous hinges lose ground. Butt hinges drop into the standard mortises already cut into virtually every commercial door and frame, so replacement is a like-for-like swap.
A full mortise continuous hinge needs a continuous mortise along the full height of both the door and the frame. On new work that is a factory prep and costs nothing extra to specify. On a retrofit it means routing an existing door and frame in place, which takes time and is not always possible on a rated assembly. Where the mortise is impractical, a full surface continuous hinge mounts to the faces of the door and frame instead — less discreet, far easier to fit.
Fire-rated assemblies
Both types are used on rated doors, but the hinge has to be listed for the assembly. Continuous hinges are commonly listed to 3 hours in steel and aluminium geared versions; butt hinges on a rated door must be steel ball bearing. In either case, match the hinge to the door listing rather than to the hinge's own rating in isolation, and never substitute a hinge on a labelled assembly without checking.
Choosing between them
Ask how often the door moves and how much it weighs. Under a few hundred cycles a day at standard weight, butt hinges are the right economic answer and the maintenance burden is negligible. Above that, or on a door that has sagged before, continuous hinges cost more once and stop costing anything.
Send us the openings with weights and traffic and we will mark which ones justify continuous.