I just took a quick look at some of standards and regulations governing door undercut which is the distance between a door and finished floor as opposed to clearance which is door to sub floor.
Door hardware height off floor.
Door hardware ada compliant locks exit devices handles pulls latches and other operable parts on doors shall comply operable parts of such hardware shall be 34 inches minimum and 48 inches maximum above the finish floor or ground.
Operable parts shall be operable with one hand and shall not require tight grasping pinching or twisting of the wrist.
The international building code has established doorknob height between 34 and 48 inches above a finished floor.
Interior door height off floor.
Figure 2 floor relative to entry door.
Hardware required for accessible door passage shall be mounted no higher than 48 in 1220 mm above finished floor the standard did not define the low limit of the hardware mounting height.
On the inside of the entry door finished flooring is laid on the concrete or wood sub.
Mounting height of hardware.
Installers typically drill the hole centered 36 inches above the floor if not specifically instructed to do so differently exceptions to the rule include doors that provide egress into swimming pools or other water features.
The height of common doors is 6 feet 8 inches.
In the previous edition of the ada standard section 4 13 9 included this statement.
The awi gives no minimum but a maximum of over 3 4 is unacceptable.
It only required a mounting.
The standard height of the rough opening for a door is the door height plus 2 5 8 inches.
Most entry door frames have a piece of lumber below the door and combined with the metal threshold will raise the base of the door off the concrete or wood sub floor by approximately 1 1 4 inches as shown in figure 2.
Door handles pulls latches locks and other operating devices shall be installed 34 inches 864 mm minimum and 48 inches 1219 mm maximum above the finished floor.
Locks used only for security purposes and not used for normal operation are permitted at any height.
Door handles pulls latches locks and other operating devices shall be installed 34 inches 864 mm minimum and 48 inches 1219 mm maximum above the finished floor.