Thread: Minimum Interior Door Opening Size

IRC specifies that the main egress door must be 3' wide and 6'8" tall, hinged on one side. But I could not find any minimums regarding interior doors or doors to bathrooms.

16 year old house. Half bath is located under stairway. As a result the stairs intrude into the path of the door way. Dumb design. There is a pantry closet to the right of the bathroom that could be sacraficed to allow the bath to expand so the door could be relocated and would not be blocked by the stairs. Anyway...

Are there any IRC references to the minimun opening size to interior rooms, the size of doorways, or access to bathrooms?

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Originally Posted by Bruce Ramsey

IRC specifies that the main egress door must be 3' wide and 6'8" tall, hinged on one side. But I could not find any minimums regarding interior doors or doors to bathrooms.

16 year old house. Half bath is located under stairway. As a result the stairs intrude into the path of the door way. Dumb design. There is a pantry closet to the right of the bathroom that could be sacraficed to allow the bath to expand so the door could be relocated and would not be blocked by the stairs. Anyway...

Are there any IRC references to the minimun opening size to interior rooms, the size of doorways, or access to bathrooms?

SECTION R305
CEILING HEIGHT
R305.1 Minimum height. Habitable rooms, hallways, corridors,
bathrooms, toilet rooms, laundry rooms and basements
shall have a ceiling height of not less than 7 feet (2134 mm).
The required height shall be measured from the finish floor to
the lowest projection from the ceiling.
Exceptions:
1. Beams and girders spaced not less than 4 feet (1219
mm) on center may project not more than 6 inches
(152 mm) below the required ceiling height.
2. Ceilings in basements without habitable spaces may
project to within 6 feet, 8 inches (2032 mm) of the finished
floor; and beams, girders, ducts or other
obstructions may project to within 6 feet 4 inches
(1931 mm) of the finished floor.
3. For rooms with sloped ceilings, at least 50 percent of
the required floor area of the room must have a ceiling
height of at least 7 feet (2134 mm) and no portion of
the required floor area may have a ceiling height of
less than 5 feet (1524 mm).
4. Bathrooms shall have a minimum ceiling height of 6
feet 8 inches (2036 mm) over the fixture and at the
front clearance area for fixtures as shown in Figure
R307.1. A shower or tub equipped with a showerhead
shall have a minimum ceiling height of 6 feet 8 inches
(2036 mm) above a minimum area 30 inches (762
mm) by 30 inches (762 mm) at the showerhead.
[1]Minimum ceiling heights are required for habitable
rooms hallways, corridors, bathrooms, toilet rooms,
laundry rooms and basements. The minimum required
height of 7 feet (2134 mm) helps maintain a healthy interior
environment. The dimension must be measured
to the lowest projection from the ceiling.
For ceilings having exposed beams that project
down from the ceiling surface, the ceiling beam members
may project no more than 6 inches (152 mm) below
the required ceiling height, provided the beams or
girders are placed at no less than 4 feet (1219 mm) on
center. Basements need have a ceiling height of only 6
feet, 8 inches (2033 mm) or more, with at least 6 feet, 4
inches (1932 mm) of clear height under beams, girders,
ducts and similar obstructions.
For rooms with sloped ceilings, the code requires
only that the prescribed ceiling height be maintained in
one-half the area of the room. However, no portion of
the room that has a ceiling height of less than 5 feet
(1524 mm) must be used in the computations for minimum
floor area.
Exception 4 defines the required minimum ceiling
height over toilet, bath and shower fixtures. This
exception would allow a sloping ceiling over toilet, bath
or shower fixtures if the minimum ceiling height of 6
feet, 8 inches (2036 mm) is maintained over the fixture
and at the front clearance area.

Thanks for the quick response.

In reading through I did not see any specific reference to doorways but there were numerous references to 6'8" and access. Looks like a combination of factors, 50% of floor space, clearance in front of fixture, etc.

I wrote it up as a skull buster.

I wrote it up as a skull buster.

BR: It is definitely that. I always mention the liability issues with such things. Gets the ball rolling quickly.

I don't know of a code that stipulates interior door sizes, minimum or maximum width other than the main entry door, which is an exterior door? However, the common size besides the 6'-8" height; bedroom doors 2'-8" width, random closet 2'-6", and bathrooms 2'-4". You may want to point out that low doors present a hazard to foot traffic, but that would seem fairly obvious to the even less than alert home buyer.
"Your honor, I smacked my head on entering a small closet under the stair and I think I’m entitled to an award because I wasn't told it was below normal height." Judge: "Next case?"

Originally Posted by Bruce Ramsey

I wrote it up as a skull buster.

I called it a "head banger" 'over there'.

Written in ICC parlance:

"The minimum required height of 7 feet (2134 mm) helps maintain a healthy interior environment."

IRC says:

R311.4.2 Door type and size.

The required exit door shall be a side-hinged door not less than 3 feet (914 mm) in width and 6 feet 8 inches (2032 mm) in height. Other doors shall not be required to comply with these minimum dimensions.

I believe that the old BOCA code required a minimum of 2'-6" for all other interior doors and 2'-0" for bathrooms. A BOCA instructor years ago told me that the logic for 2'-0" was that bathrooms usually don't have a lot of people in them, and "if you can get in, then you can get out". I don't know why the 2'-6" is not in IRC. Practically speaking, I don't know why anyone would build a room with a smaller door. It would be tough to get furniture in and out.

IBC has a 32" minimum door width.

1008.1.1 Size of doors.

The minimum width of each door opening shall be sufficient for the occupant load thereof and shall provide a clear width of not less than 32 inches (813 mm).

There are several exceptions to the 32" requirement.

I thought the minimum interior door opening changed to 32" with the Americans with Disabilities Act in the late 80's or early 90's.

Originally Posted by neal lewis

I thought the minimum interior door opening changed to 32" with the Americans with Disabilities Act in the late 80's or early 90's.

NL: Even if, ADA does not apply.