• Welcome to the new and improved Building Code Forum. We appreciate you being here and hope that you are getting the information that you need concerning all codes of the building trades. This is a free forum to the public due to the generosity of the Sawhorses, Corporate Supporters and Supporters who have upgraded their accounts. If you would like to have improved access to the forum please upgrade to Sawhorse by first logging in then clicking here: Upgrades

Minimum ceiling height

4

4thorns

Bronze Member
Joined
Jul 7, 2011
Messages
65
Hi All.
Working with IRC 2012
Please see the code below;

R304.2 Other rooms. Other habitable rooms shall have a floor

area of not less than 70 square feet (6.5 m2).

Exception: Kitchens.

R304.3 Minimum dimensions. Habitable rooms shall not be

less than 7 feet (2134 mm) in any horizontal dimension.

R304.4 Height effect on room area. Portions of a room with a

sloping ceiling measuring less than 5 feet (1524 mm) or a furred

ceiling measuring less than 7 feet (2134 mm) from the finished

floor to the finished ceiling shall not be considered as contributing

to the minimum required habitable area for that room.

R305.1 Minimum height. Habitable space, hallways, bathrooms,

toilet rooms, laundry rooms and portions of basements

containing these spaces shall have a ceiling height of not less

than 7 feet (2134 mm).

1. 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).
________________________________________________________

Does this code mean that the "required floor area" under a Cape style (duel slope) ceiling is the area between the 5' ceilings? For example, if I have 12' between 5' ceiling heights then do I need a minimum of an area 6' wide that has a ceiling height of 7'?

Any help with the exact interpretation of this piece of code would be appreciated.

Thanks,

Doug
 
Rhttp://evstudio.com/how-low-can-you-go-ceiling-heights-in-the-building-code/

Can you link a diagram of what you are asking
 
Doug, you're example would work.

At minimum 7 ft. is required between the 5 ft. ceiling height.

Another example where a steeple type roof line having a ceiling height of 7 ft., one ft. wide and 35 ft. in length with the remainder of the ceiling not less than 5 ft. over 35 ft. of floor will satisfy the 70 sf minimum.
 
Simplifying Francis' explanation, to count towards the 70 sf minimum, 50%, or 35 sf, must be the full 7', the remaining 50%, 35 sf may be between 7' and 5' in height.
 
Thanks for the replies.

So essentially it comes down to the minimum square footage of 70'?

Doug
 
Too much going on here Fatboy. Got that one in before my question. I'm going to take that as a yes. Basically I was trying to figure out if it was that or if the requirement was half the width between the the 5' ceiling heights had to be 7'.

Doug
 
Is it just me or do several parts of the code seem a bit cryptic?
 
"Other habitable rooms shall have a floor

area of not less than 70 square feet"

Required to be 70SF....AS FB said, reductions come off the "required" area.
 
Funny thing is we got rid of "typical projections" in the main house in the 2012 IRC, so now anything below 7' is technically a violation unless you apply the above section ( lights, headers,soffits,etc.) unless they are "sloped".....

R305.1 Minimum height. Habitable space, hallways, bathrooms,
toilet rooms, laundry rooms and portions of basements
containing these spaces shall have a ceiling height of
not less than 7 feet (2134 mm).
Exceptions:
1. 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).
2. Bathrooms shall have a minimum ceiling height of 6
feet 8 inches (2032 mm) at the center of the front
clearance area for fixtures as shown in Figure
R307.1. The ceiling height above fixtures shall be
such that the fixture is capable of being used for its
intended purpose. A shower or tub equipped with a
showerhead shall have a minimum ceiling height of
6 feet 8 inches (2032 mm) above a minimum area 30
inches (762 mm) by 30 inches (762 mm) at the
showerhead.
R305.1.1 Basements. Portions of basements that do not
contain habitable space, hallways, bathrooms, toilet
rooms and laundry rooms shall have a ceiling height of not
less than 6 feet 8 inches (2032 mm).
Exception: Beams, girders, ducts or other obstructions
may project to within 6 feet 4 inches (1931 mm) of the
finished floor.
 
steveray said:
Funny thing is we got rid of "typical projections" in the main house in the 2012 IRC, so now anything below 7' is technically a violation unless you apply the above section ( lights, headers,soffits,etc.) unless they are "sloped".....

That was my question. It used to be that beams bottoms could be 6' 6" if spaced more than 4'0" apart. Now, all I see allowed is the exception in the basement. Does anyone know definitively (and please refer to where in code) it allows the 6'6" beam bottoms ? I am about to design myself into a bad situation, if I can't prove that a 6'8" beam bottom is allowed, still. Thanks! (New to forum)
Click to expand...
 
Just had an email exchange with Douglas Hansen, of Code Check fame. I am SO grateful for those "Code Check" books. He confirmed that it is what it is: 7'0" is the bottom of ceiling, and no other intrusion exceptions. Bummer for my design, but at least I know the deal is the deal. Thanks for all your help!
 
You must log in or register to reply here.
Top