Minimum ceiling height in existing habitable space

[Charles L Montgomery]

I have a code question regarding minimum ceiling height in commercial buildings. The plans call out a space to be a lounge area and the metal bar joists come down at 6'-8" at 4'0" o.c. with the gaps in between at 7'-6". The idea is not to cover the ceiling and leave it exposed. I was wondering how to interpret the ceiling height section of 1208.2 in the IBC. I was told that the metal bar joists could be define as beams or girders so then it could project down to 6'-8" and then go back up to 7'-6" in between. I thought the intent of the code was only for portions of the room or space and not the entire room to be below the minimum ceiling height.

 

[mtlogcabin]

Some of the Legacy Codes did not have a minimum ceiling height except for corridors and hallways

2018 IEBC Level I alteration
4. The minimum ceiling height of the newly created habitable and occupiable spaces and corridors shall be 7 feet (2134 mm).

 

[classicT]

I am a bit thrown off by your reference and what you think the code is. IBC 1208.2 refers to attic access not minimum ceiling heights.

Here is the code you should be looking at for Illinois.

1003.2 Ceiling Height
The means of egress shall have a ceiling height of not less than 7 feet 6 inches (2286 mm) above the finished floor.
Exceptions:

1. Sloped ceilings in accordance with Section 1207.2.
2. Ceilings of dwelling units and sleeping units within residential occupancies in accordance with Section 1207.2.
3. Allowable projections in accordance with Section 1003.3.
4. Stair headroom in accordance with Section 1011.3.
5. Door height in accordance with Section 1010.1.1.
6. Ramp headroom in accordance with Section 1012.5.2.
7. The clear height of floor levels in vehicular and pedestrian traffic areas of public and private parking garages in accordance with Section 406.2.2.
8. Areas above and below mezzanine floors in accordance with Section 505.2.

1003.3 Protruding Objects
Protruding objects on circulation paths shall comply with the requirements of Sections 1003.3.1 through 1003.3.4.

1003.3.1 Headroom​

Protruding objects are permitted to extend below the minimum ceiling height required by Section 1003.2 where a minimum headroom of 80 inches (2032 mm) is provided over any circulation paths, including walks, corridors, aisles and passageways. Not more than 50 percent of the ceiling area of a means of egress shall be reduced in height by protruding objects.

Exception: Door closers and stops shall not reduce headroom to less than 78 inches (1981 mm).

A barrier shall be provided where the vertical clearance above a circulation path is less than 80 inches (2032 mm) high above the finished floor. The leading edge of such a barrier shall be located 27 inches (686 mm) maximum above the finished floor.​

 

[mtlogcabin]

2012 IBC
1208.2 Minimum ceiling heights.
Occupiable spaces, habitable spaces and corridors shall have a ceiling height of not less than 7 feet 6 inches (2286 mm). Bathrooms, toilet rooms, kitchens, storage rooms and laundry rooms shall be permitted to have a ceiling height of not less than 7 feet (2134 mm).

It moved to 1207 in the 2018 edition

 

[Charles L Montgomery]

I am a bit thrown off by your reference and what you think the code is. IBC 1208.2 refers to attic access not minimum ceiling heights.

Here is the code you should be looking at for Illinois.

1003.2 Ceiling Height
The means of egress shall have a ceiling height of not less than 7 feet 6 inches (2286 mm) above the finished floor.
Exceptions:

1. Sloped ceilings in accordance with Section 1207.2.
2. Ceilings of dwelling units and sleeping units within residential occupancies in accordance with Section 1207.2.
3. Allowable projections in accordance with Section 1003.3.
4. Stair headroom in accordance with Section 1011.3.
5. Door height in accordance with Section 1010.1.1.
6. Ramp headroom in accordance with Section 1012.5.2.
7. The clear height of floor levels in vehicular and pedestrian traffic areas of public and private parking garages in accordance with Section 406.2.2.
8. Areas above and below mezzanine floors in accordance with Section 505.2.

1003.3 Protruding Objects
Protruding objects on circulation paths shall comply with the requirements of Sections 1003.3.1 through 1003.3.4.

1003.3.1 Headroom​

Protruding objects are permitted to extend below the minimum ceiling height required by Section 1003.2 where a minimum headroom of 80 inches (2032 mm) is provided over any circulation paths, including walks, corridors, aisles and passageways. Not more than 50 percent of the ceiling area of a means of egress shall be reduced in height by protruding objects.​

​

Exception: Door closers and stops shall not reduce headroom to less than 78 inches (1981 mm).​

​

A barrier shall be provided where the vertical clearance above a circulation path is less than 80 inches (2032 mm) high above the finished floor. The leading edge of such a barrier shall be located 27 inches (686 mm) maximum above the finished floor.​

1208.2 Minimum ceiling heights. Occupiable spaces, habitable spaces and corridors shall have a ceiling height of not
less than 7 feet 6 inches (2286 mm). Bathrooms, toilet rooms,
kitchens, storage rooms and laundry rooms shall have a ceiling height of not less than 7 feet (2134 mm).
Exceptions:
1. In one- and two-family dwellings, beams or girders
spaced not less than 4 feet (1219 mm) on center
shall be permitted to project not more than 6 inches
(152 mm) below the required ceiling height.
2. If any room in a building has a sloped ceiling, the
prescribed ceiling height for the room is required in
one-half the area thereof. Any portion of the room
measuring less than 5 feet (1524 mm) from the finished floor to the ceiling shall not be included in any
computation of the minimum area thereof.
3. The height of mezzanines and spaces below mezzanines shall be in accordance with Section 505.1.
4. Corridors contained within a dwelling unit or sleeping unit in a Group R occupancy shall have a ceiling
height of not less than 7 feet (2134 mm).

 

[classicT]

So, as MtLogCabin pointed out, it appears that you a referencing the 2012 IBC; however, from what I found, Illinois is currently on the 2018 IBC, which is what I posted above.

 

[Yikes]

Charles L, in order to give you useful answers on code forums, we generally need to know:

1. The jurisdiction of this project: Is it in Illinois? What city? This is helpful incase the state or local code adoptions have amendments to the applicable code.
2. The code that was applicable to the original construction of the existing commercial space.
3. If you are altering the existing space (you didn't say), then we need the code that is applicable to the proposed alteration.
4. The existing and proposed occupancy. You said existing was commercial. Is it going to remain commercial? Note that "habitable" generally refers to residential ("living")occupancies, whereas "occupiable space" refers to commercial occupancies - see definitions in IBC 202.

In your two posts, you mentioned IBC 1208.2. However, in the 2018 IBC, the section you quoted is 1207.2, not 1208.2. So, we don't know which edition of the IBC you are applying to your building.

 

[Charles L Montgomery]

Charles L, in order to give you useful answers on code forums, we generally need to know:

1. The jurisdiction of this project: Is it in Illinois? What city? This is helpful incase the state or local code adoptions have amendments to the applicable code.
2. The code that was applicable to the original construction of the existing commercial space.
3. If you are altering the existing space (you didn't say), then we need the code that is applicable to the proposed alteration.
4. The existing and proposed occupancy. You said existing was commercial. Is it going to remain commercial? Note that "habitable" generally refers to residential ("living")occupancies, whereas "occupiable space" refers to commercial occupancies - see definitions in IBC 202.

In your two posts, you mentioned IBC 1208.2. However, in the 2018 IBC, the section you quoted is 1207.2, not 1208.2. So, we don't know which edition of the IBC you are applying to your building.

Sorry the 2015 IBC

 

[Yikes]

I have a code question regarding minimum ceiling height in commercial buildings. The plans call out a space to be a lounge area and the metal bar joists come down at 6'-8" at 4'0" o.c. with the gaps in between at 7'-6". The idea is not to cover the ceiling and leave it exposed. I was wondering how to interpret the ceiling height section of 1208.2 in the IBC. I was told that the metal bar joists could be define as beams or girders so then it could project down to 6'-8" and then go back up to 7'-6" in between. I thought the intent of the code was only for portions of the room or space and not the entire room to be below the minimum ceiling height.

I agree. The minimum height in 2015 IBC 1208.2 is 7'-6" but there's an exception #2 for "sloped ceilings". The bar joists for a protrusion that is analogous to a sloped ceiling (hey, if you want to parse words, it probably even has a slight camber on the bottom surface of the bottom chord). Because they are spaced 4' o/c, they take up less than half of the room area, they qualify under exception #2. They further qualify under 1003.3.1, for being able to egress underneath the joists.






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[ICE]

I would not go along with calling the ceiling anything other than a code violation.

 

[mtlogcabin]

The 7' 6" is the ceiling height. It is a ceiling, a floor ceiling or roof ceiling assembly by code and where any smoke detectors or fire suppression system would be mounted

I thought the intent of the code was only for portions of the room or space and not the entire room to be below the minimum ceiling height.

Last I checked 6' 8" = 80 inches so yes bar joists would meet the protruding objects by code definition. However the protruding objects (bar joists) are limited to a maximum 50% of the ceiling area so therefore I do not believe the "space" is code compliant for a "lounge"

1003.3.1 Headroom
Protruding objects are permitted to extend below the minimum ceiling height required by Section 1003.2 where a minimum headroom of 80 inches (2032 mm) is provided over any circulation paths, including walks, corridors, aisles and passageways. Not more than 50 percent of the ceiling area of a means of egress shall be reduced in height by protruding objects.

 

[Paul Sweet]

Is this an existing ceiling? What code was the building built under, or the space originally remodeled under?

If this is a former storage space that is being converted into a lounge (occupiable space) you will have to request a code modification.

 

[mtlogcabin]

you will have to request a code modification.

The code cannot be "modified" to be less stringent than the original code

[A] 104.1 General.
The building official is hereby authorized and directed to enforce the provisions of this code. The building official shall have the authority to render interpretations of this code and to adopt policies and procedures in order to clarify the application of its provisions. Such interpretations, policies and procedures shall be in compliance with the intent and purpose of this code. Such policies and procedures shall not have the effect of waiving requirements specifically provided for in this code.

[A] 113.2 Limitations on authority.
An application for appeal shall be based on a claim that the true intent of this code or the rules legally adopted thereunder have been incorrectly interpreted, the provisions of this code do not fully apply or an equally good or better form of construction is proposed. The board shall not have authority to waive requirements of this code.

 

[steveray]

In CT it can...and does....

(Add) 104.10 Modifications. Modifications, variations, or exemptions from and approval of equivalent or alternative compliance with the requirements of this code shall be in accordance with the provisions of Sections 104.10.1 to 104.10.6, inclusive.

(Add) 104.10.1 State Building Code. Pursuant to subsection (b) of section 29-254 of the Connecticut General Statutes, the State Building Inspector may grant modifications, variations or exemptions from, or approve equivalent or alternative compliance with, the Connecticut State Building Code where strict compliance with the Connecticut State Building Code would entail practical difficulty or unnecessary hardship, or is otherwise adjudged unwarranted, provided the intent of the law shall be observed and public welfare and safety be assured. Any person aggrieved by any decision of the State Building Inspector may appeal to the Codes and Standards Committee not later than 30 days after mailing of the decision.

 

[mtlogcabin]

where strict compliance with the Connecticut State Building Code would entail practical difficulty or unnecessary hardship, or is otherwise adjudged unwarranted, provided the intent of the law shall be observed and public welfare and safety be assured

You would probably have a hard time in court or in front of the News at 5 cameras using that to defend your decision to allow a lower ceiling height than the code prescribes or protruding objects that exceed 50% of the room area in the event a tragedy occurred in that space .

In Montana we have similar language that a Building Official may waive minor code violations that do not impact the life and safety of the general public.

Minimum ceiling heights also are there to provide clearances for emergency personnel (firefighters) when responding to an incident.

 

[Yikes]

Let’s say the joists are 2" wide and are spaced 16" on center. That means that only (2/16=) 12.5% of the ceiling area Is protruding lower than 7’-6".
Under that scenario, how would you cite that as a code violation, or require a modification to the code?

 

[bill1952]

Yeah, I don't see the hazard of the bottom chord of a bar joist at 6'-8" every 4' in an otherwise open to roof deck space. I might feel differently if a ceiling at 7'-6" between them. Certainly not obstructing egress or lowering smoke level. Sounds exactly like what the CT administrative amendments were written for.

 

[Yikes]

Yeah, I don't see the hazard of the bottom chord of a bar joist at 6'-8" every 4' in an otherwise open to roof deck space. I might feel differently if a ceiling at 7'-6" between them. Certainly not obstructing egress or lowering smoke level. Sounds exactly like what the CT administrative amendments were written for.

Would it even require an amendment? If the surface area of the bottom chords is less than 50% of the ceiling area, doesn‘t it already comply with the written code?

 

[ICE]

I have a code question regarding minimum ceiling height in commercial buildings. The plans call out a space to be a lounge area and the metal bar joists come down at 6'-8" at 4'0" o.c. with the gaps in between at 7'-6". The idea is not to cover the ceiling and leave it exposed. I was wondering how to interpret the ceiling height section of 1208.2 in the IBC. I was told that the metal bar joists could be define as beams or girders so then it could project down to 6'-8" and then go back up to 7'-6" in between. I thought the intent of the code was only for portions of the room or space and not the entire room to be below the minimum ceiling height.

So what is the finished surface between the joist? I have encountered that "factory" look in retail establishments but the height has always been much greater than 7'6".

 

[steveray]

The State approves mods here and you can't sue the State without the State's permission.....

 

[my250r11]

I would have them appeal to the State. This will give some clarification on what the State thinks of the situation and it's interpretation. If the State approves it then it is on them if something happens.

 

[Yikes]

I see several people responding with suggestions of appeals or modifications to ordinances, but those would only be required if the existing conditions do not already comply with the written IBC 2015 code.
With the bar joist protrusions at min. 6'-8" high comprising less than 50% of ceiling area, and likely having a small slope (camber or sag) on the bottom chord, what components could you cite as noncompliant with 1003.3.1 or 1208.2?

 

[steveray]

I get it and I am a little torn, mainly because I am not tall and don't care if people that are 6'8" hit their heads....I ASSUME the 50% has to do with smoke banking not necessarily occupant comfort anyway....But I would have a hard time calling a bar joist a slope, as that implies a plane of the ceiling, not a projection from the ceiling....

 

[ICE]

Where in this is the reason to allow joists to be 10" below the minimum ceiling height.

Section 1003.3.1 is dealing with the means of egress and has nothing to do with a lounge ceiling height.
1003.3 Protruding objects. Protruding objects on circulation paths shall comply with the requirements of Sections 1003.3.1 through 1003.3.

1003.3.1 Headroom. Protruding objects are permitted to extend below the minimum ceiling height required by Section 1003.2 where a minimum headroom of 80 inches is provided over any circulation paths, including walks, corridors, aisles and passageways. In other than Group I-2 and Group I-2.1 occupancies, Not more than 50 percent of the ceiling area of a means of egress shall be permitted to be reduced in height by protruding objects.
.

1207.2 Minimum ceiling heights. Occupiable spaces, habitable spaces and corridors shall have a ceiling height of not less than 7 feet 6 inches above the finished floor. Bathrooms, toilet rooms, kitchens, storage rooms and laundry rooms shall have a ceiling height of not less than 7 feet above the finished floor.

Relying to 1207.2 exception #2 is not a possibility
2. If any room in a building has a sloped ceiling, the prescribed ceiling height for the room is required in one-half the area thereof. Any portion of the room measuring less than 5 feet from the finished floor to the ceiling shall not be included in any computation of the minimum area thereof.