# Minimum wall height for habitable spaces per code?



## Just Bill (Dec 21, 2008)

IRC code is min of 7', R305.1


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## Bob Mariani (Dec 1, 2008)

This height has to only apply to a percentage of the room. I think 2/3. This allows you to use sloped side walls you commonly see in attic renovations. However a bigger concern is the floor structure. Joists are not sized to be used for loads required for this renovation.


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## TitaniumVT (Nov 27, 2009)

Bill, Bob, thank you both for the great insight. It's very helpful. Interesting to know that the 7' high requirement only applies to a portion of the space. I've seen attic rooms with sloped ceilings and walls that are far less than 7', so what you've explained makes sense. Doing some research on the web last night, another thing I learned is that in many jurisdictions, areas of a room that are less than 5' in height don't count as floor space for tax assessments. 

Oh man, it didn't even dawn on me that the attic joists might not be sufficiently robust to serve as a floor.  That's a really great point. I'll have an engineer verify feasibility before doing anything.


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## Michael Thomas (Jan 27, 2008)

It's R305, "… not less than 7 feet, not more than 50% of the required floor area is permitted to have a sloped ceiling less than 7 feet with no portion of the required floor area less than 5 feet in height."

Some places require more, for example in Chicago it's 7'-6" (  13-64-050).


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## TitaniumVT (Nov 27, 2009)

Thanks Michael. What's the definition of "required" floor area in this context? Does it relate to the minimum size of a room as mandated by the code? 

By the way, I just came across this useful reference. It refers to Minneapolis, but the basis is the national code, so I imagine it's at least somewhat similar for my area. I wonder if these restrictions are specific to attic bedrooms, or if it applies to any habitable rooms?

http://www.ci.minneapolis.mn.us/inspections/docs/R1atticbdrms.pdf


*Ceiling Height *
2006 IRC Section R305: All ceilings must have a minimum height of seven (7) feet including kitchens, baths, hall, closets, etc. For a sloped ceiling, at least 50% of the floor area must have seven (7) foot ceiling height or higher. The floor area is measured from where the ceiling is at least 5 feet high. ​

​*Room Dimensions *​2006 IRC Section R304: Habitable rooms must have a minimum floor area of 70 square feet, except kitchens, baths, closets and other similar rooms. No habitable rooms can be less than seven (7) feet in width, except kitchen. (Baths are not considered habitable rooms).


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