• Welcome to The Building Code Forum

    Your premier resource for building code knowledge.

    This forum remains free to the public thanks to the generous support of our Sawhorse Members and Corporate Sponsors. Their contributions help keep this community thriving and accessible.

    Want enhanced access to expert discussions and exclusive features? Learn more about the benefits here.

    Ready to upgrade? Log in and upgrade now.

Door opening height - does threshold height count in measurement?

Yikes

SAWHORSE
Joined
Nov 2, 2009
Messages
3,958
Location
Southern California
CBC / IBC 1008.1.1 says "The height of door openings shall not be less than 80 inches."

I have door frames that are installed at 6'-8" without the threshold. When the 1/2" threshold gets installed, the clearance between the top of the threshold and the bottom of the door fram head will then be 6'-7 1/2". The owner wants to know: is that a code violation?

In other words, does the CBC/IBC measure the 80" opening height from the adjacent floor, or from the top of the threshold?
 
Yikes said:
CBC / IBC 1008.1.1 says "The height of door openings shall not be less than 80 inches."I have door frames that are installed at 6'-8" without the threshold. When the 1/2" threshold gets installed, the clearance between the top of the threshold and the bottom of the door fram head will then be 6'-7 1/2". The owner wants to know: is that a code violation?

In other words, does the CBC/IBC measure the 80" opening height from the adjacent floor, or from the top of the threshold?
Why does the owner want to know?
 
Rider Rick said:
Why does the owner want to know?
To be honest, I think the owner's also dissatisfied with the quality of the installation, and he's looking for some additonal ammo to tell the contractor to pull out and reset the frames, using code clearances as a partial justification.
 
Yikes said:
To be honest, I think the owner's also dissatisfied with the quality of the installation, and he's looking for some additonal ammo to tell the contractor to pull out and reset the frames, using code clearances as a partial justification.
I would stay out of it.
 
CBC 1008.1.1 Ex.5 allows door openings in dwelling units to be 78 inches in height.

Ex. 6 allows exterior door openings in dwelling units other than the required exit door to be 76 inches in height.

For other occupancies, 80 inches is the minimum, and it says "opening."

That is pretty clear that it means non-obstructed vertical opening.

Supporting that 80 inches is the minimum, not a nominal dimension with tolerances,

we have 1008.1.1.1 that allows specific projections from door closers and stops to be 78 inches minimum above the floor.

This is all 2013 CBC, which I am studying to get ready. It is unfortunate that it is not more specific about thresholds.

Alas, over a 1/2" threshold I would stay out of it.
 
$ ~ ~ $



"The owner wants to know: is that a code violation?........In other words, does the CBC/IBCmeasure the 80" opening height from the adjacent floor, or from the top of the threshold?"
FWIW, IMO, ...technically, it is a violation of the clear opening required dimension[ i.e. - the letter of the code ].

$ ~ ~ $
 
Did someone cut the bottom of the door off? Are these custom doors that are made too short? Are they measuring from the upper door stop to the top of the threshold?

If the door is its original size, then I doubt it is 79 1/2" tall. At any rate, they are grasping at straws.
 
I agree, most of my projects probably have less than 80 inches from the threshold to the head door stop. No one has ever expressed concern about it. I just wondered what the "official" interpretation is.
 
I have a real hard time imagining any code official calling someone out on this issue, if for no other reason than the amount of work it would create for plan reviewers and field inspectors, and to no great purpose. What possible difference could there be in the utility or safety of a door whose clear opening height is 79.5" instead of 80"? An 80" *nominal* height has been the standard in residential construction for decades, and to a lesser extent in commercial work. I believe the code simply adopted that nominal height as the minimum, again, "nominal" being the operative word.
 
Back
Top