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Threshold heights

Threshold heights

New postby bigdog on Mon Mar 04, 2019 2:44 pm

Hi Jerry

I see a lot of newer impact rated exterior doors with very high thresholds (2-3") that are in my opinion trip hazards. I know the thresholds are high for wind driven water resistance but I have 2 questions on this.

1) The everyday steel insulated doors from big box stores (hey that rhymes) have a threshold about an inch high and are also impact rated and acceptable for the same locations your expensive impact doors with high thresholds are used. How do the two relate?

and

2) I found a reference to 3/4 of an inch being the maximum high for a protrusion from the floor in B1010.1.7. The 2 exceptions that allow higher (up to 7 3/4" really?) don't seem to apply to front doors that should be considered a means of egress. Also how would that apply to a 10 story condo building with 1 front door and just windows? Do I have my building types screwed up?

David
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Re: Threshold heights

New postby Jerry Peck - Codeman on Mon Mar 04, 2019 6:51 pm

David,

bigdog wrote:I see a lot of newer impact rated exterior doors with very high thresholds (2-3") that are in my opinion trip hazards. I know the thresholds are high for wind driven water resistance but I have 2 questions on this.


First, a question:

By "exterior doors" you are referring to sliding glass doors?

I haven't seen side hinged (swinging) doors with thresholds that high.

However, your next statement indicates that you are referring to side hinged doors:

1) The everyday steel insulated doors from big box stores (hey that rhymes) have a threshold about an inch high and are also impact rated and acceptable for the same locations your expensive impact doors with high thresholds are used. How do the two relate?

and

2) I found a reference to 3/4 of an inch being the maximum high for a protrusion from the floor in B1010.1.7. The 2 exceptions that allow higher (up to 7 3/4" really?) don't seem to apply to front doors that should be considered a means of egress. ... Do I have my building types screwed up?


First, for the code reference - that reference is from the FBC-Building, which is for buildings other than one-family, two-family, townhouses, (3 stories and fewer in height) and their accessory structures ... i.e., that includes "non-residential" and "residential" in the building code.

Sooo ... I will presume that you are basically looking at apartments/condos (same thing in the view of the code as code does not address ownership aspects) as apartments and condos are under the FBC-Building (not the FBC-Residential).

From the 2017 FBC-Building: (underlining and bold are mine)
- 1010.1.7 Thresholds.
- - Thresholds at doorways shall not exceed 3/4 inch (19.1 mm) in height above the finished floor or landing for sliding doors serving dwelling units or 1/2 inch (12.7 mm) above the finished floor or landing for other doors. Raised thresholds and floor level changes greater than 1/4 inch (6.4 mm) at doorways shall be beveled with a slope not greater than one unit vertical in two units horizontal (50-percent slope).
- - - Exceptions:
- - - - 1. In occupancy Group R-2 or R-3, threshold heights for sliding and side-hinged exterior doors shall be permitted to be up to 7 3/4 inches (197 mm) in height if all of the following apply:
- - - - - 1.1. The door is not part of the required means of egress.
- - - - - 1.2. The door is not part of an accessible route as required by Chapter 11.

That "above the finished floor or landing" is referring to the floor or landing on BOTH sides of the door - doors are required to have a floor or landing on each side, and the floor or landing on each side should be level with the other floor or landing (some exceptions apply), with the threshold being allowed to be higher than the floor or landing.

The above 1010.1.7 is saying:
- for sliding doors (typically sliding glass doors) serving dwelling units (apartments, condos, etc), the threshold is allowed to be a maximum of 3/4 inch above the "floor or landing" on either side of the sliding door
- for "other doors" (all "other" doors, doors which are not sliding doors), the threshold is allowed to be 1/2 inch above the floor or landing on either side of the "other" door
- and if that threshold and/or floor level change is greater than 1/4 inch (up to the 1/2 inch allowed) - the threshold or floor level change is allowed to be 1/4 inch vertical, then between that 1/4 inch and the maximum 1/2 inch, the threshold of floor level change shall be sloped (beveled) 1/2:1 (1/4 inch rise for 1/2 inch run from the 1/4 inch height to the maximum 1/2 inch height)

The exceptions in 1010.1.7 also apply to dwelling units, but only dwelling units in R-2 or R-3:
- 310.4 Residential Group R-2.
- - Residential Group R-2 occupancies containing sleeping units or more than two dwelling units where the occupants are primarily permanent in nature, including:
- - - Apartment houses
- - - Boarding houses (nontransient) with more than 16 occupants
- - - Congregate living facilities (nontransient) with more than 16 occupants
- - - Convents
- - - Dormitories
- - - Fraternities and sororities
- - - Hotels (nontransient)
- - - Live/work units
- - - Monasteries
- - - Motels (nontransient)
- - - Vacation timeshare properties

- 310.5 Residential Group R-3.
- - Residential Group R-3 occupancies where the occupants are primarily permanent in nature and not classified as Group R-1, R-2, R-4 or I, including:
- - - Buildings that do not contain more than two dwelling units
- - - Boarding houses (nontransient) with 16 or fewer occupants
- - - Boarding houses (transient) with 10 or fewer occupants
- - - Care facilities that provide accommodations for five or fewer persons receiving care
- - - Congregate living facilities (nontransient) with 16 or fewer occupants
- - - Congregate living facilities (transient) with 10 or fewer occupants
- - - Lodging houses with five or fewer guest rooms
- - 310.5.1 Care facilities within a dwelling.
- - - Care facilities for five or fewer persons receiving care that are within a single-family dwelling are permitted to comply with the Florida Building Code, Residential provided an automatic sprinkler system is installed in accordance with Section 903.3.1.3 or Section P2904 of the Florida Building Code, Residential.
- - 310.5.2 Lodging houses.
- - - Owner-occupied lodging houses with five or fewer guest rooms shall be permitted to be constructed in accordance with the Florida Building Code, Residential.

Getting back to the:
- - - Exceptions:
- - - - 1. In occupancy Group R-2 or R-3, threshold heights for sliding and side-hinged exterior doors shall be permitted to be up to 7 3/4 inches (197 mm) in height if all of the following apply:
- - - - - 1.1. The door is not part of the required means of egress.
- - - - - 1.2. The door is not part of an accessible route as required by Chapter 11.

That 7 3/4 inch threshold height is the riser height for a stair. It is for "exterior doors" and is to allow for a 7 3/4 inch step down (7 3/4 inches from the top of the threshold) to the floor or landing on the exterior side.

It is quite poorly worded.

If you are referring to one-family, two-family, townhouses, three stories or less, and their accessory structures ... then you should be in the FBC-Residential.

Addressing this part separately:
Also how would that apply to a 10 story condo building with 1 front door and just windows?


"how would that apply to a 10 story condo building" - the condo building itself, or to the condos in the building?

To the condos themselves, they are dwelling units, so see all the above stuff.

To the condo building itself - it is not a dwelling unit, so anything related to dwelling units would not apply.
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Re: Threshold heights

New postby bigdog on Wed Mar 06, 2019 1:30 pm

Jerry,

I was mainly referring to residential but have gone to the egress (front) door of condos and found excessively high thresholds on newer impact rated doors.

After looking through the FBC residential the only relevant section I could find was R311.3.1 which states a maximum of 1.5 inches on the interior side as the exterior is allowed up to 7 3/4". I also couldn't find anything other than stairs specs to define interior changes of elevation.

Is the front door always considered an "egress" door? And if so would any hinged front door threshold protruding more than 1.5 inches above the finish floor be a violation? as well as a trip hazard.

David
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Re: Threshold heights

New postby Jerry Peck - Codeman on Wed Mar 06, 2019 2:34 pm

bigdog wrote:I was mainly referring to residential but have gone to the egress (front) door of condos and found excessively high thresholds on newer impact rated doors.


"Residential" meaning the FBC-Residential? Or meaning the condo units themselves?

After looking through the FBC residential the only relevant section I could find was R311.3.1 which states a maximum of 1.5 inches on the interior side as the exterior is allowed up to 7 3/4". I also couldn't find anything other than stairs specs to define interior changes of elevation.


Still referring to condo buildings? If so, the FBC-Residential does not apply.

Is the front door always considered an "egress" door?


No. There is no requirement to even have a "front" door. Any side hinged door leading from the interior to the exterior and a public way (or court or yard which leads to a public way) which meets the requirements for an egress door is allowed to be "the" required egress door ("the" ... one is all that is required by the Residential Code, and one is all that is required by the Building Code for dwelling units within a Building Code building.

And if so would any hinged front door threshold protruding more than 1.5 inches above the finish floor be a violation? as well as a trip hazard.


From the FBC-Residential: (does not apply to condo buildings) (underlining is mine)
- R311.1 Means of egress.
- - Dwellings shall be provided with a means of egress in accordance with this section. The means of egress shall provide a continuous and unobstructed path of vertical and horizontal egress travel from all portions of the dwelling to the required egress door without requiring travel through a garage. The required egress door shall open directly into a public way or to a yard or court that opens to a public way.
- R311.2 Egress door.
- - Not less than one egress door shall be provided for each dwelling unit. The egress door shall be side-hinged, and shall provide a clear width of not less than 32 inches (813 mm) where measured between the face of the door and the stop, with the door open 90 degrees (1.57 rad). The clear height of the door opening shall be not less than 78 inches (1981 mm) in height measured from the top of the threshold to the bottom of the stop. Other doors shall not be required to comply with these minimum dimensions. Egress doors shall be readily openable from inside the dwelling without the use of a key or special knowledge or effort.
- - - (Jerry's comment: No double keyed dead bolts - use of a key inside is not allowed.)
- - - Exception: Buildings that are 400 square feet or less and that are intended for use in conjunction with one-and two-family residences are not subject to the door height and width requirements of this code.
- R311.3 Floors and landings at exterior doors.
- - There shall be a landing or floor on each side of each exterior door. The width of each landing shall be not less than the door served. Every landing shall have a dimension of not less than 36 inches (914 mm) measured in the direction of travel. The slope at exterior landings shall not exceed 1/4 unit vertical in 12 units horizontal (2 percent).
- - - Exception: Exterior balconies less than 60 square feet (5.6 m2) and only accessible from a door are permitted to have a landing less than 36 inches (914 mm) measured in the direction of travel.
- - R311.3.1 Floor elevations at the required egress doors.
- - - Landings or finished floors at the required egress door shall be not more than 1 1/2 inches (38 mm) lower than the top of the threshold.
- - - - Exception: The landing or floor on the exterior side shall be not more than 7 3/4 inches (196 mm) below the top of the threshold.
- - - Where exterior landings or floors serving the required egress door are not at grade, they shall be provided with access to grade by means of a ramp in accordance with Section R311.8 or a stairway in accordance with Section R311.7.

~~~~~~~~~~~~~~

From the FBC-Building: (applies to the condo building itself)
- 1010.1 Doors.
- - Means of egress doors shall meet the requirements of this section. Doors serving a means of egress system shall meet the requirements of this section and Section 1022.2. Doors provided for egress purposes in numbers greater than required by this code shall meet the requirements of this section. For accessibility provisions related to doors, refer to the Florida Building Code, Accessibility.
- - Means of egress doors shall be readily distinguishable from the adjacent construction and finishes such that the doors are easily recognizable as doors. Mirrors or similar reflecting materials shall not be used on means of egress doors. Means of egress doors shall not be concealed by curtains, drapes, decorations or similar materials.
- - 1010.1.1 Size of doors.
- - - The required capacity of each door opening shall be sufficient for the occupant load thereof and shall provide a minimum clear width of 32 inches (813 mm). Clear openings of doorways with swinging doors shall be measured between the face of the door and the stop, with the door open 90 degrees (1.57 rad). Where this section requires a minimum clear width of 32 inches (813 mm) and a door opening includes two door leaves without a mullion, one leaf shall provide a clear opening width of 32 inches (813 mm). The maximum width of a swinging door leaf shall be 48 inches (1219 mm) nominal. Means of egress doors in a Group I-2 occupancy used for the movement of beds shall provide a clear width not less than 41 1/2 inches (1054 mm). The height of door openings shall be not less than 80 inches (2032 mm).
- - - - Exceptions:
- - - - - 1. The minimum and maximum width shall not apply to door openings that are not part of the required means of egress in Group R-2 and R-3 occupancies.
- - - - - 2. Door openings to resident sleeping units in Group I-3 occupancies shall have a clear width of not less than 28 inches (711 mm).
- - - - - 3. Door openings to storage closets less than 10 square feet (0.93 m2) in area shall not be limited by the minimum width.
- - - - - 4. Width of door leaves in revolving doors that comply with Section 1010.1.4.1 shall not be limited.
- - - - - 5. Door openings within a dwelling unit or sleeping unit shall be not less than 78 inches (1981 mm) in height.
- - - - - 6. Exterior door openings in dwelling units and sleeping units, other than the required exit door, shall be not less than 76 inches (1930 mm) in height.
- - - - - 7. In other than Group R-1 occupancies, the minimum widths shall not apply to interior egress doors within a dwelling unit or sleeping unit that is not required to be an Accessible unit.
- - - - - 8. Buildings that are 400 square feet (37 m2) or less and that are intended for use in conjunction with one- and two-family residences are not subject to the door height and width requirements of this code.
- - - - - 9. Doors to walk-in freezers and coolers less than 1,000 square feet (93 m2) in area shall have a maximum width of 60 inches (1524 mm).
- - - - - 10. In Group R-1 dwelling units or sleeping units not required to be Accessible units, the minimum width shall not apply to doors for showers or saunas.

- 1010.1.5 Floor elevation.
- - There shall be a floor or landing on each side of a door. Such floor or landing shall be at the same elevation on each side of the door. Landings shall be level except for exterior landings, which are permitted to have a slope not to exceed 0.25 unit vertical in 12 units horizontal (2-percent slope).
- - - Exceptions:
- - - - 1. Doors serving individual dwelling units in Groups R-2 and R-3 where the following apply:
- - - - - 1.1. A door is permitted to open at the top step of an interior flight of stairs, provided the door does not swing over the top step.
- - - - - 1.2. Screen doors and storm doors are permitted to swing over stairs or landings.
- - - - 2. Exterior doors as provided for in Section 1003.5, Exception 1, and Section 1022.2, which are not on an accessible route.
- - - - 3. In Group R-3 occupancies not required to be Accessible units, the landing at an exterior doorway shall be not more than 7 3/4 inches (197 mm) below the top of the threshold, provided the door, other than an exterior storm or screen door, does not swing over the landing.
- - - - 4. Variations in elevation due to differences in finish materials, but not more than 1/2 inch (12.7 mm).
- - - - 5. Reserved.
- - - - 6. Doors serving equipment spaces not required to be accessible in accordance with Chapter 11 and serving an occupant load of five or less shall be permitted to have a landing on one side to be not more than 7 inches (178 mm) above or below the landing on the egress side of the door.
- 1010.1.6 Landings at doors.
- - Landings shall have a width not less than the width of the stairway or the door, whichever is greater. Doors in the fully open position shall not reduce a required dimension by more than 7 inches (178 mm). Where a landing serves an occupant load of 50 or more, doors in any position shall not reduce the landing to less than one-half its required width. Landings shall have a length measured in the direction of travel of not less than 44 inches (1118 mm).
- - - Exception: Landing length in the direction of travel in Groups R-3 and U and within individual units of Group R-2 need not exceed 36 inches (914 mm).
- 1010.1.7 Thresholds.
- - Thresholds at doorways shall not exceed 3/4 inch (19.1 mm) in height above the finished floor or landing for sliding doors serving dwelling units or 1/2 inch (12.7 mm) above the finished floor or landing for other doors. Raised thresholds and floor level changes greater than 1/4 inch (6.4 mm) at doorways shall be beveled with a slope not greater than one unit vertical in two units horizontal (50-percent slope).
- - - Exceptions:
- - - - 1. In occupancy Group R-2 or R-3, threshold heights for sliding and side-hinged exterior doors shall be permitted to be up to 7 3/4 inches (197 mm) in height if all of the following apply:
- - - - - 1.1. The door is not part of the required means of egress.
- - - - - 1.2. The door is not part of an accessible route as required by Chapter 11.

~~~~~~~~~~~~~~~~~~~

From the FBC-Building: (applies to the condos themselves - basically a repeat of the above which applies to the condo building - bold highlights exceptions ... not that there are doors which are egress doors and doors which are not egress doors - for condos, the "front" door to the corridor is almost always "the" required egress door)
- 1010.1 Doors.
- - Means of egress doors shall meet the requirements of this section. Doors serving a means of egress system shall meet the requirements of this section and Section 1022.2. Doors provided for egress purposes in numbers greater than required by this code shall meet the requirements of this section. For accessibility provisions related to doors, refer to the Florida Building Code, Accessibility.
- - Means of egress doors shall be readily distinguishable from the adjacent construction and finishes such that the doors are easily recognizable as doors. Mirrors or similar reflecting materials shall not be used on means of egress doors. Means of egress doors shall not be concealed by curtains, drapes, decorations or similar materials.
- - 1010.1.1 Size of doors.
- - - The required capacity of each door opening shall be sufficient for the occupant load thereof and shall provide a minimum clear width of 32 inches (813 mm). Clear openings of doorways with swinging doors shall be measured between the face of the door and the stop, with the door open 90 degrees (1.57 rad). Where this section requires a minimum clear width of 32 inches (813 mm) and a door opening includes two door leaves without a mullion, one leaf shall provide a clear opening width of 32 inches (813 mm). The maximum width of a swinging door leaf shall be 48 inches (1219 mm) nominal. Means of egress doors in a Group I-2 occupancy used for the movement of beds shall provide a clear width not less than 41 1/2 inches (1054 mm). The height of door openings shall be not less than 80 inches (2032 mm).
- - - - Exceptions:
- - - - - 1. The minimum and maximum width shall not apply to door openings that are not part of the required means of egress in Group R-2 and R-3 occupancies.
- - - - - 2. Door openings to resident sleeping units in Group I-3 occupancies shall have a clear width of not less than 28 inches (711 mm).
- - - - - 3. Door openings to storage closets less than 10 square feet (0.93 m2) in area shall not be limited by the minimum width.
- - - - - 4. Width of door leaves in revolving doors that comply with Section 1010.1.4.1 shall not be limited.
- - - - - 5. Door openings within a dwelling unit or sleeping unit shall be not less than 78 inches (1981 mm) in height.
- - - - - 6. Exterior door openings in dwelling units and sleeping units, other than the required exit door, shall be not less than 76 inches (1930 mm) in height.
- - - - - 7. In other than Group R-1 occupancies, the minimum widths shall not apply to interior egress doors within a dwelling unit or sleeping unit that is not required to be an Accessible unit.
- - - - - 8. Buildings that are 400 square feet (37 m2) or less and that are intended for use in conjunction with one- and two-family residences are not subject to the door height and width requirements of this code.
- - - - - 9. Doors to walk-in freezers and coolers less than 1,000 square feet (93 m2) in area shall have a maximum width of 60 inches (1524 mm).
- - - - - 10. In Group R-1 dwelling units or sleeping units not required to be Accessible units, the minimum width shall not apply to doors for showers or saunas.

- 1010.1.5 Floor elevation.
- - There shall be a floor or landing on each side of a door. Such floor or landing shall be at the same elevation on each side of the door. Landings shall be level except for exterior landings, which are permitted to have a slope not to exceed 0.25 unit vertical in 12 units horizontal (2-percent slope).
- - - Exceptions:
- - - - 1. Doors serving individual dwelling units in Groups R-2 and R-3 where the following apply:
- - - - - 1.1. A door is permitted to open at the top step of an interior flight of stairs, provided the door does not swing over the top step.
- - - - - 1.2. Screen doors and storm doors are permitted to swing over stairs or landings.
- - - - 2. Exterior doors as provided for in Section 1003.5, Exception 1, and Section 1022.2, which are not on an accessible route.
- - - - 3. In Group R-3 occupancies not required to be Accessible units, the landing at an exterior doorway shall be not more than 7 3/4 inches (197 mm) below the top of the threshold, provided the door, other than an exterior storm or screen door, does not swing over the landing.
- - - - 4. Variations in elevation due to differences in finish materials, but not more than 1/2 inch (12.7 mm).
- - - - 5. Reserved.
- - - - 6. Doors serving equipment spaces not required to be accessible in accordance with Chapter 11 and serving an occupant load of five or less shall be permitted to have a landing on one side to be not more than 7 inches (178 mm) above or below the landing on the egress side of the door.
- 1010.1.6 Landings at doors.
- - Landings shall have a width not less than the width of the stairway or the door, whichever is greater. Doors in the fully open position shall not reduce a required dimension by more than 7 inches (178 mm). Where a landing serves an occupant load of 50 or more, doors in any position shall not reduce the landing to less than one-half its required width. Landings shall have a length measured in the direction of travel of not less than 44 inches (1118 mm).
- - - Exception: Landing length in the direction of travel in Groups R-3 and U and within individual units of Group R-2 need not exceed 36 inches (914 mm).
- 1010.1.7 Thresholds.
- - Thresholds at doorways shall not exceed 3/4 inch (19.1 mm) in height above the finished floor or landing for sliding doors serving dwelling units or 1/2 inch (12.7 mm) above the finished floor or landing for other doors. Raised thresholds and floor level changes greater than 1/4 inch (6.4 mm) at doorways shall be beveled with a slope not greater than one unit vertical in two units horizontal (50-percent slope).
- - - Exceptions:
- - - - 1. In occupancy Group R-2 or R-3, threshold heights for sliding and side-hinged exterior doors shall be permitted to be up to 7 3/4 inches (197 mm) in height if all of the following apply:
- - - - - 1.1. The door is not part of the required means of egress.
- - - - - 1.2. The door is not part of an accessible route as required by Chapter 11.

(Hopefully, I underlined and bold the text correctly, my eyes were glazing over by the time I got to the end.)
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