Lowest floor counts as a story in a required elevated SFR?

[dreamchaser69]

We are building a 3 story (finished) elevated SFR with parking underneath that is located in a V-zone in the panhandle of FL. Elevation requirements vary, but all new coastal construction has to be BFE +3' in our area. The lot is zoned as AE-9 where the house is being placed, however because its within 200' of the sound, it is required to be built to V-zone requirements. We can not enclose, finish or make habitable areas on the lower level. We were told by the local BO that the house would be considered a Threshold Building and therefore subject to inspections, engineering, fire sprinklers and must be built by a CGC as a CBC can not build threshold buildings in FLA. They are saying this is 4 stories. Per the definition of "Threshold Building", we are under the height requirements and use/occupancy does not apply = so we are fighting the determination of number of stories. Therefore - we need to define story and story above grade. We also need to define Floor. Lowest floor is the first finished elevated floor.
Conditions:
House must be elevated 3' above BFE
Parking area underneath can not be enclosed
Concrete slab can not be structural, reinforced, must be frangible and saw cut between the concrete pilings to allow break-away
No footings, grade beams, spread-foundations or other support may be used for the slab
A portion of the parking area can be enclosed as per R322 for elevator/stairs/minimal storage
Design:
The House as designed will have lowest floor approx 14' above the required elevation
First Finished floor is about 11'6" above finished grade.
Parking area underneath will be 2' above the required BFE
Built on concrete pilings / ecospan floor trusses and 4.5 concrete slab = on all finished floor levels
Exterior walls are 12" ICF
The concern here stems from the definition of Grade Plane and Story Above Grade Plane. We know the defined words very well and have found in some codes, this relates specifically to basements but most others have the word basement removed. The "story above grade" plane refers to the average of 4 points where the grade adjoins the "exterior walls" = basement walls, stem wall, etc. Then further by the 6' and 12' rules. In the situation where the home is elevated, the grade does not adjoin the exterior walls as there are none and no supporting footers or grade beams or spread foundations are used. We don't think that this was written or intended for use in houses that have an elevation requirement and therefore could reduce the max 3 story SFR allowance to only be 2 finished floors (2 stories), or could push an existing home into the threshold condition and require sprinklers.

Now for the fun part. After being told this was a threshold building by the local BO, and therefore required to be built under "building code" and not "residential", we started reaching out to other local BO's. We got different answers from almost all of them. Our county said Threshold, the beach agency said 3 story elevated over parking (not threshold), 2 counties east said the same - not threshold as long as it is not enclosed except as allowed for by R322. 1 county to the west said - get this - "if the elevation is over 7' to first finished floor, the lower level is considered a story" (what would someone do with 7' for parking?)

So in the wise kingdom here, is there any work-around to get / determine that the lower level is exempt from being considered a story? (making the assumption that the house is "required" to be elevated and the lower level can not finished)

[Jerry Peck - Codeman]

We are building a 3 story (finished) elevated SFR with parking underneath that is located in a V-zone in the panhandle of FL. Elevation requirements vary, but all new coastal construction has to be BFE +3' in our area. The lot is zoned as AE-9 ...

AE-9 typically means that the lowest structural element would be 9 feet elevation, and, with the AE-9 being BFE (does not include the +3'), that would make the lowest structural element at an elevation of 12 feet, making the ground level parking area a "story" by definition, which means you are proposing to construct a 4 story building, not a 3 story building.

We were told by the local BO that the house would be considered a Threshold Building and therefore subject to inspections, engineering, fire sprinklers and must be built by a CGC as a CBC can not build threshold buildings in FLA. They are saying this is 4 stories.

The local building official is both correct and incorrect, but the incorrect part does not affect the end result. A CBC can construct a "threshold building", however, a CBC is not permitted to construct a 4 story building, a CBC is limited to 3 stories and less, and that is a 4 story building.

There are several triggers which make it a threshold building, and 4 stories is one of those triggers, and that particular trigger removes a CBC from being allowed to construct it.l

Per the definition of "Threshold Building", ...

First, let's clarify the defintion of a "threshold building":
- From here: (place cursor over link, right click, select 'open in new tab/window') http://www.leg.state.fl.us/Statutes/ind ... 53.71.html (underlining and bold are mine)
- - 553.71 Definitions.—As used in this part, the term:
- - - (12) “Threshold building” means any building which is greater than three stories or 50 feet in height, or which has an assembly occupancy classification as defined in the Florida Building Code which exceeds 5,000 square feet in area and an occupant content of greater than 500 persons.

A CBC could construct a threshold building which meets the "or" part. A CBC is not permitted by their license to construct a 4 story building:
- From here: (place cursor over link, right click, select 'open in new tab/window') http://www.leg.state.fl.us/Statutes/ind ... 9.105.html
- - 489.105 Definitions.—As used in this part:
- - - (3)
- - - - (b) “Building contractor” means a contractor whose services are limited to construction of commercial buildings and single-dwelling or multiple-dwelling residential buildings, which do not exceed three stories in height, and accessory use structures in connection therewith or a contractor whose services are limited to remodeling, repair, or improvement of any size building if the services do not affect the structural members of the building.

... we are under the height requirements and use/occupancy does not apply = so we are fighting the determination of number of stories. Therefore - we need to define story and story above grade. We also need to define Floor.

From the 2017 Florida Building Code, Building (place cursor over link, right click, select 'open in new tab/window') ( https://codes.iccsafe.org/public/docume ... efinitions ): (underlining and bold are mine)
- SECTION 202
- - DEFINITIONS
- - - STORY. That portion of a building included between the upper surface of a floor and the upper surface of the floor or roof next above (see “Basement,” “Building height,” “Grade plane” and “Mezzanine”). A story is measured as the vertical distance from top to top of two successive tiers of beams or finished floor surfaces and, for the topmost story, from the top of the floor finish to the top of the ceiling joists or, where there is not a ceiling, to the top of the roof rafters.
- - - STORY ABOVE GRADE PLANE. Any story having its finished floor surface entirely above grade plane, or in which the finished surface of the floor next above is:
- - - - 1. More than 6 feet (1829 mm) above grade plane; or
- - - - 2. More than 12 feet (3658 mm) above the finished ground level at any point.

Thus, the space below the living part above, which is to be used for parking, meets the definition of "story", and, additionally, meets the definition of "story above grade plane", in fact, it not only meets the lesser height, it meets both of the "or" heights of the latter definition.

So in the wise kingdom here, is there any work-around to get / determine that the lower level is exempt from being considered a story? (making the assumption that the house is "required" to be elevated and the lower level can not finished)

Nope.

What you described is, by definition, a 4 story building.

And a 4 story building needs to be, per licensing requirements and limitations, constructed by a CGC, not a CBC or a CRC, and is, by definition, a threshold building (but that is not the trigger for not allowing a CBC to construct it, the fact that it is a 4 story building does that).

I realize that is not the answer you were looking for, but maybe you can take some solace in the fact that your local building official is not completely correct on all counts either (not that the outcome is affected, though).

[dreamchaser69]

Thanks Jerry (Codeman). You definitely know your stuff. I do appreciate all the links and this will be helpful to many that have not researched like I have. All of this is very familiar for me now.

In your answers above, a few things that I did not lay out fully. In your answers you are correct to a degree but some math based on circumstances was off - not your fault.

We are required to build on pilings, no matter what the grade elevation is in regards to the flood-zone. We are in an AE-9 with a driveway /street grade elevation of 11' BFE. We have to go to 12' BFE, so we only need to add a little fill to get the garage floor at or above the required BFE. Last 2 storms that came in ('05 and '06) had a storm surge of 7' more than the current elevation (about 18') - so we are going up to have the lowest beam at or about 22' BFE. So, parking pad is at 12' BFE, grade will be brought in to level it out. We can not enclose that level since we have to build to V-zone standards. We can't use a stem-wall foundation to gain the height, it has to be pilings.

That being said, an option that might have come up is to permit as a S-2 open garage (we meet the the construction type) which is then allowed as a max single story above grade, but not counted in the stories above - so this design because of separation, would be an S-2 open garage under a Group R 3-story.

the other thing we are exploring is FBC-R322.1.5 and how that affects what the lowest floor is and if this excludes the "level" underneath from being considered a floor. No floor - no story.

This does seem to come down to "Story Above Grade" and this is where it gets everyone. When reading the definition, I have found others that specified "basement". That word was removed in the FBC 2017 codes (or sometime before). We think that this was originally intent on being used for foundations like basements, crawl, stem-wall, etc. Where the grade actually touches the exterior of the foundation walls. with the elevated homes, we don't have exterior walls and a piling does not constitute a wall, therefore the definition really should not apply to a piling home.

I think that starting a revolution on this might be in order. So many of the Superstorm Sandy homes have to be elevated and this puts them in the same boat as what I want to build. They have 3 story homes now, have to elevate in some cases another 12' which makes them a Threshold, etc..... I think I will start a effort to have the definition of story above grade modified to accommodate houses that are "required" to be elevated in some form or fashion. Where the story above grade is calculated as the average of the 4 points (typ) around a house on a basement, slab, crawl, etc. If this number is greater than 6' or over 12' anywhere, then its a Story above grade. In the case of elevated piling homes where its required (not by choice), then a sufficient height for parking underneath and enclosure per R322 should be allowed, so maybe the elevated piling house is no more than 12' from finished grade to underside of lowest beam, or unless otherwise specified by the local code if the height requirement is more than 12'. We have a local ord just east of here where the required elevation is 17 feet above current grade........17 feet.

Thanks again - lets see what happens with the S-2 garage under Group R and if I can get any traction with the exclusion of the lowest floor in R322.1.5 from being considered a floor. Then grade starts with my first enclosed level.

[Jerry Peck - Codeman]

I can see that you have done research into trying to justify what you want/don't want - so I will start there.

We are required to build on pilings, no matter what the grade elevation is in regards to the flood-zone.

And those pilings create a story, by definition (not the part of the pilings which are below grade, but the area between the pilings above grade and under the floor next above). That story is either "above grade" or "below grade", nonetheless, though, it is a "story" ... as you have acknowledged below trying to explain why it is not.

That being said, an option that might have come up is to permit as a S-2 open garage (we meet the the construction type) which is then allowed as a max single story above grade, ...

That is correct - the parking area within the pilings under the occupancy above (it is "one structure" ... with mixed occupancies).

... but not counted in the stories above ...

Not counted in with the same occupancy, but is counted in the number of stories of the structure/building. That appears to be the failure point in your argument.

- so this design because of separation, would be an S-2 open garage under a Group R 3-story.

1 story open garage
+3 story R-3 Dwelling
=4 story structure/building

... the other thing we are exploring is FBC-R322.1.5 and how that affects what the lowest floor is and if this excludes the "level" underneath from being considered a floor. No floor - no story.

From the 2017 FBC-Building (underlining and bold are mine)
- CHAPTER 1
- - SCOPE AND ADMINISTRATION
- - - PART 1—SCOPE AND APPLICATION
- - - - SECTION 101
- - - - - GENERAL
- - - - - - [A]101.1 Title.
- - - - - - - These regulations shall be known as the Florida Building Code, hereinafter referred to as “this code.”
- - - - - - - - [A]101.2 Scope.
- - - - - - - - - The provisions of this code shall apply to the construction, alteration, relocation, enlargement, replacement, repair, equipment, use and occupancy, location, maintenance, removal and demolition of every building or structure or any appurtenances connected or attached to such buildings or structures.
- - - - - - - - - - Exceptions:
- - - - - - - - - - - 1. Detached one- and two-family dwellings and multiple single-family dwellings (townhouses) not more than three stories above grade plane in height with a separate means of egress, and their accessory structures not more than three stories above grade plane in height, shall comply with the Florida Building Code, Residential.
- - - - - - - - - - - 2. Code requirements that address snow loads and earthquake protection are pervasive; they are left in place but shall not be utilized or enforced because Florida has no snow load or earthquake threat.

It was established above that the structure/building is 4 stories.

I will clarify with a "structure" is and what a "building" is, there is a difference:
- From the 2017 FBC-Building/Residential (the definitions apply to both)
- - [A]BUILDING. Any structure used or intended for supporting or sheltering any use or occupancy.
- - [A]STRUCTURE. That which is built or constructed.

This does seem to come down to "Story Above Grade" and this is where it gets everyone. When reading the definition, I have found others that specified "basement". That word was removed in the FBC 2017 codes (or sometime before). We think that this was originally intent on being used for foundations like basements, crawl, stem-wall, etc. Where the grade actually touches the exterior of the foundation walls. with the elevated homes, we don't have exterior walls and a piling does not constitute a wall, therefore the definition really should not apply to a piling home.

Okay, let's go with your thinking about using that definition:
- STORY ABOVE GRADE PLANE. Any story having its finished floor surface entirely above grade plane, or in which the finished surface of the floor next above is:
- - 1.More than 6 feet (1829 mm) above grade plane; or
- - 2.More than 12 feet (3658 mm) above the finished ground level at any point.

You seem to be placing all your bets on red 17 of the roulette wheel, but the ball is not landing there - red 17 is "finish floor" ... and a "dirt floor" is a "floor" (just described it as a "dirt" "floor") ... the "finished" aspect is the top of the "dirt" "floor" after it was graded/raked/swept/whatever action was done and left to serve as the "finished" floor surface.

The second part of that argument is the "or" part of the definition: "or" "in which the finished surface of the floor next above is" - and that "floor next above" meets 1. and 2.

Thanks again - lets see what happens with the S-2 garage under Group R and if I can get any traction with the exclusion of the lowest floor in R322.1.5 from being considered a floor. Then grade starts with my first enclosed level.

First and foremost, R322.1.5 is from the FBC-Residential, which is not applicable.

But, let's dissect R322.1.5 for you - the first thing is to understand what the section is referencing:
- SECTION R 322
- - FLOOD-RESISTANT CONSTRUCTION
- - - R322.1 General.
- - - - Buildings and structures constructed in whole or in part in flood hazard areas, including A or V Zones and Coastal A Zones, as established in Table R301.2(1), and substantial improvement and restoration of substantial damage of buildings and structures in flood hazard areas, shall be designed and constructed in accordance with the provisions contained in this section. Buildings and structures that are located in more than one flood hazard area shall comply with the provisions associated with the most restrictive flood hazard area. Buildings and structures located in whole or in part in identified floodways shall be designed and constructed in accordance with ASCE 24.
- - - R322.1.5 Lowest floor.
- - - - The lowest floor shall be the lowest floor of the lowest enclosed area, including basement, and excluding any unfinished flood-resistant enclosure that is useable solely for vehicle parking, building access or limited storage provided that such enclosure is not built so as to render the building or structure in violation of this section.

That is stating that, in flood areas, the "lowest floor" (excluding those underlined above) is required to be above the height requirement for flood elevation.

That does not in any way state that any "floor" which is below that level is not counted as a "story".

You are wanting to find a way around the requirements to have to use: a) a CGC; b) the FBC-Building (instead of the FBC-Residential), and, in doing so, you are trying to apply non-applicable sections to your wants, and trying to twist code sections which are for one purpose to another purpose (the purpose of R322.1.5 is to keep the lowest floor of the dwelling above flood damage, not to 'not count the floor below that' for number of stories.

Go for it if you want too, but be forewarned that you are fighting a battle which will ... which SHOULD ... result in the building official essentially saying: 'As I have previously explained in detail, you are proposing to construct a 4 story building. A CBC is not permitted to construct buildings over 3 stories. Also, the Florida Building Code, Residential is only applicable to dwellings 3 stories or less in height, and you are proposing to build a 3 story dwelling OVER a 1 story open parking garage, my math says that 3 stories + 1 story = 4 stories'.

It really is that simple.