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Determining Type of Construction for permitting

D

Dreamchaser

Registered User
Joined
Apr 23, 2018
Messages
19
Location
Gulf Breeze, FL
This should be simple for the long-timers here!
SFR = Group R-3
House is elevated on concrete pilings / all supporting exterior columns/beams are concrete
All floor systems are steel web trusses
Stairs between floor levels are wood
NO interior load bearing walls
All exterior walls are 12" thick ICF (8" core)
Exterior of exterior walls are covered in 3-coat stucco
All exterior decks are concrete and steel truss with underside covered in treated plywood then covered with stucco
Garage ceiling below is 5/8" type X gyp
Storage enclosure in garage is 5/8" type X gyp (for stair access / elevator)
Interior beams supporting the spans where needed are heavy red steel.
Interior columns supporting the red steel beams are also red steel
All undersides of floors are sprayed with fire-retardant spray foam open cell urethane.
Interior ceilings is planned at 1/2" gyp but could be 5/8" or 5/8" type X if it makes a difference.
Interior walls are 1/2" gyp
Interior walls (all) are insulated with R-13 or R-19 fiberglass batts where appropriate for size
Interior of attic is spray foamed and then covered with radiant barrier
Roof trusses are made of wood, covered with 15/32 decking, covered with peel-n-stick barrier and metal standing seam roof

What is the proposed building classification?
What could it be?
What would make it better/tighter?
Would steel studs in the interior make a difference in classification?
 
CDA - Yes - floors, walls, beams are all concrete (some steel - but not exposed). Garage level as designed has a 3 hour rating, interior of house is required to have 1 hour rating but the floor/ceiling assemblies are all 2+ hour. Interior walls will either be wood stud or metal stud if it makes a difference. Virtually the only combustable materials are the doors, trim, some fixtures, cabinets and furnishings. Floors are all tile.

If this can be classified as a Type IV and with the garage level being a Type I or IV, this fixes the issue from the previous post about the lower level counting as a story. I found a binding determination that lays this out and excludes the parking level as being counted as a story for permitting - making the residence a 3 story.
 
“””What would make it better/tighter?“””

Built entire building out of concrete
 
CDA - actually we were, but the labor to build SCIP is no longer in the area.

Can a residential structure be Class I or II? Most are V, some could be IV, a lot are III. I guess its all about the amount of $$ you want put in materials to reach fire-resistance requirements. Based on what i laid out above, whats missing to get a Type I ?
 
Virtually the only combustable materials are the doors, trim, some fixtures, cabinets and furnishings & ....Roof trusses are made of wood, covered with 15/32 decking, covered with peel-n-stick barrier,
Interior of attic is spray foamed
 
ADAguy - YES! Pretty much all of that. We're in the panhandle of FL. We get bad hurricanes every so often. Fort Walton Beach had 2 or 3 tornadoes last weekend - one was very large (videos on you-tube). We also have Formosan termites pretty bad around here. SO - knowing that the house is going after a number of certifications: LEED Platinum, Gold Key Fortified, EPA WaterSmart, EngeryWise, and NetZero - you can say this is one of a kind. More like "Bullet Proof"....

We've actually found ways to speed up the build process by choosing smarter materials, wise use of materials and new technology to cut about $300,000 off the initial cost and 4 months of build time. "Easy" is not always faster - or cheaper.

For example, on pilings: Lite-Deck system is about 45 days from the day the piles get inspected to go up (assuming weather cooperates). Ecospan Steel Web-truss is 7 days from install to pour to going up to next level. Weight difference is about 100# psf, uses half the concrete and therefore the bearing beams/walls don't have to be as large (more $ saved)
 
my250r11 said:
Virtually the only combustable materials are the doors, trim, some fixtures, cabinets and furnishings & ....Roof trusses are made of wood, covered with 15/32 decking, covered with peel-n-stick barrier,
Interior of attic is spray foamed
Click to expand...
Thanks for the reply - but I am not following your answer. help?
 
OK, going to upset the apple cart here. If the building is a SFR within the parameters of the IRC there is no Type of Construction identified in the IRC. Any materials permitted by the IRC (wood, steel, concrete, etc.) may be used. Why I don't know, but if it is constructed using the IBC Type V-B, sprinklered with a 13R system would permit 4 stories, 60' in height and unlimited area. I go back to my first position, the IRC does not identify any Type of Construction.
 
khsmith55 said:
OK, going to upset the apple cart here. If the building is a SFR within the parameters of the IRC there is no Type of Construction identified in the IRC. Any materials permitted by the IRC (wood, steel, concrete, etc.) may be used. Why I don't know, but if it is constructed using the IBC Type V-B, sprinklered with a 13R system would permit 4 stories, 60' in height and unlimited area. I go back to my first position, the IRC does not identify any Type of Construction.
Click to expand...

NO worries! We are under the Florida Building Code - Building, that does specify in their building code - I think IBC does as well. Even though the IRC covers up to 3 stories, we are 3 stories above a parking area, therefore in theory = 4 stories. The purpose here - in its sole goal, is related to my previous post about whether or not a parking area under a group R-3 counts as a story when the requirement by code and local ordinance is to build elevated. This all comes back to the "story above grade" when it applied specifically to basement, crawl or stem-wall foundations with out any requirements to build elevated on pilings.

FBC-B does not count an S-2 parking level agains the total stories for permitting consideration when built under Group-R. If we can build a SFR (of any type since its not really specified as a type in most cases) over a S-2 garage of Type I enclosed or open or combination thereof, or open of Type IV, then that level is excluded from being a story of the total building because of the separation (3 hour fire). However, the overall height including that level does count against other qualifications or determinations. In our case, we are building new. It was determined by the local BO as a 4 story structure, which then falls outside IRC and the FBC-R. This means threshold design, engineering, structural enhancements, fire sprinklers throughout, and the requirement to have a GC build the house versus a BC. In all, this is a $45K - $55K increase in costs.

IF - big if, we can build a Type I S-2 garage under the residence, then that level does not count as a story for permiting purposes, therefore making the residence back under IRC / FBC-R and 3 stories. No threshold, no sprinklers, no GC costs, etc.

More specifically: (FBC-B)
510.4 Parking beneath Group R.
Where a maximum one-story above grade plane Group S-2 parking garage, enclosed or open, or combination thereof, of Type I construction or open of Type IV construction, with grade entrance, is provided under a building of Group R, the number of stories to be used in determining the minimum type of construction shall be measured from the floor above such a parking area. The number of stories to be used in determining the height in stories in accordance with Section 903.2.11.3 shall include the parking garage as a story. The floor assembly between the parking garage and the Group R above shall comply with the type of construction required for the parking garage and shall also provide a fire-resistance rating not less than the mixed occupancy separation required in Section 508.4.
 
Worked on a SFR outside of Miami way back in 1985 with "blow out" walls at the parking level. As I remember we "bermed" the grade against the "blow out" walls to soften the building mass and elevation so that architecturally it looked like a 2 story house. Could an option like that work for you? I don't know the definition of a "basement" or "below first story" in the FBC but maybe by virtue of raising the grade you could make the parking level a basement with a 3 story dwelling above. Just some random thoughts.
Good luck, Ken
 
Unfortunately this case is somewhat different. We really have 3 stories (finished) above parking. we can only bring in limited fill for pads and parking, but no structural fill. Basements are prohibited in coastal hazard zones. Thanks for the input though!
 
Dreamchaser, saw your other post and have a few questions. You said you can not enclose the parking? This is probably so the storm surge is not impeded. Granted it was over 30 years ago but the South Flordia Building Code permitted the "blow out" walls, I wonder if the code your under has a similar exception. Again just going by memory, the building I worked on was a concrete joist system between concrete beams on concrete columns on concrete pads supported by piles. The blow out walls were unreinforced CMU between the concrete columns, strong enough to retain the backfill (berming) but week enough to "blow out" under a storm surge.
Ken
 
Ken = Correct - storm surge - limited enclosure of blow-out walls is allowed, however its very specific now for a very light hydro-pressure. CMU is not allowed in V-Zones. In some cases, the local ORD prohibits even use of the blow out walls. IN our case, we are in a dual A/V zone on the lot. We have to build to V-zone capacities, but the house being actually in the A-zone, we can use blowout walls if desired. Thats not the issue though. Its getting the FBC rule to allow the parking underneath NOT counting as a story. If we can't, then its a 4 story and threshold determination with the extra costs as mentioned above. If "story above grade" definition was the old one, where it referred specifically to a "Basement" - then we might have some wiggle room. 'Basement" was removed in the current 2017 codes. Its no longer clear. Especially when it comes to a FBC and local ORD to build elevated. Essentially, the code excludes the option to build a 3 story SFR as the FBC-R allows since the lower level can not be enclosed, finished, structural or habitable. (enclosed in this reference means "fully enclosed with permanent walls, windows, doors, etc.
 
Dreamchaser said:
Ken = Correct - storm surge - limited enclosure of blow-out walls is allowed, however its very specific now for a very light hydro-pressure. CMU is not allowed in V-Zones. In some cases, the local ORD prohibits even use of the blow out walls. IN our case, we are in a dual A/V zone on the lot. We have to build to V-zone capacities, but the house being actually in the A-zone, we can use blowout walls if desired. Thats not the issue though. Its getting the FBC rule to allow the parking underneath NOT counting as a story. If we can't, then its a 4 story and threshold determination with the extra costs as mentioned above. If "story above grade" definition was the old one, where it referred specifically to a "Basement" - then we might have some wiggle room. 'Basement" was removed in the current 2017 codes. Its no longer clear. Especially when it comes to a FBC and local ORD to build elevated. Essentially, the code excludes the option to build a 3 story SFR as the FBC-R allows since the lower level can not be enclosed, finished, structural or habitable. (enclosed in this reference means "fully enclosed with permanent walls, windows, doors, etc.
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I wonder if you do not label the area underneath any type of occupancy, but by chance pour concrete that by chance looks like a parking area???

If no use label or occupancy label, maybe it is not a story?? Or whatever they want to call it
 
CDA - tried that already. She (BO) said if it is concrete - then its a floor (finished or not). We even went as far as "gravel" and she said it was a floor.
 
If ICF means insulated concrete forms, the insulation provides a lot of combustibles (as well as termite food) inside the wall. The spray foam may be advertised as fire-retardant, but it will burn. Sounds like type VB construction to me.
 
Paul, Yes ICF is insulated concrete forms. However, ICF does count under Sec 601 for a Type-I material because of the 8" core and rebar. Covered with 1/2 gyp on the interior and stucco (not EFIS) on the outside, the wall has a 4 hour minimum fire-rating at 6" thick core. We are at 8" and exceeds ANSI/UL 263 . Also, Termite food is only cellulose (wood, paper, etc.). The foam in forms could provide a pathway for travel, but not food. The foam used in the ICF has a flame spread of less than 25 = fire resistant. Furthermore, the "spray foam" is open-cell poly-urethane that has flame spread of 21 without the additional retardant added and passed all tests required for NFPA286, NFPA287, ASTM E970, ASTM E 119, its not fire-proof, but is fire resistant. Please remember that to be a Type-I, the structural supporting members must be fire-resistant. Interior can be finished with allowed materials. There are exceptions for the roof structure though allowing a 1.5 hour rating and still being a Type-I depending on the occupancy.
Piles are 14x14 concrete rebar reinforced
Floor systems are steel web-truss under galv pans and 4.5" concrete slab (all floors), protected by the coating and foam
Beams are either 14x20 pre-stressed concrete on exterior/exposed or W8 red steel on the interior and protected
Floors are separated by design with 3-hour ratings
Shaft / walls for elevator and stairs from grade to top floor is 2 hour rated
Interior walls are 1/2"gyp fire-rated X (not that this is needed tho)
interior walls are all NOT load bearing and also are metal studs
No penetrations between floors other than electrical, LV and plumbing.
Roofing has exception for wood truss with fire-retardant treated wood and required fire rating of 1.5 hr - still qualifies as Type-I

So how can this not be at least a Type-IB?
 
Yes they are - but under certain conditions, they are allowed in a Type-I classification building - they need fire-ratings of 1.5 hrs or more. It does make the difference here between A or B though. Thats not the primary question though. And Yes to IBC. IRC got kicked out when the BO said it was a threshold building, even tho its a SFR. So IBC applies.
 
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