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How to Determine Construction Type of Existing Building

fj80

fj80

Sawhorse
Joined
Jan 18, 2016
Messages
230
Location
Virginia
I've been asked to determine the construction type of an existing building. I know Chapter 6 gives explanations of the types, but I'm not sure how to figure out what an existing building qualifies as. I do not have the original building plans.

It's a two-story brick warehouse. It was built in 1981. Footprint is 100'x110'. Exterior walls are brick. Interior bearing walls are concrete block. Floors are concrete slab, possibly hollow-core precast slabs.

IBC 2015, Maryland

Any thoughts on which construction type it most likely is?
 
So you want to type it under present code??

And not what code it was built to?

what is your guess?
 
cda said:
So you want to type it under present code??

And not what code it was built to?

what is your guess?
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I'm not sure which is more appropriate. The owner is selling the building and the bank wants a letter stating that to the best of the seller's knowledge the existing building meets code. We've been asked to review this for him. I was going to review it under the current code, IBC 2015, figuring that is the more restrictive, and see if it conforms. If not, I could fall back to the original code it was built under.
 
If nonsprinklered, and assuming the occupancy is Group S-1, then it sounds like Type IIB construction, unless you want to go through the process of determining fire resistance of existing construction per IBC Sections 721 and 722, which could move it to Type VA construction. If there is any unprotected structural steel (i.e., columns or beams) supporting the floor or roof, then it definitely is Type IIB construction.

If the building is sprinklered, then it could be considered Type VB construction based on allowable area.
 
UPDATE: The owner just delivered a few of the original structural drawings and a complete set of remodel drawings done in 2002. These remodel drawings list the construction type as 2B, non-separated mixed use.
Use groups are S1 Storage and B Business.
It is not fire sprinklered.
The building is divided into four long bays using 12" wide CMU bearing walls.

Two of the bays have lofts in them built out of standard 2x wood framing that is not fire-protected. Is this code-compliant in a 2B building?
 
ADAguy said:
Is the building a "zero" lot line or set back from property lines, if so, how far?
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One side is 0.9' from property line. Opposite side (the side facing the street) is 10.1' from property line. Other side is set back 85', and opposite side is set back 90.5'.
 
And the side that is only 0.9' from the property line has a neighboring building within a couple feet of the property line, for a little more than half of the length of the building I'm studying.
 
RLGA said:
Nope.
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Also, if Type 2B allows non-bearing interior walls and partitions to have a 0 hour fire-resistance rating, then why would a wood framed loft/mezzanine that's not fire-rated not be allowed? Doesn't the loft qualify as a non-bearing interior wall or partition?
 
Type IIB construction only permits noncombustible materials except as permitted by Section 603. If the wood is not not FRTW, then it is not permitted per Section 603. Furthermore, Section 603 does not mention the use of FRTW for floor systems, thus if the wood just happened to be FRTW, it still would not be acceptable because the loft is a floor and the walls supporting the loft are, thus, loadbearing, which further excludes them.
 
RLGA said:
Type IIB construction only permits noncombustible materials except as permitted by Section 603. If the wood is not not FRTW, then it is not permitted per Section 603. Furthermore, Section 603 does not mention the use of FRTW for floor systems, thus if the wood just happened to be FRTW, it still would not be acceptable because the loft is a floor and the walls supporting the loft are, thus, loadbearing, which further excludes them.
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If I understand this correctly, does this mean that even though, per Table 601, Type 2B building elements have a fire-resistance rating of 0 hours, they still have to be non-combustible materials? That has always confused me. I thought if Table 601 said 0 hours then that means the materials for that category don't have to be fire-rated at all. No?
 
FWIW we have a number of buildings that are 2B but have wood construction within done without permits or documentation.
If haven't done so I suggest contacting the AHJ for the construction type declared in their records or if they will allow you to use the construction type that will work under the current codes.
 
Francis Vineyard said:
FWIW we have a number of buildings that are 2B but have wood construction within done without permits or documentation.
If haven't done so I suggest contacting the AHJ for the construction type declared in their records or if they will allow you to use the construction type that will work under the current codes.
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Sorry, but what is FWIW, and AHJ?
 
fj80 said:
If I understand this correctly, does this mean that even though, per Table 601, Type 2B building elements have a fire-resistance rating of 0 hours, they still have to be non-combustible materials? That has always confused me. I thought if Table 601 said 0 hours then that means the materials for that category don't have to be fire-rated at all. No?
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See Section 602.2.
Noncombustible does not mean fire-resistant. See Chapter 2 for definitions of "Fire Resistance" and "Fire-Resistance Rating," and Section 703.5 for noncombustibility.
 
?! you don't have AHJ's in Virginia (smiling) authority having jurisdiction.
He meant FRTW (fire rated wood)
If loft was installed without permits you have other issues, load rating of loft floor, attachment to exterior walls, etc..
 
ADAguy said:
?! you don't have AHJ's in Virginia (smiling) authority having jurisdiction.
He meant FRTW (fire rated wood)
If loft was installed without permits you have other issues, load rating of loft floor, attachment to exterior walls, etc..
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Oh god, we have too many AHJ's then. Hahaha.
 
IMO, it sounds like it is a IIIB, non-combustible exterior walls, and any materials on interior, IBC 2015 602.3. The building probably wasn't typed correctly when built or remodeled.
 
my250r11 said:
IMO, it sounds like it is a IIIB, non-combustible exterior walls, and any materials on interior, IBC 2015 602.3. The building probably wasn't typed correctly when built or remodeled.
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That's possible, but it will require an analysis of the exterior bearing walls to verify that they are of 2-hour construction--it shouldn't be too difficult, though.
 
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