# Two Different Types of Construction Within One Building



## Mule (Dec 2, 2011)

Okay.... Something I really haven't thought about!

2009 IBC 35,000 sq. ft. of F-1 classification no manufacturing just assembly of components shipped from outside source, 6,000 sq. ft. of B classification. Fully sprinkled. Architect is classifying F-1 area as Type IIA. The offices are being classified as Type VB.

Going to Table 508.4 no separation requirements are required between the two occupancies. Now this is what is throwing me. Two different types of construction under one roof? How can you have two different construction classifications under one roof?

If you classify the F-1 as a IIA wouldn't the rest of the building need to be Type IIA construction unless there is an area separation wall between the two?

My brain is hurting!!!! Am I correct in my thoughts?????? It just don't seem right!!!

Please help!


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## gbhammer (Dec 2, 2011)

Walmart submitted a building made with IIB materials, and for all intent and purpose it was a IIB building, they however listed the construction type as VB (any materials allowed by this code) becuase they could. The BVD was less for VB than it was for IIB.


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## Mule (Dec 2, 2011)

Yeah, BUT they listed it as Type VB didn't they? On mine they specifically stated that there were two different construction types.

I don't know if they can get the amount of square feet with VB!


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## iggentleman (Dec 2, 2011)

I think the architect doesn't understand how the code works.

Unless they have a fire walls or fire separations, it is all one construction type.

Being sprinklered (and I assume one story), it will still be IIA, mixed use non-separated.

I'd get the architect to fix the code analysis, otherwise you could be seen as giving him permission to do an unprotected wood frame within a non-combustible, protected building.

I've sometimes gone the other way, putting on my code analysis VB based on table 503, even though the actual construction might be IIB or IIIB. Couple of times I had the building reviewers insist that I can't do that unless we are building the structure out of wood, but most other reviewers (and their bosses) agree that table 503 sets out the minimum requirements for construction types and not an absolute mandate and "any material permitted by this code" is fine.


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## permitguy (Dec 2, 2011)

> How can you have two different construction classifications under one roof?


A firewall creating separate buildings.  That's the only way.  Don't over-think it.

Does the building meet the requirements to be an unlimited area building?  That may help the designer since they're already putting in sprinklers.  The whole thing could be II-B and avoid rated assemblies.



> Couple of times I had the building reviewers insist that I can't do that unless we are building the structure out of wood


That's got to be infuriating.  A plan reviewer who says a building constructed from non-combustible materials can't be V-B doesn't belong in their position.


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## iggentleman (Dec 2, 2011)

permitguy said:
			
		

> Does the building meet the requirements to be an unlimited area building?  That may help the designer since they're already putting in sprinklers.  The whole thing could be II-B and avoid rated assemblies.


That would be my approach, if a public way is available.



			
				permitguy said:
			
		

> ....That's got to be infuriating.  A plan reviewer who says a building constructed from non-combustible materials can't be V-B doesn't belong in their position.


It was more amusing than frustrating. Both times I got the department head over for a little talk with the reviewer.


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## rooster (Dec 2, 2011)

Mule said:
			
		

> Okay.... Something I really haven't thought about! 2009 IBC 35,000 sq. ft. of F-1 classification no manufacturing just assembly of components shipped from outside source, 6,000 sq. ft. of B classification. Fully sprinkled. Architect is classifying F-1 area as Type IIA. The offices are being classified as Type VB.
> 
> *Going to Table 508.4 no separation requirements are required between the two occupancies. Now this is what is throwing me. Two different types of construction under one roof? How can you have two different construction classifications under one roof?*
> 
> ...


I agree with all other posters.  Take table 508.4 out of the equation...it's not meant to separate contruction types.  It's meant to separate occupancies.


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## Mule (Dec 2, 2011)

Everybody has comfirmed my feelings/thoughts.

Rooster you have to use Table 508.4 to determine IF any separation is required between occupancies and if required then that would determine what type of construction would be required between the two. Now that I have determined that there is not any separation required between occupancies..... I can throw it out!

Thanks folks!!!


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## rooster (Dec 2, 2011)

Mule said:
			
		

> Everybody has comfirmed my feelings/thoughts.Rooster you have to use Table 508.4 to determine IF any separation is required between occupancies and if required then that would determine what type of construction would be required between the two. *Now that I have determined that there is not any separation required between occupancies..... I can throw it out!*
> 
> Thanks folks!!!


I'm confused.  How does this help in your determination of construction types?  I'm not clear on what you've decided.

And Table 508.4 doesn't help you determine type of construction.


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## Papio Bldg Dept (Dec 2, 2011)

gbhammer said:
			
		

> Walmart submitted a building made with IIB materials, and for all intent and purpose it was a IIB building, they however listed the construction type as VB (any materials allowed by this code) becuase they could. The BVD was less for VB than it was for IIB.


I have seen this done specifically to reduce Plan Review and Building Permit fee costs in AHJ's that use the ICC model (I am assuming that is what you are referring to with "BVD").  Has little effect on the valuation of the building as far as I can tell.


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## Mule (Dec 2, 2011)

rooster said:
			
		

> I'm confused.  How does this help in your determination of construction types?  I'm not clear on what you've decided.  And Table 508.4 doesn't help you determine type of construction.


It doesn't help on determining construction types but it does tell me if I need an area separation wall and what rating the wall has to be.

I have determined that the building is going to be a Type IIA. Within that building they cannot have any combustionable materials (Type V). If they want to leave the wood construction then they will have too construct an area separation wall.

If they want to classify the building as Type VB then they are going to have to provide me with the necessary information on area increases etc.


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## Papio Bldg Dept (Dec 2, 2011)

Mule said:
			
		

> If you classify the F-1 as a IIA wouldn't the rest of the building need to be Type IIA construction unless there is an area separation wall between the two?
> 
> Please help!


While your F-1 and B occupancies may not require any separation, your IIA and VB construction types must be limited to one construction type for the whole building (unless as others have noted, these parts are separated into two buildings with a fire wall).  In this case, if the occupancies are not separated and the B occupancy area is built out of VB construction (not just called VB for the sake of it), then the entire building construction type is now VB, and therefore limited in area as described in 504, 506 & 507.


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## AegisFPE (Dec 2, 2011)

The plan review comment may be from Section 602.1, "Buildings... shall be classified in *one* of the five construction types..." (emphasis added)


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## north star (Dec 2, 2011)

** * * **

Send a comment letter / e-mail to the RDP for clarity.

Don't give them design direction. ...Simply request

clarity because of the conflicting code sections and

see what they come back with.

That said, I have, on numerous occasions, had conversations

with various RDP's, to clarify their intended design of the

project.......Sometimes, the actual RDP "of record" is not

the one who is actually designing the project, but rather, a

junior associate.

You are on the right path though!....Question, ...question,

...question!

** * * **


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## gbhammer (Dec 2, 2011)

Papio Bldg Dept said:
			
		

> I have seen this done specifically to reduce Plan Review and Building Permit fee costs in AHJ's that use the ICC model (I am assuming that is what you are referring to with "BVD").  Has little effect on the valuation of the building as far as I can tell.


Yep.

They thought they were being real smart, and I have to admit that they're good, at being smart that is.

Kind of like you Papio. "on to something...  "


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## TJacobs (Dec 4, 2011)

permitguy nailed it in post #5...firewalls creating separate buildings is the only way.


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## Examiner (Dec 5, 2011)

Please do not call them "Area Separation Walls" they have to be "Fire Walls" required mixed construction separations.


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## Mule (Dec 6, 2011)

Examiner said:
			
		

> Please do not call them "Area Separation Walls" they have to be "Fire Walls" required mixed construction separations.


Sorry.... old UBC days!


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## Big Mac (Dec 6, 2011)

I gree with TJake and permitguy.  Firewalls required.


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