# Butler Building - Type II B or Type IV B



## jeffbdesign (Mar 28, 2017)

Project Description:  Convert existing Butler Type warehouse building into business offices and storage
Location: California
Square Footage: New Business office = 2,620 SF
                            Warehouse =  4,580 SF
                                 Total SF = 7,200 SF

Question:  Given the existing building square footage of 7,200 SF can this metal truss, metal roof, concrete floor be classified as Type IV B vs. Type II B?

Reason: The interior "B" business roof would be desired to construct out of wood vs. metal stud.  If classified as Type II the interior wood partitions would need to be FRTW or Type III exterior rated walls.

Confirm: This unprotected metal framed warehouse can be classified as Type V to build interior partitions out of untreated wood.

*Note: The "B" occupancy will need to be separated from the S-2 occupancy with a 2 hour fire rated wall per CBC table 508.4

Thanks


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## cda (Mar 28, 2017)

Welcome!!


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## RLGA (Mar 28, 2017)

Definitely not Type IV, which is limited to heavy-timber construction. You do not indicate if the building is sprinklered or not, but it doesn't really matter based on your building size. Type VB construction for both Group B and S-1 occupancies allows 9,000 sq. ft. of building area. Since your building is less than 9,000 sq. ft., you can Classify it as Type VB construction and as nonseparated uses per Section 508.3.


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## jeffbdesign (Mar 28, 2017)

RLGA said:


> Definitely not Type IV, which is limited to heavy-timber construction. You do not indicate if the building is sprinklered or not, but it doesn't really matter based on your building size. Type VB construction for both Group B and S-1 occupancies allows 9,000 sq. ft. of building area. Since your building is less than 9,000 sq. ft., you can Classify it as Type VB construction and as nonseparated uses per Section 508.3.



Thank you for the response. Great!  I will classify as Type VB. The CBC table 508.4 shows that the separation of occupancies needs to be a 2 hr separation for "B" and S-2 in a non-sprinklered building.  How is it that we can classify it as non separated?  total building SF under 9,000 SF or Chapter 9 provisions.  Want to make sure I have the right language getting the permit passed without a separation.

Thanks


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## RLGA (Mar 28, 2017)

Review Section 508.3. This allows the building to be based on the most restrictive occupancy. Although Groups B and S-1 have the same allowable area, their heights in stories are different. Since Group S-1 is limited to a single story, that will be the most restrictive occupancy since the Group B allows two stories. You only need to separate occupancies when you use the separated uses method per Section 508.4. There's noting that will prevent you from separating the occupancies, but the code allows them to be nonseparated in your situation.


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## cda (Mar 28, 2017)

*jeffbdesign*

*Welcome again!*

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## steveray (Mar 29, 2017)

Just make sure that the owner is aware that "..derating" the building will severely limit future uses and/or additions....My opinion, use steel studs and preserve IIB...


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## ADAguy (Apr 20, 2017)

RL, lets take this a step farther, what if the bldg. describes metal roofing and siding is wearing out and it is a zero lot line building.
1. If I remove and reskin the bldg. (1950's era)  may I only comply with code at time of construction?
2. Can I overskin the existing, leaving the old material in place without having to add seismic reinforcements given the existing structure of tapered beams? It seems that the additional metal skin would add stiffening to the building.
This was brought on by a city maintenance citation.


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