# Draft Stop between floors



## thom (Nov 3, 2006)

The IBC requires draftstopping the mid floor of a two floor building if the upper floor is 1000 square feet or greater. What do you guys use to draftstop open web trusses.


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## homebild (Jun 5, 2005)

*Draftstopping*

1/2" plywood.


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## Tom M (Jan 3, 2007)

IRC Sec R502.12.1 Materials


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## Bob Kovacs (May 4, 2005)

Drywall would be the cheapest/easiest solution, and was accepted last time I checked.

Bob


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## In_Mexifornia (Mar 7, 2007)

I put in draft stops a couple of months ago and I just used 1/2" OSB. At the floor line between the first and second floor and another at the roof line. That's it.


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## thom (Nov 3, 2006)

The IBC allows some "approved alternate materials." I was wondering if sheetmetal would do. My inspector says no so I used sheetrock.

The purpose of the sheetmetal would be it's flexibility in installation. It is used to cover all the open webs of the floor trusses, dividing the mid floor into separate spaces. My feeling was sheetmetal would allow some bending to allow cuts around pipes, ducts, and wires.


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## personalt (Feb 15, 2006)

If you were planning on insulationing anyway you may be able to kill two birds with one stone with Roxual SAFB, sound anntiation(somthing or other) fire batting I think it is called.

only issue is that normally comes about 3 1/2 inches thick. I think it costs me about .30 a square foot so you would be at .60 a square foot it doubling it up fills your joist. if you use drywall you may not have to do every trust but that would requiring further interpertation of the code and discussions with inspector


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## thom (Nov 3, 2006)

This is a draft stop required to divide the mid floor when open web trusses are used so no area is greater than 1000 square feet. Insulation is not an issue.


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## SmithBuilt (Jan 25, 2007)

I'm trying to understand what you are having to draftstop. What is the code reference?


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## Same Old (Mar 9, 2007)

I think he's referring to an enclosed space over 1000 sq ft. It needs to be seperated into spaces less than 1000 ft with a draft stop. 
IRC 502.12

Skinning one truss before it's laid up w/ 1/2 rock works great. (Make sure it's straight)

Without the draftstop flame can spread throughout the house through the open trusses. They put a reasonable limitation on the size of that cavity and also require that the space be divided somewhat evenly.


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## Same Old (Mar 9, 2007)

personalt said:


> If you were planning on insulationing anyway you may be able to kill two birds with one stone with Roxual SAFB, sound anntiation(somthing or other) fire batting I think it is called.
> 
> only issue is that normally comes about 3 1/2 inches thick. I think it costs me about .30 a square foot so you would be at .60 a square foot it doubling it up fills your joist. if you use drywall you may not have to do every trust but that would requiring further interpertation of the code and discussions with inspector


what?


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## Same Old (Mar 9, 2007)

In_Mexifornia said:


> I put in draft stops a couple of months ago and I just used 1/2" OSB. At the floor line between the first and second floor and another at the roof line. That's it.


That's "fireblocking"


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## Tom M (Jan 3, 2007)

Sec 717.3.1 2006 IBC Draftstop materials--- drywall is the cheapest--use scrap out of the dumpster


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