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I've got a two-story balloon frame house that is gutted. I have to install fire blocking between studs in the wall cavity. Do I install the fire blocking wherever there is a floor, or wherever there is a ceiling? (Or both?)

Mattzees
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  • I don't deal with any balloon framing in my area but fireblocking isn't structural, it is blocking an air supply. I would tend to think that you would use normal procedures but would like to hear if there are differences from someone more experienced with balloon framing. Probably pics or examples would help too. – DMoore Feb 03 '16 at 21:41
  • Yes, this is why I asked the question. If I install the blocking level with the ceiling of the 1st Floor, it protects the 2nd Floor joists, but if fire came up through a hole in the ceiling, it could eat away at the structure of the 2nd Floor. If I install the fireblock level with the 2nd Floor, it exposes the 2nd Floor structure to flames from below. Very confusing. – Mattzees Feb 03 '16 at 21:45
  • This video gives some suggestions: https://preppernextdoor.wordpress.com/2013/01/01/balloon-construction-fire-blocking/ Also, you might stop by your local firestation and talk with the firefighters. – Yehuda_NYC Feb 03 '16 at 21:57
  • Thank you for that. This one is more comprehensive: https://www.youtube.com/watch?v=dSRpUvSD0l4&feature=player_embedded – Mattzees Feb 03 '16 at 22:38
  • It seems that blocking at the ceiling is what's required. In my area, I have to install X-type (fire-resistant) 5/8" sheetrock on my exterior walls anyway, and so that satisfies the lateral fireblocking requirement. What a pain in the ass. I guess that's why we don't use balloon framing anymore. – Mattzees Feb 03 '16 at 22:41
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    The other reason we stopped using baloon framing is that it became harder to get 20'-long 2x4's... but, yes, fireblocking is an issue. I don't think my inspector checked for that before I bought this pace; guess I should make sure sometime. – keshlam Feb 03 '16 at 23:29

2 Answers2

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Blocking is required wherever a fire or draft can pass from horizontal plane to a vertical plane or vice versa. In otherwords, where the wall meets the floor and the floor meets a ceiling. If fire can pass through one section and travel to another, it needs to be blocked. The 2012 IRC code says that a 16" section of fiberglass insulation will suffice as fireblocking. If you are insulating the outside walls as it is, you will be covered.

Code book page

enter image description here

Jack
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  • If I recall, for fiberglass insulation to be used as fireblocking it has to be unfaced. – Comintern Feb 04 '16 at 04:57
  • That may be so. My memory does not serve me that well all the time, so I will temper what I write next with that. I remember elsewhere in the code, if the insulation is in a confined space, like a stud bay, and not to close off a soffit, the facing is acceptable. I will check to see if I can find it in the exceptions and post it. – Jack Feb 04 '16 at 16:25
  • I found it, see edit – Jack Feb 04 '16 at 16:36
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Whoa...who says you, "have to install X-type (fire resistant) 5/8" sheetrock on my exterior walls anyway, and so that satisfies the lateral fire blocking requirement."

First, Sheetrock on exterior walls is for fire resistance or lateral resistance, not for fire blocking.

Second, sheetrock for fire resistance on exterior walls is ONLY required when your exterior wall needs to be "fire rated". Fire rating for residential construction is ONLY required if the house is constructed too close to the property line...and then only on that one side of the house.

Third, if it's for "lateral resistance", then it must be installed in a certain pattern and nailed properly (correct size and spacing of nails).

Lee Sam
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