# Fireblock basement soffits



## NE78FJ40 (Feb 7, 2010)

Anyone have any ideas?


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## Gary in WA (Mar 11, 2009)

Page #4: http://www.codecheck.com/cc/images/CC5thEdSample.pdf

16" of compressed unfaced batt insulation in all stud bays facing the ducting soffit, the height of said soffit. Key word---- *INTERSECTIONS. *The top plate of the wall next to the soffit stops fire but the void at soffit/wall stud bay doesn't. Where a vertical wall adjoins a horizontal enclosed space (soffit). I suggest fiber at every 10' along the soffit as well, though not required. If you get a fire in a light housing, it could travel in the floor joist bay to the soffit, to anywhere the other joists go from the soffit. 

Floor/ceiling draft stopped if >1,000sq. ft. & ceiling hung from floor joists.... 502.12 concealed space under stairs and at top and bottom of stringers.... 602.8
Did you read KC's Fireblocking "how to" discussion where you also posted your question at?

Be safe, Gary


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## NE78FJ40 (Feb 7, 2010)

Yes, I've read the whole topic a couple of times.


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## Gary in WA (Mar 11, 2009)

Imagine your drywall on the soffit bottom against the stud wall. Where it butts the wall is where the insulation or other approved fire-blocking needs to be. At the *intersection *of the soffit's ceiling (horizontal) and the wall's vertical joint.

Be safe, Gary


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