The simple 2X4 double wall R40 insulated design described in your most recent issue was very interesting. I have a question about the impact this design would have on the progression of fire within the wall cavity. I understand that fire blocking is used to slow fire progression vertically within a wall cavity and is required if walls are taller than 8 feet tall. This double wall design would allow fire to spread both vertically and horizontally from wall cavity to wall cavity without a physical wood barrier. Is this a code concern?
Edited 11/26/2009 2:54 pm ET by Scott_Broce
Edited 11/26/2009 2:57 pm ET by Scott_Broce