Fire Blocking - help

Hi folks, Still haven't started construction on my project but hopefully soon :roll:. This question has to do with fire blocking - originally I was going to satisfy code by filling the entire cavity between the double walls with fire-rated insulation, but after checking out Rod Gervais' great book I've realized that I can construct a fire block that will let me maintain isolation while saving some money on all that insulation. Here's a cross section of the building, then a detail as to what I'm talking about: Basically I'm wondering if you guys think this would work, or if there might be a simpler way to go. The main difference between what I've got here and the designs in Rod's book (in Chapter 10) is that he has the thermafiber oriented horizontally (usually sandwiched between 1/2" gyp board & the top plate of the inner set of walls). I put the additional piece of 5/8" gyp board there under the thermafiber to make sure it doesn't fall out at some point. Anyway, I'd appreciate any opinions. Thanks! ---Devin

This should be simpler and still work... Steve

Hey Dev, Edit your post and add a space between and so that those two images will break apart (stack) at lower resolution. Otherwise, it's a width of 600 and 700 fused together. --Keith :mrgreen:

Steve, I'm not exactly clear on that picture that you altered.... I take it that there is a slight 'disconnection' between the layers of sheetrock in the fireblock? Otherwise it kinda looks like there is a 'hard' connection... Is that an additional piece of lumber above the sheetrock, or IS that the rock wool? I, too, am interested in fireblock in 'odd' positions... thanx, K

sharward wrote:

Hey Dev, Edit your post and add a space between and so that those two images will break apart (stack) at lower resolution. Otherwise, it's a width of 600 and 700 fused together. --Keith

...edited. Although they stacked up just fine (I'm using Safari) before - maybe it's different in different browsers. Thanks for the tip tho, Keith.

sandman wrote:

. . . they stacked up just fine (I'm using Safari) before - maybe it's different in different browsers.

Ah -- that makes sense. Yes, IE will render two images without a space between them as fused together. It's much better now. 8)

The two layers of gypsum, when viewed from the top, would be slightly notched out around any studs in the OUTER frame so no hard contact; it's OK if the mineral wool is in contact, this way the gypsum will be your main fire block and will support the MW. HTH... Steve