Fire Resistive Barrier for townhomes

[Robert Skinner]

Need help ASAP.
Anyone know of a requirement for townhome attics having 1/2 inch drywall on the underside of the rafters adjacent to the common walls. See photos.

[Kenton H. Shepard, CMI]

Originally Posted by rskinner

Need help ASAP.
Anyone know of a requirement for townhome attics having 1/2 inch drywall on the underside of the rafters adjacent to the common walls. See photos.

I ran into it at some point when I was a carpenter. Seems to me they wanted to ensure that fire had no access through which it could jump from one unit to the next through the rafter bay above the rake wall. A valid concern.

[Marcel R. Cyr]

Basically what Kenton said, sometimes the relationship between where the fire break wall is and the rafter above are not conducive to each other and is easier to just sheetrock the rafter bays, which makes it easier to seal.

One question;

Why would they use dense glass drywall in lieu of a cheaper regular type X. ??

Just curious.

Marcel
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[Kenton H. Shepard, CMI]

Originally Posted by mcyr

Why would they use dense glass drywall in lieu of a cheaper regular type X. ??

Just curious.

Marcel
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I wondered about type x too, Marcel. I've never heard of dense glass drywall, though. How do you recognize it and what's it usually used for?

[Marcel R. Cyr]

Kenton, in the second picture I can see just a little of the GP insigna and the fiberous yellow paper would indicate to me to be as this link. We use it all the time for exterior sheathing behind brick veneers.

http://www.gp.com/build/product.aspx...4&hierarchy=pc

Hope this helps.

Marcel