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Seperation of attic from room bellow in bank

TheCommish

TheCommish

SAWHORSE
Joined
Sep 27, 2011
Messages
2,181
Location
Charlton Ma
A proposed type V bank, 2500 square foot, engineer untreated wood truss, on wood frame and portal steel frame walls, with GWB interior walls is being proposed and under plan review.

Question: Using the 2009 IBC and sections bellow, will sheet rock be required on the bottom cord of the roof trusses above the ACT grid and ceiling?

Question does anyone have the 2009 commentary for his section that could share?

717.1 General. Fireblocking and draftstopping shall be installed in combustible concealed locations in accordance with this section. Fireblocking shall comply with Section 717.2. Draftstopping in floor/ceiling spaces and attic spaces shall comply with Sections 717.3 and 717.4, respectively. The permitted use of combustible materials in concealed spaces of buildings of Type I or II construction shall be limited to the applications indicated in Section 717.5.

717.2 Fireblocking. In combustible construction, fireblocking shall be installed to cut off concealed draft openings (both vertical and horizontal) and shall form an effective barrier between floors, between a top story and a roof or attic space. Fireblocking shall be installed in the locations specified in Sections 717.2.2 through 717.2.7.

As always thanks for the help in the confusion.
 
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How are they insulating the roof? I don't think the code allows batts to lay on the ACT

Check the truss details, the bottom chords will need somethin for bracing drywall or 1X's
 
+

Commish,

They will not be permitted to install thermal insulation on the "drop ceiling",

as an effective draft stopping material.

From the `09 IBC, Section 1301.1.1: Criteria. Buildings shall be designed and

constructed in accordance with the International Energy Conservation Code.



From the `09 IECC: Section 502.4.3: Sealing of the building envelope.

Openings and penetrations in the building envelope shall be sealed with caulking

materials or closed with gasketing systems compatible with the construction

materials and location. Joints and seams shall be sealed in the same manner or

taped or covered with a moisture vapor-permeable wrapping material....Sealing

materials spanning joints between construction materials shall allow for expansion

and contraction of the construction materials.

From the `09 IBC, Section 719.1 General: Insulating materials, including facings

such as vapor retarders and vapor-permeable membranes, similar coverings and all

layers of single and multilayer reflective foil insulations, shall comply with the

requirements of this section........Where a flame spread index or a smoke-developed

index is specified in this section, such index shall be determined in accordance with

ASTM E 84 or UL 723.......Any material that is subject to an increase in flame

spread index or smoke-developed index beyond the limits herein established through

the effects of age, moisture or other atmospheric conditions shall not be permitted.

Exceptions:

1. Fiberboard insulation shall comply with :Next('./icod_ibc_2009_23_sec001.htm')'>Chapter 23.

2. Foam plastic insulation shall comply with :Next('./icod_ibc_2009_26_sec001.htm')'>Chapter 26.

3. Duct and pipe insulation and duct and pipe coverings and linings in plenums

shall comply with the International Mechanical Code.

4. All layers of single and multilayer reflective plastic core insulation shall comply

with :Next('./icod_ibc_2009_26_sec013.htm')'>Section 2613.

From the ASHRAE 90.1, `07 Edition, Section 5.8.1.8: The roof insulation shall not

be installed on a suspended ceiling with removable panels.

If you're applying the Energy Conservation requirements, it has to be either the

IECC or the ASHRAE 90.1, but not both!.......Your AHJ would have to formally

adopt the ASHRAE 90.1 standard to replace the IECC.



+
 
The insulation is proposed to be fiberglass laid in on top of vapor barrier the will be attached and sealed to the bottom cord of the trusses in addition supported by 1x3 wood strapping attached to the bottom of the trusses

View attachment 1319 hopfull this is the drawing that you can read
 
Last edited by a moderator:
TheCommish said:
A proposed type V bank, 2500 square foot, engineer untreated wood truss, on wood frame and portal steel frame walls, with GWB interior walls is being proposed and under plan review.Question: Using the 2009 IBC and sections bellow, will sheet rock be required on the bottom cord of the roof trusses above the ACT grid and ceiling?

Question does anyone have the 2009 commentary for his section that could share?

717.1 General. Fireblocking and draftstopping shall be installed in combustible concealed locations in accordance with this section. Fireblocking shall comply with Section 717.2. Draftstopping in floor/ceiling spaces and attic spaces shall comply with Sections 717.3 and 717.4, respectively. The permitted use of combustible materials in concealed spaces of buildings of Type I or II construction shall be limited to the applications indicated in Section 717.5.

717.2 Fireblocking. In combustible construction, fireblocking shall be installed to cut off concealed draft openings (both vertical and horizontal) and shall form an effective barrier between floors, between a top story and a roof or attic space. Fireblocking shall be installed in the locations specified in Sections 717.2.2 through 717.2.7.

As always thanks for the help in the confusion.
Click to expand...
Fireblocking and draftstopping seem off-point.

VA or VB construction? If VB then gypsum is not required. On to the insulation...

2009 IBC

719.3 Exposed installation. Insulating materials, where exposed as installed in buildings of any type of construction, shall have a flame spread index of not more than 25 and a smoke-developed index of not more than 450.

But wait....the insulation is covered by a 'vapor barrier' and is not exposed. What type of vapor barrier? What is its flame spread and smoke-developed index?
 
imhotep & mtlogcabin have it. The insulation will have to have a foil-faced vapor barrier with flame-spread not exceeding 25. A poly vapor barrier doesn't comply. The 1x3 strapping should provide adequate lateral bracing if it is perpendicular to the trusses.

The double top plate provides the necessary fireblocking since the section shows the gyp. board extending all the way up to it. Draftstopping is only required when the attic area is over 3000 SF.
 
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