The document discusses fire-rated rim board assemblies used in building construction. It explains that building codes require fire-resistant wall and floor/ceiling assemblies in certain buildings to slow the spread of fire. Rim boards and gypsum wallboards are often used to form fire barriers that prevent flames from escaping confined wall or ceiling assemblies. The document provides details on several rim board assembly designs that have achieved specific fire resistance ratings according to testing standards. It includes diagrams of the assembly configurations and specifications for the rim board thicknesses and types of gypsum wallboards required to achieve different fire resistance periods.

1. D A T A F I L E
To slow or prevent the spread of fire, building
codes require fire-resistant or fire-rated assem-
blies in certain locations, occupancies, and
types of buildings. When fire-rated walls and/
or floor/ceiling assemblies are required, a fire
barrier over the walls is typically necessary
to prevent flames from escaping the confine-
ment provided by the wall or ceiling assembly.
The barrier may be in the form of continuous
rim board on top of the wall and parallel with
the floor joists or as continuous rim board
along the top of the wall and perpendicular to
the joists. A fire barrier can also be made by
inserting individual sections of snugly fit rated
material over the wall and between the floor
joists and carefully sealed against fire passage.
This last method is more labor intensive, particularly when wood I-joists or trusses are used to support the floor.
Because the flammability and ignitability of the adhesive used in the rim boards is less than that of the wood, the
adhesive does not melt prior to ignition. The wood itself determines the flammability of the rim boards.
The assemblies diagrammed in this publication are based on char rates of APA Rim Boards as determined by the United
States Forest Service, Forest Products Laboratory in Madison, Wisconsin.(a)
The Rim Boards in this brochure were
subjected to fire tests that met the requirements of ASTM E119 and CAN/ULC S101.
FIRE-RESISTANT RIM BOARD ASSEMBLIES
The rim board assemblies on the following pages will achieve the fire resistances shown.
(a) White, R. H. 2003. Fire Resistance of Engineered Wood Rim Board Products. Research Paper FPL-RP-610. USDA Forest Service, Forest
Products Laboratory. Madison, WI.
Rim Board® is a registered trademark of APA – The Engineered Wood Association.
APARimBoard®
in
Fire-RatedAssemblies
A gypsum wall board provides fire resistance for rim board assembly
(see “RB1,” next page.)
APA Performance-Rated Rim Boards are manufactured and tested
under the requirements of ANSI/APA PRR 410 or APA PRR 401

2. Form No. D350B ■ © 2015 APA – The Engineered Wood Association ■ www.apawood.org 2
Data File: APA Rim Board in Fire-Rated Assemblies
FIRE RESISTANCE R ATED RIM BOARD ASSEMBLY RB1
This fire resistance design is listed in accordance with ASTM E119 and CAN/ULC S101
RB1
RB2
Load
Gypsum board (B)
Rim board (A)
Ceiling and wall ratings
as required by Building Officials
Ceiling membrane (C)
Stud (D)
Rated wall assembly
Gypsum board (B)
Rim board (A)
Ceiling and wall ratings
as required by Building Officials
Ceiling membrane (C)
Stud (E)
Rated wall assembly
Load Load
Load
Gypsum boards (B)
Rim board (A)
Ceiling and wall ratings
as required by Building OfficialsSame as
right-hand
side drawing
Same as
right-hand
side drawing
Same as
right-hand
side drawing
Same as
right-hand
side drawing
Ceiling membrane (C)
Stud (D)
Rated wall assembly
Gypsum boards (B)
Rim board (A)
Ceiling and wall ratings
as required by Building Officials
Ceiling membrane (C)
Stud (E)
Rated wall assembly
Jan. 4, 2013
Fire_Assembly_Bosie_Rim_Board_2013_v4.eps
Jan. 4, 2013
Fire_Assem
Same a
right-ha
side dra
Same a
right-ha
side dra
Same
right-h
side dr
Same
right-h
side dr
END WALL CONFIGURATION BASE ASSEMBLY
Rim Board
Thickness, in.
Rim Board
Protection
Ceiling Membrane
Req. for 1-hr
Ceiling Membrane
Req. for 2-hr
Stud
Size
Stud
Size
A B C C D E
1
Unprotected 1-hour Fire-rated Assembly 2-hour Fire-rated Assembly 2x4 2x4
(1) 1/2" Type X 5/8" Type X 2-hour Fire-rated Assembly 2x4 2x4
(1) 5/8" Type X 5/8" Type X 90-min Fire-rated Assembly 2x4 2x4
(2) 1/2" Type X No Ceiling Required 1-hour Fire-rated Assembly 2x6 2x4
(2) 5/8" Type X No Ceiling Required 5/8" Type X 2x6 2x4
1-1/8
Unprotected 1-hour Fire-rated Assembly 2-hour Fire-rated Assembly 2x4 2x4
(1) 1/2" Type X 5/8" Type X 2-hour Fire-rated Assembly 2x4 2x4
(1) 5/8" Type X 5/8" Type X 90-min Fire-rated Assembly 2x4 2x4
(2) 1/2" Type X No Ceiling Required 1-hour Fire-rated Assembly 2x6 2x4
(2) 5/8" Type X No Ceiling Required 5/8" Type X 2x6 2x4
1-1/4
Unprotected 1-hour Fire-rated Assembly 2-hour Fire-rated Assembly 2x4 2x4
(1) 1/2" Type X 5/8" Type X 2-hour Fire-rated Assembly 2x4 2x4
(1) 5/8" Type X 5/8" Type X 90-min Fire-rated Assembly 2x6 2x4
(2) 1/2" Type X No Ceiling Required 1-hour Fire-rated Assembly 2x6 2x4
(2) 5/8" Type X No Ceiling Required 5/8" Type X 2x6 2x4
1-1/2
Unprotected 1-hour Fire-rated Assembly 2-hour Fire-rated Assembly 2x4 2x4
(1) 1/2" Type X 5/8" Type X 90-min Fire-rated Assembly 2x6 2x4
(1) 5/8" Type X 1/2" Type X 90-min Fire-rated Assembly 2x6 2x4
(2) 1/2" Type X No Ceiling Required 1-hour Fire-rated Assembly 2x6 2x4
(2) 5/8" Type X No Ceiling Required 5/8" Type X 2x6 2x6
1-3/4
Unprotected 1-hour Fire-rated Assembly 2-hour Fire-rated Assembly 2x4 2x4
(1) 1/2" Type X 5/8" Type X 90-min Fire-rated Assembly 2x6 2x4
(1) 5/8" Type X 1/2" Type X 90-min Fire-rated Assembly 2x6 2x4
(2) 1/2" Type X No Ceiling Required 45-min Fire-rated Assembly 2x6 2x6
(2) 5/8" Type X No Ceiling Required 5/8" Type X 2x6 2x6
1) Rim assembly for fire from inside of structure.
2) Gypsum wallboard shown on the ceiling is to protect the rim board only. It does not necessarily cause the floor assembly to be rated.
3) Attach 1-layer Type X (1/2 or 5/8-inch) gypsum wallboard to rim board with 1-1/2-inch Type W drywall screws spaced 12 inches o.c.
4) Attach 2-layer Type X (1/2 or 5/8-inch) gypsum wallboards to rim board with 2-inch Type W drywall screws spaced 12 inches o.c.
5) Provide min. 1-3/4-inch bearing for I-joist.
6) Use only fire-rated gypsum wallboard. Type C may be substituted for Type X.
7) Rim board and gypsum wallboard thicknesses are shown as minimums. Thicker rim board and gypsum wallboard may be substituted.
8) When 2-layer gypsum wallboards are used, I-joist end nails shall be 16d box (0.135 inch x 3-1/2 inches) nails.
9) Rim board needs to be sized for vertical and lateral loads.

3. Form No. D350B ■ © 2015 APA – The Engineered Wood Association ■ www.apawood.org 3
Data File: APA Rim Board in Fire-Rated Assemblies
FIRE RESISTANCE R ATED RIM BOARD ASSEMBLY RB2
This fire resistance design is listed in accordance with ASTM E119 and CAN/ULC S101RB2
Load
Stud (D)
Rated wall assembly
Stud (E)
Rated wall assembly
Load
Gypsum boards (B)
Rim board (A)
Ceiling and wall ratings
as required by Building OfficialsSame as
right-hand
side drawing
Same as
right-hand
side drawing
Same as
right-hand
side drawing
Same as
right-hand
side drawing
Ceiling membrane (C)
Stud (D)
Rated wall assembly
Gypsum boards (B)
Rim board (A)
Ceiling and wall ratings
as required by Building Officials
Ceiling membrane (C)
Stud (E)
Rated wall assembly
Jan. 4, 2013
Fire_Assembly_Bosie_Rim_Board_2013_v4.eps
Jan
Fi
SINGLE WALL CONFIGURATION BASE ASSEMBLY
Rim Board
Thickness, in.
Rim Board
Protection
Ceiling Membrane
Req.for 1-hr
Ceiling Membrane
Req.for 2-hr
Stud
Size
Stud
Size
A B C C D E
1
Unprotected 45-min Fire-rated Assembly 2-hour Fire-rated Assembly 2x6 2x4
(1) 1/2" Type X 1/2" Type X 90-min Fire-rated Assembly 2x6 2x6
(1) 5/8" Type X 1/2" Type X 90-min Fire-rated Assembly 2x8 2x6
(2) 1/2" Type X No Ceiling Required 5/8" Type X 2x8 2x6
(2) 5/8” Type X No Ceiling Required 1/2" Type X 2x8 2x6
1-1/8
Unprotected 45-min Fire-rated Assembly 2-hour Fire-rated Assembly 2x6 2x4
(1) 1/2" Type X 1/2" Type X 90-min Fire-rated Assembly 2x8 2x6
(1) 5/8" Type X 1/2" Type X 90-min Fire-rated Assembly 2x8 2x6
(2) 1/2" Type X No Ceiling Required 5/8" Type X 2x8 2x6
(2) 5/8" Type X No Ceiling Required 1/2" Type X 2x8 2x6
1-1/4
Unprotected 5/8" Type X 2-hour Fire-rated Assembly 2x6 2x4
(1) 1/2" Type X 1/2" Type X 90-min Fire-rated Assembly 2x8 2x6
(1) 5/8" Type X 1/2" Type X 90-min Fire-rated Assembly 2x8 2x6
(2) 1/2" Type X No Ceiling Required 1/2" Type X 2x8 2x6
(2) 5/8" Type X No Ceiling Required 1/2" Type X 2x8 2x6
1-1/2
Unprotected 5/8" Type X 2-hour Fire-rated Assembly 2x6 2x4
(1) 1/2" Type X 1/2" Type X 90-min Fire-rated Assembly 2x8 2x6
(1) 5/8" Type X No Ceiling Required 1-hour Fire-rated Assembly 2x8 2x6
(2) 1/2" Type X No Ceiling Required 1/2" Type X 2x8 2x6
(2) 5/8" Type X No Ceiling Required 1/2" Type X 2x8 2x8
1-3/4
Unprotected 5/8" Type X 90-min Fire-rated Assembly 2x6 2x4
(1) 1/2" Type X 1/2" Type X 90-min Fire-rated Assembly 2x8 2x6
(1) 5/8" Type X No Ceiling Required 1-hour Fire-rated Assembly 2x8 2x6
(2) 1/2" Type X No Ceiling Required 1/2" Type X 2x8 2x6
(2) 5/8" Type X No Ceiling Required No Ceiling Required 2x8 2x8
1) Rim assembly for fire from either side of wall.
2) Gypsum wallboard shown on the ceiling is to protect the rim board only. It does not necessarily cause the floor assembly to be rated.
3) Attach 1-layer Type X (1/2 or 5/8-inch) gypsum wallboard to rim board with 1-1/2-inch Type W drywall screws spaced 12 inches o.c.
4) Attach 2-layer Type X (1/2 or 5/8-inch) gypsum wallboards to rim board with 2-inch Type W drywall screws spaced 12 inches o.c.
5) Provide min. 1-3/4-inch bearing for I-joist.
6) Use only fire-rated gypsum wallboard. Type C may be substituted for Type X.
7) Rim board and gypsum wallboard thicknesses are shown as minimums. Thicker rim board and gypsum wallboard may be substituted.
8) Toenailing from the I-joist flange to the rim is permitted. When 2-layer (or more) gypsum wallboards are used, I-joist end nails shall be 16d
box (0.135 inch x 3-1/2 inches) nails.
9) Rim board needs to be sized for vertical and lateral loads.

4. Form No. D350B ■ © 2015 APA – The Engineered Wood Association ■ www.apawood.org 4
Data File: APA Rim Board in Fire-Rated Assemblies
RB3
RB4
ficials
Load Load
Load Loadngs
ng Officials
C)
Gypsum board (B)
Rim board (A)
Ceiling and wall ratings
as required by Building Officials
Ceiling membrane (C)
Stud (D)
Rated wall assembly
Gypsum board (B)
Rim board (A)
Ceiling and wall ratings
as required by Building Officials
Ceiling membrane (C)
Stud (E)
Rated wall assembly
Gypsum board (B)
Rim board (A)
Ceiling and wall ratings
as required by Building Officials
Ceiling membrane (C)
Stud (D)
Rated wall assembly
Gypsum board (B)
Rim board (A)
Ceiling and wall ratings
as required by Building Officials
Ceiling membrane (C)
Stud (E)
Rated wall assembly
Jan. 4, 2013
Fire_Assembly_Bosie_Rim_Board_2013_v4.eps
Same as
right-hand
side drawing
Same as
right-hand
side drawing
Same as
right-hand
side drawing
Same as
right-hand
side drawing
Same as
right-hand
side drawing
Same as
right-hand
side drawing
Same as
right-hand
side drawing
Same as
right-hand
side drawing
FIRE RESISTANCE R ATED RIM BOARD ASSEMBLY RB3
This fire resistance design is listed in accordance with ASTM E119 and CAN/ULC S101
DOUBLE WALL CONFIGURATION WITH LOAD TRANSFER BASE ASSEMBLY
Rim Board
Thickness, in.
Rim Board
Protection
Ceiling Membrane
Req. for 1-hr
Ceiling Membrane
Req.for 2-hr
Stud
Size
Stud
Size
A B C C D E
1
Unprotected 1/2" Type X 90-min Fire-rated Assembly 2x4 2x4
(1) 1/2" Type X No Ceiling Required 1-hour Fire-rated Assembly 2x4 2x4
(1) 5/8" Type X No Ceiling Required 45-min Fire-rated Assembly 2x6 2x4
(2) 1/2" Type X No Ceiling Required No Ceiling Required 2x6 2x4
(2) 5/8" Type X No Ceiling Required No Ceiling Required 2x6 2x4
1-1/8
Unprotected 1/2" Type X 90-min Fire-rated Assembly 2x4 2x4
(1) 1/2" Type X No Ceiling Required 1-hour Fire-rated Assembly 2x4 2x4
(1) 5/8" Type X No Ceiling Required 5/8" Type X 2x4 2x4
(2) 1/2" Type X No Ceiling Required No Ceiling Required 2x6 2x4
(2) 5/8" Type X No Ceiling Required No Ceiling Required 2x6 2x4
1-1/4
Unprotected 1/2" Type X 90-min Fire-rated Assembly 2x4 2x4
(1) 1/2" Type X No Ceiling Required 45-min Fire-rated Assembly 2x4 2x4
(1) 5/8" Type X No Ceiling Required 5/8" Type X 2x4 2x4
(2) 1/2" Type X No Ceiling Required No Ceiling Required 2x6 2x4
(2) 5/8" Type X No Ceiling Required No Ceiling Required 2x6 2x4
1-1/2
Unprotected No Ceiling Required 1-hour Fire-rated Assembly 2x4 2x4
(1) 1/2" Type X No Ceiling Required 5/8" Type X 2x6 2x4
(1) 5/8" Type X No Ceiling Required 1/2" Type X 2x6 2x4
(2) 1/2" Type X No Ceiling Required No Ceiling Required 2x6 2x4
(2) 5/8" Type X No Ceiling Required No Ceiling Required 2x6 2x6
1-3/4
Unprotected No Ceiling Required 1-hour Fire-rated Assembly 2x6 2x6
(1) 1/2" Type X No Ceiling Required 1/2" Type X 2x6 2x6
(1) 5/8" Type X No Ceiling Required No Ceiling Required 2x6 2x6
(2) 1/2" Type X No Ceiling Required No Ceiling Required 2x6 2x6
(2) 5/8" Type X No Ceiling Required No Ceiling Required 2x6 2x6
1) Rim assembly for fire from either side of wall. “With load transfer” assumes load transfers to the adjacent rim board if the fire exposed rim
board fails.
2) Gypsum wallboard shown on the ceiling is to protect the rim board only. It does not necessarily cause the floor assembly to be rated.
3) Attach 1-layer Type X (1/2 or 5/8-inch) gypsum wallboard to rim board with 1-1/2-inch Type W drywall screws spaced 12 inches o.c.
4) Attach 2-layer Type X (1/2 or 5/8-inch) gypsum wallboards to rim board with 2-inch Type W drywall screws spaced 12 inches o.c.
5) Provide min. 1-3/4-inch bearing for I-joist.
6) Use only fire-rated gypsum wallboard. Type C may be substituted for Type X.
7) Rim board and gypsum wallboard thicknesses are shown as minimums. Thicker rim board and gypsum wallboard may be substituted.
8) Toenailing from the I-joist flange to the rim is permitted. When 2-layer gypsum wallboards are used, I-joist end nails shall be 16d box
(0.135 inch x 3-1/2 inches) nails.
9) Rim board needs to be sized for vertical and lateral loads.

5. Form No. D350B ■ © 2015 APA – The Engineered Wood Association ■ www.apawood.org 5
Data File: APA Rim Board in Fire-Rated Assemblies
RB4
Load Loadgs
ng Officials
C)
Rated wall assembly Rated wall assembly
Gypsum board (B)
Rim board (A)
Ceiling and wall ratings
as required by Building Officials
Ceiling membrane (C)
Stud (D)
Rated wall assembly
Gypsum board (B)
Rim board (A)
Ceiling and wall ratings
as required by Building Officials
Ceiling membrane (C)
Stud (E)
Rated wall assembly
Jan. 4, 2013
Fire_Assembly_Bosie_Rim_Board_2013_v4.eps
side drawing
Same as
right-hand
side drawing
Same as
right-hand
side drawing
Same as
right-hand
side drawing
Same as
right-hand
side drawing
side drawing
FIRE RESISTANCE R ATED RIM BOARD ASSEMBLY RB4
This fire resistance design is listed in accordance with ASTM E119 and CAN/ULC S101
DOUBLE WALL CONFIGURATION WITH LOAD TRANSFER BASE ASSEMBLY
Rim Board
Thickness, in.
Rim Board
Protection
Ceiling Membrane
Req. for 1-hr
Ceiling Membrane
Req. for 2-hr
Stud
Size
Stud
Size
A B C C D E
1
Unprotected 1/2" Type X 90-min Fire-rated Assembly 2x4 2x4
(1) 1/2" Type X No Ceiling Required 1-hour Fire-rated Assembly 2x4 2x4
(1) 5/8" Type X No Ceiling Required 1-hour Fire-rated Assembly 2x4 2x4
(2) 1/2" Type X No Ceiling Required 1/2" Type X 2x6 2x4
(2) 5/8" Type X No Ceiling Required 1/2" Type X 2x6 2x4
1-1/8
Unprotected 1/2" Type X 90-min Fire-rated Assembly 2x4 2x4
(1) 1/2" Type X No Ceiling Required 1-hour Fire-rated Assembly 2x4 2x4
(1) 5/8" Type X No Ceiling Required 1-hour Fire-rated Assembly 2x4 2x4
(2) 1/2" Type X No Ceiling Required 1/2" Type X 2x6 2x4
(2) 5/8" Type X No Ceiling Required No Ceiling Required 2x6 2x4
1-1/4
Unprotected 1/2" Type X 90-min Fire-rated Assembly 2x4 2x4
(1) 1/2" Type X No Ceiling Required 1-hour Fire-rated Assembly 2x4 2x4
(1) 5/8" Type X No Ceiling Required 45-min Fire-rated Assembly 2x6 2x4
(2) 1/2" Type X No Ceiling Required 1/2" Type X 2x6 2x4
(2) 5/8" Type X No Ceiling Required No Ceiling Required 2x6 2x4
1-1/2
Unprotected No Ceiling Required 1-hour Fire-rated Assembly 2x4 2x4
(1) 1/2" Type X No Ceiling Required 5/8" Type X 2x6 2x4
(1) 5/8" Type X No Ceiling Required 5/8" Type X 2x6 2x4
(2) 1/2" Type X No Ceiling Required No Ceiling Required 2x6 2x4
(2) 5/8" Type X No Ceiling Required No Ceiling Required 2x6 2x6
1-3/4
Unprotected No Ceiling Required 1-hour Fire-rated Assembly 2x4 2x4
(1) 1/2" Type X No Ceiling Required 1/2" Type X 2x6 2x4
(1) 5/8" Type X No Ceiling Required 1/2" Type X 2x6 2x4
(2) 1/2" Type X No Ceiling Required No Ceiling Required 2x6 2x6
(2) 5/8" Type X No Ceiling Required No Ceiling Required 2x6 2x6
1) Rim assembly for fire from either side of wall. “With load transfer” assumes load transfers to the adjacent rim board if the fire exposed rim
board fails.
2) Gypsum wallboard shown on the ceiling is to protect the rim board only. It does not necessarily cause the floor assembly to be rated.
3) Attach 1-layer Type X (1/2 or 5/8-inch) gypsum wallboard to rim board with 1-1/2-inch Type W drywall screws spaced 12 inches o.c.
4) Attach 2-layer Type X (1/2 or 5/8-inch) gypsum wallboards to rim board with 2-inch Type W drywall screws spaced 12 inches o.c.
5) Provide min. 1-3/4-inch bearing for I-joist.
6) Use only fire rated gypsum wallboard. Type C may be substituted for Type X.
7) Rim board and gypsum wallboard thicknesses are shown as minimums. Thicker rim board and gypsum wallboard may be substituted.
8) Toenailing from the I-joist flange to the rim is permitted. When 2-layer gypsum wallboards are used, I-joist end nails shall be 16d box
(0.135 inch x 3-1/2 inches) nails.
9) Rim board needs to be sized for vertical and lateral loads.

6. Form No. D350B ■ © 2015 APA – The Engineered Wood Association ■ www.apawood.org 6
Data File: APA Rim Board in Fire-Rated Assemblies
FIRE RESISTANCE R ATED RIM BOARD ASSEMBLY RB5
This fire resistance design is listed in accordance with ASTM E119 and CAN/ULC S101
RB5
RB6
LoadLoad LoadLoad
LoadLoad LoadLoad
cials
Gypsum board (B)
Rim board (A)
Ceiling and wall ratings
as required by Building Officials
Ceiling membrane (C)
Stud (D)
Rated wall assembly
Gypsum board (B)
Rim board (A)
Ceiling and wall ratings
as required by Building Officials
Ceiling membrane (C)
Stud (D)
Rated wall assembly
Gypsum board (B)
Rim board (A)
Ceiling and wall ratings
as required by Building Officials
Ceiling membrane (C)
Stud (E)
Rated wall assembly
Gypsum board (B)
Rim board (A)
Ceiling and wall ratings
as required by Building Officials
Ceiling membrane (C)
Stud (E)
Rated wall assembly
ficials
Jan. 4, 2013
Fire_Assembly_Bosie_Rim_Board_2013_v4.eps
Same as
right-hand
side drawing
Same as
right-hand
side drawing
Same as
right-hand
side drawing
Same as
right-hand
side drawing
Same as
right-hand
side drawing
Same as
right-hand
side drawing
Same as
right-hand
side drawing
Same as
right-hand
side drawing
DOUBLE WALL CONFIGURATION WITH NO LOAD TRANSFER BASE ASSEMBLY
Rim Board
Thickness, in.
Rim Board
Protection
Ceiling Membrane Req.
for 1-hr
Ceiling Membrane Req.
for 2-hr
Stud
Size
Stud
Size
A B C C D E
1
Unprotected 5/8" Type X 2-hour Fire-rated Assembly 2x4 2x4
(1) 1/2" Type X 1/2" Type X 90-min Fire-rated Assembly 2x4 2x4
(1) 5/8" Type X 1/2" Type X 90-min Fire-rated Assembly 2x4 2x4
(2) 1/2" Type X No Ceiling Required 5/8" Type X 2x6 2x4
(2) 5/8" Type X No Ceiling Required 1/2" Type X 2x6 2x4
1-1/8
Unprotected 5/8" Type X 2-hour Fire-rated Assembly 2x4 2x4
(1) 1/2" Type X 1/2" Type X 90-min Fire-rated Assembly 2x4 2x4
(1) 5/8" Type X 1/2" Type X 90-min Fire-rated Assembly 2x4 2x4
(2) 1/2" Type X No Ceiling Required 5/8" Type X 2x6 2x4
(2) 5/8" Type X No Ceiling Required 1/2" Type X 2x6 2x4
1-1/4
Unprotected 5/8" Type X 2-hour Fire-rated Assembly 2x4 2x4
(1) 1/2" Type X 1/2" Type X 90-min Fire-rated Assembly 2x4 2x4
(1) 5/8" Type X 1/2" Type X 90-min Fire-rated Assembly 2x6 2x4
(2) 1/2" Type X No Ceiling Required 5/8" Type X 2x6 2x4
(2) 5/8" Type X No Ceiling Required 1/2" Type X 2x6 2x4
1-1/2
Unprotected 1/2" Type X 90-min Fire-rated Assembly 2x4 2x4
(1) 1/2" Type X 1/2" Type X 90-min Fire-rated Assembly 2x6 2x4
(1) 5/8" Type X No Ceiling Required 1-hour Fire-rated Assembly 2x6 2x4
(2) 1/2" Type X No Ceiling Required 1/2" Type X 2x6 2x4
(2) 5/8" Type X No Ceiling Required 1/2" Type X 2x6 2x6
1-3/4
Unprotected 1/2" Type X 90-min Fire-rated Assembly 2x4 2x4
(1) 1/2" Type X No Ceiling Required 1-hour Fire-rated Assembly 2x6 2x4
(1) 5/8" Type X No Ceiling Required 1-hour Fire-rated Assembly 2x6 2x4
(2) 1/2" Type X No Ceiling Required 1/2" Type X 2x6 2x6
(2) 5/8" Type X No Ceiling Required No Ceiling Required 2x6 2x6
1) Rim assembly for fire from either side of wall. “With no load transfer” assumes no load transfers to the adjacent rim board if the fire
exposed rim board fails.
2) Gypsum wallboard shown on the ceiling is to protect the rim board only. It does not necessarily cause the floor assembly to be rated.
3) Attach 1-layer Type X (1/2 or 5/8-inch) gypsum wallboard to rim board with 1-1/2-inch Type W drywall screws spaced 12 inches o.c.
4) Attach 2-layer Type X (1/2 or 5/8-inch) gypsum wallboards to rim board with 2-inch Type W drywall screws spaced 12 inches o.c.
5) Provide min. 1-3/4-inch bearing for I-joist.
6) Use only fire-rated gypsum wallboard. Type C may be substituted for Type X.
7) Rim board and gypsum wallboard thicknesses are shown as minimums. Thicker rim board and gypsum wallboard may be substituted.
8) Toenailing from the I-joist flange to the rim is permitted. When 2 layer gypsum wallboards are used, I-joist end nails shall be 16d box (0.135
inch x 3-1/2 inches) nails.
9) Rim board needs to be sized for vertical and lateral loads.

7. Form No. D350B ■ © 2015 APA – The Engineered Wood Association ■ www.apawood.org 7
Data File: APA Rim Board in Fire-Rated Assemblies
FIRE RESISTANCE R ATED RIM BOARD ASSEMBLY RB6
This fire resistance design is listed in accordance with ASTM E119 and CAN/ULC S101
RB6
LoadLoad LoadLoad
Gypsum board (B)
Rim board (A)
Ceiling and wall ratings
as required by Building Officials
Ceiling membrane (C)
Stud (D)
Rated wall assembly
Gypsum board (B)
Rim board (A)
Ceiling and wall ratings
as required by Building Officials
Ceiling membrane (C)
Stud (E)
Rated wall assembly
Jan. 4, 2013
Fire_Assembly_Bosie_Rim_Board_2013_v4.eps
Same as
right-hand
side drawing
Same as
right-hand
side drawing
Same as
right-hand
side drawing
Same as
right-hand
side drawing
DOUBLE WALL CONFIGURATION WITH NO LOAD TRANSFER BASE ASSEMBLY
Rim Board
Thickness, in.
Rim Board
Protection
Ceiling Membrane
Req. for 1-hr
Ceiling Membrane
Req. for 2-hr
Stud
Size
Stud
Size
A B C C D E
1
Unprotected 5/8" Type X 2-hour Fire-rated Assembly 2x4 2x4
(1) 1/2" Type X 1/2" Type X 90-min Fire-rated Assembly 2x4 2x4
(1) 5/8" Type X 1/2" Type X 90-min Fire-rated Assembly 2x4 2x4
(2) 1/2" Type X No Ceiling Required 5/8" Type X 2x6 2x4
(2) 5/8" Type X No Ceiling Required 1/2" Type X 2x6 2x4
1-1/8
Unprotected 5/8" Type X 2-hour Fire-rated Assembly 2x4 2x4
(1) 1/2" Type X 1/2" Type X 90-min Fire-rated Assembly 2x4 2x4
(1) 5/8" Type X 1/2" Type X 90-min Fire-rated Assembly 2x4 2x4
(2) 1/2" Type X No Ceiling Required 1/2" Type X 2x6 2x4
(2) 5/8" Type X No Ceiling Required 1/2" Type X 2x6 2x4
1-1/4
Unprotected 5/8" Type X 2-hour Fire-rated Assembly 2x4 2x4
(1) 1/2" Type X 1/2" Type X 90-min Fire-rated Assembly 2x4 2x4
(1) 5/8" Type X No Ceiling Required 1-hour Fire-rated Assembly 2x6 2x4
(2) 1/2" Type X No Ceiling Required 1/2" Type X 2x6 2x4
(2) 5/8" Type X No Ceiling Required 1/2" Type X 2x6 2x4
1-1/2
Unprotected 1/2" Type X 90-min Fire-rated Assembly 2x4 2x4
(1) 1/2" Type X 1/2" Type X 90-min Fire-rated Assembly 2x6 2x4
(1) 5/8" Type X No Ceiling Required 1-hour Fire-rated Assembly 2x6 2x4
(2) 1/2" Type X No Ceiling Required 1/2" Type X 2x6 2x4
(2) 5/8" Type X No Ceiling Required No Ceiling Required 2x6 2x6
1-3/4
Unprotected 1/2" Type X 90-min Fire-rated Assembly 2x4 2x4
(1) 1/2" Type X No Ceiling Required 1-hour Fire-rated Assembly 2x6 2x4
(1) 5/8" Type X No Ceiling Required 45-min Fire-rated Assembly 2x6 2x4
(2) 1/2" Type X No Ceiling Required No Ceiling Required 2x6 2x6
(2) 5/8" Type X No Ceiling Required No Ceiling Required 2x6 2x6
1) Rim assembly for fire from either side of wall. “With no load transfer” assumes no load transfers to the adjacent rim board if the fire
exposed rim board fails.
2) Gypsum wallboard shown on the ceiling is to protect the rim board only. It does not necessarily cause the floor assembly to be rated.
3) Attach 1-layer Type X (1/2 or 5/8-inch) gypsum wallboard to rim board with 1-1/2-inch Type W drywall screws spaced 12 inches o.c.
4) Attach 2-layer Type X (1/2 or 5/8-inch) gypsum wallboards to rim board with 2-inch Type W drywall screws spaced 12 inches o.c.
5) Provide min. 1-3/4-inch bearing for I-joist.
6) Use only fire-rated gypsum wallboard. Type C may be substituted for Type X.
7) Rim board and gypsum wallboard thicknesses are shown as minimums. Thicker rim board and gypsum wallboard may be substituted.
8) Toenailing from the I-joist flange to the rim is permitted. When 2-layer gypsum wallboards are used, I-joist end nails shall be 16d box
(0.135 inch x 3-1/2 inches) nails.
9) Rim board needs to be sized for vertical and lateral load.

8. APA Rim Board® in Fire-Rated Assemblies
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who can help answer questions involving APA trademarked products.
For additional assistance in specifying engineered wood products, contact us:
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DISCLAIMER
The information contained herein is based on APA – The Engineered Wood Association’s
­continuing programs of laboratory testing, product research, and comprehensive field experi-
ence. Neither APA, nor its members make any warranty, expressed or implied, or assume any
legal liability or responsibility for the use, application of, and/or reference to opinions, findings,
conclusions, or recommendations included in this publication. Consult your local jurisdiction or
design professional to assure compliance with code, construction, and performance require-
ments. Because APA has no control over quality of workmanship or the conditions under which
engineered wood products are used, it cannot accept responsibility of product performance or
designs as actually constructed.
Form No. D350B/Revised February 2015