An Integral System Component
Rim board is the trusted choice for engineered wood floor systems, delivering greater dimensional stability, higher strength, and more consistent quality than sawn lumber. Rim board may be manufactured with plywood, oriented strand board (OSB), glued laminated timber (glulam), or laminated veneer lumber (LVL). Manufactured to match the depth of wood I-joists and tested to meet rigorous performance standards, it provides reliable transfer of both vertical and lateral loads — keeping your structure tight, compliant, and built to last.
Designed to match the depth of wood I-joists and other engineered wood framing, rim board delivers the structural performance and dimensional consistency that sawn lumber simply cannot reliably provide.
Engineered for use with wood I-joists: Maintains the tight dimensional fit needed for full transfer of axial and lateral loads, unlike sawn lumber rim boards that can shrink up to 1/2 inch in height.
Superior structural performance: Greater dimensional stability, higher strength, and more consistent quality than sawn lumber.
Versatile across a wide range of applications: Suitable for standard floor framing, spanning openings up to four feet, deck ledger attachment, and fire blocking.
Rim board is an integral component of engineered wood floor systems, performing a range of structural and code-compliance functions across residential and commercial construction.
Standard floor framing: Fills the space between the sill plate and wall plates, tying floor joists together and transferring both vertical bearing and lateral forces through the floor assembly.
Spanning openings: Can be used as a single or double-ply beam to span openings up to 4 feet, depending on applied loads.
Deck ledger attachment: Provides a solid connection point for 2x lumber ledgers using 1/2-inch diameter lag screws or through-bolts.
Fire blocking: Minimum 1-inch thickness exceeds the 23/32-inch requirement in model building codes, making it suitable for use as a fire blocking panel.
From standard floor framing to fire-rated assemblies, rim board is engineered to meet the demands of modern wood construction.
Selecting the appropriate rim board requires evaluating materials, depth/thickness and load span requirements. The following guidelines can be used when specifying APA Performance Rated Rim Board for residential floor applications.
Materials: Rim board may be manufactured from plywood, oriented strand board (OSB), glued laminated timber (glulam), or structural composite lumber (SCL), which includes LVL, LSL, and OSL. As glued engineered wood products, they offer greater dimensional stability, higher strength, and a lower tendency to check or split compared to sawn lumber.
Rim board sizes: Standard depths range from 9 1/2 to 24 inches, and the rim board must match the depth of the framing members to function properly. Standard thicknesses are 1, 1 1/8, 1 1/4, and 1 1/2 inches, with lengths available from 8 to 24 feet depending on the product.
Load span: Rim board grade and size selection shall be based on joist depth and applicable loading using Table 3 of APA Performance Rated Rim Boards, Form W345 and rim boards may span openings up to 4 feet using the allowable uniform loads in Tables 5A or 5B of APA Performance Rated Rim Boards, Form W345. For openings greater than 4 feet, glulam, SCL, or other engineered wood bending members should be used instead.
Connections & fasteners: Floor sheathing shall be attached to the rim board using 8d nails (box or common) at 6 inches o.c., and the rim board shall be toenailed to the sill plate using 8d nails at 6 inches o.c. For deck ledger attachments, use 1/2-inch-diameter lag screws (minimum 4-inch nominal length) or through-bolts with washers, staggered in two rows per the spacing requirements of Table 2 of APA Performance Rated Rim Boards, Form W345.
Code compliance & performance standards: APA Performance Rated Rim Boards shall conform to ANSI/APA PRR 410 or APA PRR-401, both of which meet or exceed the ICC-ES Acceptance Criteria for Wood-Based Rim Board Products (AC124). As defined in the International Building Code (IBC) and International Residential Code (IRC), the rim board must also comply with ASTM D7672 to satisfy the applicable code definition for engineered wood rim board products.
For comprehensive specification guidance, load span tables, and technical specifications, download the APA Performance Rated Rim Board Selection & Specification Guide or APA Performance Rated Rim Boards, Form W345.
APA PERFORMANCE RATED RIM BOARD SELECTION & SPECIFICATION GUIDE
APA PERFORMANCE RATED RIM BOARDS
Understanding the APA trademark ensures you select the rim board that meets the demands of your project.
Selecting the right rim board begins with understanding the loads it will be required to carry. Rim board must be sized to handle both vertical bearing loads from the wall above and lateral forces transferred through the floor system. The load span tables provided by APA make it straightforward to identify the appropriate rim board size and grade for your application.
Complete load span tables are available in APA Performance Rated Rim Boards, Form W345 or refer to the manufacturer’s APA Product Report.
APA PERFORMANCE RATED RIM BOARDS
APA Form W345, Table 3 - Allowable Design Capacities: Designers can use this table to verify that the selected rim board grade and thickness meets the required horizontal load transfer capacity (H), uniform vertical load capacity (V), concentrated vertical load capacity (P), and lateral resistance (Z). Grade and size selection should be based on joist depth and applicable loading conditions.
APA Form W345, Tables 5A and 5B - Allowable Uniform Loads for Spanning an Opening: These tables can be used when a rim board must span an opening of up to 4 feet, with data for both standard and OSB APA Performance Rated Rim Boards. The designer should identify the rim board size (thickness × depth), determine whether a single or double-ply configuration is required, and locate the allowable total load (lbf/ft) that corresponds to the applicable span length. Minimum end bearing requirements vary by span and must also be satisfied. For openings greater than 4 feet, glulam, SCL, or another engineered wood bending member should be specified.
APA Form W345, Table 4 - Allowable Edgewise Bending Properties: This table provides design values for applications outside the scope of Tables 5A and 5B.
APA member manufacturers produce rim board that meets stringent quality standards verified through APA's rigorous testing and inspection programs. Specifying rim board bearing the APA trademark, manufactured by APA members, ensures you receive products that have been qualified to published performance standards and are backed by ongoing quality assurance testing from a trusted third party.
Manufactured to recognized U.S and Canadian standards
Subject to ongoing quality assurance and product testing
Produced by companies with proven expertise in engineered wood products
Supported by APA technical resources, evaluation, and industry oversight
Use the APA manufacturer directory to locate member manufacturers and explore the range of rim board and other engineered wood products they produce.
Optimizing Floor System Performance with Engineered Wood Products
59 minutes
Holes in Structural Glued Laminated Timber (Glulam) Rim Board in Light-Frame Wood Construction
Provides recommendations for hole size and segment length for glulam rim board for situations where holes are not specified in the construction documents or shop drawings.
PDF, 5 pages
APA Performance-Rated Rim Boards
This publication details connection requirements and application notes for APA Performance Rated Rim Board
PDF, 11 pages
Technical Topic - TT-094
This publication provides tables of the minimum recommended nail spacing for APA EWS Rim Boards and I-joists.
Technical Guides - W345 CA
This publication describes connection requirements and application notes for APA Performance Rated Rim Board for Canadian Limit States Design
Technical Topic - TT-022
This publication discusses the structural superiority of using APA Performance Rated Rim Boards with prefabricated wood I-joists rather than sawn lumber rim boards.
Data File - D350
This publication provides recommendations for the use of APA rim board in conjunction with fire-rated wall/floor assemblies, based on the US Forest Product Laboratory testing
Technical Guides - W345
This publication details connection requirements and application notes for APA Performance Rated Rim Board
Standards - ANSI/APA PRR 410
This standard provides requirements and test methods for qualification and quality assurance for performance rated engineered wood rim board.
The APA trademark is a quality and performance mark that verifies an engineered wood product meets recognized industry standards and conforms to APA’s stringent, third-party quality auditing procedures. On rim board, the stamp identifies the applicable product standard, intended structural application, and key performance characteristics needed for proper specification and use.
We do not have recommendations for APA Rated Sheathing or APA Rated Sturd-I-Floor for use in rim board applications.
APA Rated Sturd-I-Floor/Rated Sheathing and APA Performance Rated Rim Board are tested for compliance to different performance standards than other panel products. In the case of APA Rated Sturd-I-Floor, OSB panels are manufactured to PS 2. APA Rated Rim Board is manufactured to APA PRR-401 or PRR-410.
Refer to Connection Requirements #4 and Figure 3 & 4 of APA’s publication APA Performance Rated Rim Boards, Form W345.
APA Rim Board Performance Standard PRR-401 was first published in June 1997.