Joists & Rafters

Southern Pine
Joists and Rafters
Span Tables

Southern Pine has long been a preferred species for building construction because of its treatability, strength, and fastener-holding power. Southern Pine dimension lumber is readily available in wide widths, making it ideal for joists and rafters.

Users can choose from a variety of visual grades and an increasing supply of mechanical grades delivering a range of dependable strength and stiffness properties to meet the needs of any project. From framing a house to building a deck, Southern Pine lumber is one of the best construction products on the market today.

It’s also worth noting that Southern Pine’s strength and stiffness are comparable to other softwood species used in residential and commercial construction. Some lumber properties for Southern Pine are higher than for Spruce-Pine-Fir and Hem-fir, while others are the same or lower. The exact comparison, however, depends on the specific application and varies by grade and size.

The Southern Forest Products Association’s span tables for Southern Pine Joists and Rafters are easy-to-use and written for specific grades of Southern Pine lumber under common loading conditions.

Users of these span tables have the final responsibility for determining if the load and design assumptions represent actual conditions for their specific applications.

The 46 span tables below are for three types of framing members: floor joists, ceiling joists, and rafters. Spans in the tables are listed in feet and inches and are the maximum allowable horizontal span from inside-to-inside face of supports.

The tables below are based on design values for visually graded Southern Pine dimension lumber that became effective June 1, 2013.

TABLE NUMBER	LIVE LOAD (PSF)	DEAD LOAD (PSF)	DEFLECTION LIMIT
^{*Click on the table number to download a PDF for each application.}
Floor Joists
1	30	10	360
2	40	10	360
3	50	10	360
4	60	10	360
5	40	20	360
6	50	20	360
7	60	20	360
8	75	10	360
9	80	10	360
10	90	10	360
11	100	10	360
Wet-Service Floor Joists (MC > 19%)
12	40	10	360
13	60	10	360
14	100	10	360
Ceiling Joists
15	10	5	240
16	20	10	240
Rafters (Snow Load, CD = 1.15)
17	20	10	240
18	30	10	240
19	40	10	240
20	50	10	240
21	20	15	240
22	30	15	240
23	40	15	240
24	50	15	240
25	20	20	240
26	30	20	240
27	40	20	240
28	50	20	240
29	20	10	180
30	30	10	180
31	40	10	180
32	50	10	180
33	20	15	180
34	30	15	180
35	40	15	180
36	50	15	180
37	20	20	180
38	30	20	180
39	40	20	180
40	50	20	180
Rafters (Construction Load, CD = 1.25)
41	20	10	240
42	20	15	240
43	20	20	240
44	20	10	180
45	20	15	180
46	20	20	180
MC = Moisture Content		C_D = Load Duration Factor

Design Assumptions

General Requirements

The SFPA’s tables list maximum spans for Southern Pine joists and rafters assumes the quality of wood products and fasteners, and the design of load-supporting members and connections, conforms to the National Design Specification® (NDS®) for Wood Construction published by the American Wood Council (AWC). All members must be framed, anchored, tied, and braced to achieve the required strength and rigidity. Adequate bracing and bridging to resist wind and other lateral forces must be provided.

Spans

The spans provided in these tables were determined on the same basis as those given in the code-recognized Span Tables for Joists and Rafters and Wood Structural Design Data, both published by AWC. Maximum spans were computed using Allowable Stress Design (ASD) and standard engineering design formulas for simple span beams with uniformly distributed gravity loads.

The calculated spans assume fully supported members, properly sheathed and nailed on the top edge of the joist or rafter. They do not, however, include composite action of adhesive and sheathing. Listed spans also do not include checks for concentrated or partition loads that may be required by building codes for specific occupancy or use categories. Uplift loads caused by wind also have not been considered.

Download SFPA’s Southern Pine Maximum Spans for Joists & Rafters which includes all 46 tables, explains how to use these tables, provides examples of how to read the table values, and other important information about the proper application of Southern Pine joists and rafters.

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Disclaimer:

The primary purpose of this publication is to provide a convenient reference for joist and rafter spans for specific grades of Southern Pine lumber. The maximum spans provided herein were determined on the same basis as those in the code-recognized Span Tables for Joists and Rafters (2012 edition) and Wood Structural Design Data (1986 with 1992 revisions), both published by the American Wood Council (AWC).

SFPA does not grade or test lumber, and accordingly, does not assign design values to Southern Pine lumber. The design values contained herein are based on the Southern Pine Inspection Bureau’s Standard Grading Rules for Southern Pine Lumber (2002 edition with supplements) and modified as required by AWC’s National Design Specification® (NDS®) for Wood Construction (2012 edition).

Accordingly, SFPA does not warrant that the design values on which the span tables for Southern Pine lumber contained herein are based are correct, and specifically disclaims any liability for injury or damage resulting from the use of such span tables.

The conditions under which lumber is used in construction may vary widely, as does the quality of workmanship. Neither SFPA, nor its members, have knowledge of the quality of materials, workmanship or construction methods used on any construction project and, accordingly, do not warrant the technical data, design, or performance of the lumber in completed structures.