Alert: Due to routine maintenance on the OSHA website, some pages may be temporarily unavailable.
To report an emergency, file a complaint with OSHA or ask a safety and health question, call 1-800-321-6742 (OSHA).

OSHA requirements are set by statute, standards and regulations. Our interpretation letters explain these requirements and how they apply to particular circumstances, but they cannot create additional employer obligations. This letter constitutes OSHA's interpretation of the requirements discussed. Note that our enforcement guidance may be affected by changes to OSHA rules. Also, from time to time we update our guidance in response to new information. To keep apprised of such developments, you can consult OSHA's website at

May 18, 2006

Mr. Carroll Buchanan
ESI Group, Inc.
102 North 20th Street
Tampa, FL 33605

Re: Whether plywood may be used as scaffold decking material over wood scaffold planks; 29 CFR 1926.450 and 1926.451

Dear Mr. Buchanan:

This is in response to your fax submitted October 21, 2005, to the Occupational Safety and Health Administration (OSHA). Your question relates to the use of plywood as platform decking over wood scaffold planks. We apologize for the delay in responding.

We have paraphrased your question as follows:

Question (1): Does the OSHA scaffold standard for construction (Part 1926 Subpart L) allow for the use of 5/8'' four-ply exterior grade plywood to be used as decking over wood support planks on a combination of tube and coupler, frame, and systems type scaffold?

Answer: It is permissible, under certain conditions, to use plywood as platform decking material. OSHA's construction industry standards addressing scaffolds are in 29 CFR Part 1926, Subpart L.

Title 29 CFR 1926.450(b) provides:

(b) Definitions.
* * *
Fabricated decking and planking means manufactured platforms made of wood (including laminated wood, and solid sawn wood planks), metal or other materials. [Emphasis added.]
* * *
Platform means a work surface elevated above lower levels. Platforms can be constructed using individual wood planks, fabricated planks, fabricated decks, and fabricated platforms.
* * *
Qualified means one who, by possession of a recognized degree, certificate, or professional standing, or who by extensive knowledge, training, and experience, has successfully demonstrated his/her ability to solve or resolve problems related to the subject matter, the work, or the project.
* * *

Title 29 CFR 1926.451(a) provides:

(a) Capacity. (1) . . . [E]ach scaffold and scaffold component shall be capable of supporting without failure, its own weight and at least 4 times the maximum intended load applied or transmitted to it. [Emphasis added.]
* * *
(6) Scaffolds shall be designed by a qualified person and shall be constructed and loaded in accordance with that design. Non-mandatory Appendix A to this subpart contains examples of criteria that will enable an employer to comply with paragraph (a) of this section. [Emphasis added.]

Title 29 CFR 1926.451(b)(1)(i) provides:

(b) Scaffold platform construction. (1) Each platform on all working levels of scaffolds shall be fully planked or decked between the uprights and the guardrail supports as follows:
(i) Each platform unit (e.g., scaffold plank, fabricated plank, fabricated deck, or fabricated platform) shall be installed so that the space between adjacent units and the space between the platform and the uprights is no more than 1 inch wide, except where the employer can demonstrate that a wider space is necessary . . . .

Title 29 CFR 1926.451(f)(1) and (f)(16) provide:

(f) Use. (1) Scaffolds and scaffold components shall not be loaded in excess of their maximum intended loads or rated capacities, whichever is less.
* * *
(16) Platforms shall not deflect more than 1/60 of the span when loaded.

Employers must ensure that scaffolds are designed, erected, and maintained in accordance with the applicable provisions of Subpart L of Part 1926. The requirements for scaffold platforms are written to allow flexibility of design by a qualified person, so long as they meet all the applicable criteria. Subpart L does not mandate a particular material to be used for a scaffold deck.

If the use of plywood over wood planks results in a scaffold (and each scaffold component) designed by a qualified person that meets the capacity requirements with a deflection of no more than 1/60 of the span when loaded, it would meet the performance requirements of Subpart L.

Question (2): Is it permissible under Subpart L to use the "APA —Engineered Wood Association Load Span Tables for APA Structural-Use Panels" as a basis for scaffold design?

Answer: As discussed in our answer to Question (1) above, Subpart L specifies a result that the scaffold design must attain and that the design be done by a qualified person. The method for developing the design is not specified by the standard.

As a practical matter, to achieve the results specified by the standard, the qualified person has to use data that is reliable in developing his or her design. Our understanding is that the Tables you refer to are used in the industry as a standard engineering reference tool. Consequently, we are unaware of any reason why a qualified person would be unable to rely on that data as a starting point in designing a scaffold platform.

If you need additional information, please contact us by fax at: U.S. Department of Labor, OSHA, Directorate of Construction, Office of Construction Standards and Guidance, fax # 202-693-1689. You can also contact us by mail at the above office, Room N3468, 200 Constitution Avenue, N.W., Washington, D.C. 20210, although there will be a delay in our receiving correspondence by mail.


Russell B. Swanson, Director
Directorate of Construction



1 We addressed a similar question on our June 21, 2004, letter to Mr. Randy Wheeler. This letter can be viewed on OSHA's website at: [ back to text ]