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 https://www.osha.gov.

August 3, 1999

[Name & Address Withheld]

Re: STD 3.1, 1926.500; Subpart M

[This document was edited on 12/5/12 to strike information that no longer reflects current OSHA policy.]

Dear [Name Withheld]:

This is in response to your letter dated March 29, 1999, to the Occupational Safety and Health Administration (OSHA), in which you asked if there were any feasible means to control and protect employees from falling off the building during the construction and installation of the roof framing, trusses, and components.

Employers are protecting employees from fall hazards in these operations in several ways. Below are some that we are aware of:

  1. Some employers are assembling the roof as a unit on the ground and then raising it by crane.
  2. Another method involves the use of both roof anchors (permanent as well as removable anchors are available) and reusable truss braces.1 The reusable truss braces allow the trusses to be braced without being on them. In this type of system, one end of the device is attached to the truss on the ground (the other end has a rope attached to it). The truss is then erected either by crane or manually. Two methods are commonly used to erect them manually. In both approaches workers at either end of the truss work from ladders or platforms. In one approach the workers directly lift and place the truss on the top plates. In the other approach, the truss is first placed upside down between the exterior walls. The workers then rotate it up into place on the top plates. In either case, one or more roof anchors are also attached to one or more strategically located trusses before those trusses are erected.

Once the truss is raised, a worker on the floor level pulls the rope that is attached to the other end of the brace, which brings that end of the brace down onto the adjoining truss. At that point the brace is locked onto both trusses. The process is repeated as each truss is erected. Depending on the size of the truss, two or more braces are used per truss.

With all the braces locked in place, the trusses can now be sheathed. The initial courses of sheathing, beginning at the eaves, are installed by workers who are on the inside of the structure on platforms. They remove the braces one at a time, as each sheet of sheathing is installed.

Some employers will install all but the last (top) course from platforms on the inside. The last course is then sheathed by workers on the roof who are tied-off to the previously installed roof anchor(s). Others install added (wood) bracing sufficient to support a roof anchor so that the almost all of the sheathing courses can be installed by workers on the roof while tied-off.

Once the sheathing is done, the weather-proofing material and roof-mounted equipment can be installed with workers tied-off to the previously installed roof anchor(s).

There are a number of different types of roof anchors available for use during sheathing. Many are made of metal and attach by screws or nails to a truss or framing members. Another type is comprised of a D-ring attached to a fabric strap. The strap is nailed to and wrapped around one or more roof trusses. The anchor is removed by cutting the D-ring from the strap or using double-headed nails to allow the nails and the strap to be removed.

For further information on fall protection in residential construction, you may want to contact:

National Safety Council
1121 Spring Lake Drive
Itasca, IL 60143-3201
(800) 539-7468

United Brotherhood of Carpenters
Health and Safety Fund of North America
101 Constitution Avenue, NW
Washington, D.C. 20001
(202) 546-6206

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

[Corrected 6/2/2005]

1 OSHA does not approve or endorse specific products. [Back to text]