Q. Are there OSHA-specific guidelines for installing and using roof jacks? Is any additional fall protection required when working off properly installed roof jacks?
A. Andrew Wormer, JLC’s executive editor, responds: When roof jacks are properly fastened to the roof according to the manufacturer’s instructions, they add both an element of safety and a useful work platform on sloped roofs. But Peter Barletta, a compliance assistance specialist working out of OSHA’s Boston South Office in Braintree, Mass., says that most of the simple and inexpensive adjustable roof brackets you are probably familiar with aren’t equipped with integral guardrails, and unless they are (as shown in the photo at right), they aren’t a substitute for an OSHA-approved fall protection system. Barletta says that this would typically consist of a full body harness connected to a shock-absorbing or retractable lanyard hooked to a manufactured roof anchor capable of supporting a 5,000-pound load per attached employee. Alternatively, a personal fall protection system with a safety factor of two could be designed, installed, and used under the supervision of a qualified person. Fall protection is always required on roofs where the distance between the eaves and the ground or a lower surface is 6 feet or greater, regardless of the presence of roof jacks.
Don’t use roofing nails to install roof jacks; the shanks are too short, the diameters are too small, and the heads—though broad—will pop off easily. Instead, use 8d or 16d common nails driven through the sheathing into the framing. Most roof jacks are adjustable, and after installation, the platform should be level.
For the most stability and to limit flexing, try to use the widest staging planks that will fit in the roof jack. For example, if the roof jack will accept a 2x10 plank, that is what you should use, not a 2x6 or a 2x8. According to OSHA guidelines, the planking primarily must be able to support, without failure, its own weight and at least four times the intended load. In addition, when fully loaded, the plank should not deflect more than 1/60 of the span; that is, a 10-foot staging plank should deflect no more than 2 inches.
Locate the roof jacks within 6 to 12 inches of the end of the staging planks so that when a worker steps on the cantilevered portion of the staging plank, there is not enough leverage to lift the other end of the plank off its support. If the roof is wide and requires multiple staging planks, overlap them by 1 or 2 feet, locating the overlap above one of the jacks. Fastening the planks together with nails or screws will reinforce the assembly and make it more stable.