How to Plank a Scaffold

Scaffold planks provide the walking surface for workers above ground.

Scaffolding is widely used in the construction industry as a platform for working above ground. Scaffolds are comprised of a scaffolding frame, rails and planks that provide the walking surface for workers. The use of scaffolds is regulated by the Occupational Safety & Health Administration to ensure safety for all workers. Planking a scaffold requires more than laying boards across a frame; workers must carefully inspect plank boards to ensure they meet safety regulations.

Instructions

1. Check each scaffold plank to ensure it is marked with a scaffold-grade stamp and an OSHA-approved stamp. Scaffold-grade lumber is designed to hold more weight than construction-grade lumber; using construction-grade lumber for scaffold planks is an OSHA violation.

2. Inspect each plank thoroughly for damage and signs of aging. Any plank that is split through the wood is rotten or has water damage. A plank covered with paint or other materials may have concealed damage. These defective planks should be discarded. Boards with surface cracks and notches on the ends should be monitored.

3. Use scaffold-grade planks that have only been used for their intended purpose. Planks that have been used to support scaffolds in mud, as ramps for wheelbarrows or to form a dry driving area in muddy conditions may be structurally compromised and could cause serious injury if used on scaffolding.

4. Consider the rated load capacity of the planks and the intended load weight when choosing planks for each scaffolding job. Different ratings may include light-duty, heavy-duty, one-person, two-person or three-person, which dictates the maximum weight per square foot and the appropriate dispersal of the weight over the plank surface.

5. Determine the maximum permissible span for the thickness of the lumber and the maximum intended load. Full-thickness lumber can span up to 10 feet with a load of 25 pounds per square foot, 8 feet with a load of 50 pounds per square foot and 6 feet for loads of 75 pounds per square foot. Nominal-thickness lumber is allowed for an 8-foot span with loads of 25 pounds per square foot and 6 feet for loads up to 50 pounds per square foot.

6. Lay the scaffold planks over the end supports of the scaffold frame. Ensure that any knots on the planks are facing up so they support weight better.

7. Position the planks so there is no more than 1 inch between any two planks and that they are no more than 9 inches from the vertical posts of the frame. If the frame does not have cleats where the ends can be placed, the boards must be long enough to extend at least 6 inches past each end support.

8. Observe the planks when in use to ensure they don't extend the maximum allowable deflection. The maximum permissible deflection according to OSHA standards is 2 inches for a span of 10 feet, 1-3/8-inches for 7 feet and 1 inch for spans of 5 feet. Immediately replace any boards that exceed this maximum.

Tips & Warnings

• Keep planks stored indoors in bundles, with stickers between the boards so air can circulate and reduce the risk of moisture damage.

• Damaged or questionable planks should be removed from service immediately because they could break, causing serious injury or death.

References

• Occupational Safety & Health Administration; Platform Planking
• "Masonry"; Scaffold Plank: Proper Care Increases Product Life and Safety; Jennie Farnsworth
• Scaffold Sales Online: Scaffold Safety
• University of Massachusetts-Amherst: Safe Scaffolds; Paul Fisette; 1997