What is a requirement when stacking lumber?

When stacking lumber, it is essential to stack it on level and solidly supported sills. This requirement ensures stability and safety in the workplace. When lumber is stacked properly, it minimizes the risk of tipping or collapsing, which could lead to injuries or accidents. Proper stacking on a stable base also allows for better organization and accessibility of materials, facilitating efficient work practices on construction sites.

The other choices do not align with safety standards. Piling lumber randomly on the ground can create hazardous situations, as unstable stacks might easily fall. Stacking lumber without any support compromises the integrity of the pile, increasing the likelihood of it collapsing. Stacking only on sloped surfaces is inherently unsafe, as it does not provide the necessary stability required for secure lumber storage. Therefore, stacking on level and solid supports is the only safe and proper method for handling lumber in construction environments.