The statement “the maximum height at which a scaffold should be placed is 20 feet” is referring to a specific type of scaffold, not to all scaffolds in general.

Direct answer

In common safety and construction question banks, the item:

“The maximum height at which a ____ scaffold should be placed is 20 feet.”

is correctly completed as:

“The maximum height at which a ladder jack scaffold should be placed is 20 feet.”

So, the full sentence should be:

“The maximum height at which a ladder jack scaffold should be placed is 20 feet.”

Why 20 feet matters

  • Ladder jack scaffolds are small, portable platforms supported by ladders, so they are less stable than larger, engineered scaffold systems.
  • Because of that lower inherent stability, safety guidelines limit their maximum working height to about 20 feet to reduce the risk of falls and tipping.

Not a universal scaffold limit

  • Other scaffold types (e.g., tubular welded frames, rolling towers, suspended scaffolds) follow different rules, often based on a height‑to‑base ratio such as 4:1, and can safely exceed 20 feet when properly designed, tied, and guarded.
  • Regulatory standards like OSHA focus on fall protection starting above 10 feet, guardrail heights, and stability ratios, rather than a single universal height like 20 feet for all scaffolds.

Bottom note: Information gathered from public forums or data available on the internet and portrayed here.