What is the maximum allowable height for a guardrail on a deck?

The maximum allowable height for a guardrail on a deck is commonly set at 36 inches. This height standard is established to provide adequate safety while also considering practicality. A guardrail at this height is effective in preventing falls from elevated surfaces, ensuring that it is tall enough to deter accidental slips without obstructing the view or causing inconvenience for users of the space. Building codes, such as the International Residential Code (IRC), often specify this standard, making it a widely accepted regulation.

When assessing the other options, 30 inches is generally considered too low for effective fall protection, as it doesn't provide sufficient barrier against falls from elevated decks. Heights of 42 inches and 48 inches exceed the maximum requirement and may create issues such as being cumbersome or obstructing the view, which can detract from the experience and functionality of the deck area. Therefore, the choice of 36 inches aligns with safety standards while balancing user comfort and structural integrity.