A deck extends usable living space outdoors to support sunrise breakfasts, lunchtime barbecues and evening cocktail parties. A railing around a structure -- especially if it's elevated several feet above the ground -- protects homeowners, family and friends from falling off and injuring themselves. For maximum safety, these rails must approach a standard height.
The International Residential Code is used by local, state and some federal jurisdictions to define construction standards such as the height of a deck rail. The International Code Council, a member organization, defines these standards to promote building safety in affordable construction projects around the world. The ICC also defines other codes that can affect deck rails, such as the International Building Code, the International Existing Building Code and the International Maintenance Code.
The IRC specifies that the height of guardrails around decks must be at least 36 inches high. Any style or pattern of spindle to support the rail is allowed. However, the space between spindles must not be big enough to allow a sphere 4 inches in diameter to pass through. This prevents small children from being choked on the structures. Guardrails must also be strong enough to withstand up to 200 pounds of pressure at the top. This requires support posts spaced a maximum of 6 feet from one other.
If the deck has stairsteps leading to it, handrails for the steps must be 34 to 38 inches high. The height must be uniform throughout the entire flight of steps as measured from the bottom of the tread to the top of the rail. The top of the rail must remain uninterrupted by bumps, posts, decorations or other fittings that can interrupt the movement of the hand. The clearance between the handrail and a wall or other surface must be a minimum of 1 1/2 inches. The handrail must be grippable. If it's circular, the outside diameter must range from 1 1/4 to 2 inches. If it isn't circular, the perimeter dimension must be 4 to 6 1/4 inches, with cross sections measuring 1 to 2 1/4 inches.
To ensure safety, a deck and its railings need inspections and approval by building code authorities before anyone can set foot on it. Some jurisdictions mandate railings if a deck is as little as 18 inches from the ground. The top and bottom rails must be attached to vertical members attached to the deck frame itself, not just to the deck surface. Otherwise, the members may detach, causing guardrails to fail, warns the website NADRA.org.
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