• A guardrail is meant to prevent injury.Relaxing Deck image by gardenia from Fotolia.com
  
  Deck rail protection is required by law in California when you mount a patio deck standing at least 36 inches. The design of the guardrail will only be compliant to regulations if the height, surface and end projection of the top rail can meet the standard specifications. The deck must be constructed in such a way anyone, regardless of age, can use it securely.
  
  

Applying for a Permit

• You will need a permit from your local Planning and Development Department to make modifications if you are mounting a patio deck that is at least 30 inches high. The application has to be accompanied by an elaborate plan that shows specifically the kind of changes you intend to make to your property. A list of the type of material to be used for construction is also required. For example, the Planning and Development Department would like to know if the kind of wood that will be used is treated or if it is strong enough to withstand the stresses of the number of people intended to use it. The whole purpose is to prevent it from collapsing and injuring people.
  
  

A Standard Guardrail

• The deck rails must have a top rail, mid-rail and posts, while the vertical height should measure between 42 and 45 inches above the floor of the deck. The railing must be smooth and easy to hold for anyone using it. The mid rail should be halfway between the top rail and the surface of the deck. The idea is to prevent, for example, children slipping through spaces and falling off the patio. The guardrail must also be able to handle 20 pounds per linear foot at the top of the rail. These are minimum requirements. If the deck will be used by crowds, additional strength has to be provided, for example, by the use of heavier stock.
  
  

Other Acceptable Guardrail Specifications

• When wood is used, cases when the patio will be used by crowds of people, the wood must be at least 2-inch-by-4-inch, spaced within 6 feet and with rounded top corners. If metal is used, the top rail has to be angle iron of an least 2-inch-by-2-inch by one-fourth-inch angles.