Dimensions of a Deck

Important Dimensions of a Deck

• The most important factors that affect the ultimate dimensions of your deck are the support structure, access and its overall safety. Vertical support posts are generally required to be between 4 and 8 feet apart -- most often 6 feet -- with joists running under the deck being between 16 and 24 inches apart and supported by piers for spans greater than 8 feet. Steps in an access stairway need to be at least 36 inches across and 10 inches wide, and a rise between each step should be no more than 7 ½ inches. Railings are required as well. These will attach to the support posts, and spaces between railings should not be larger than 4 inches to prevent somebody's head from becoming stuck in the space.

What's the Goal?

• Do you need a little space to put a lawn chair and a grill? Or do you want to go all out and have a large party area that may even include some landscaping? Decide what the goal is before planning an outdoor deck. This will affect the ultimate dimensions of the deck and will also affect the overall design. Factors to consider are how the size of the deck will blend with the size of the home and how it will complement the home's style. Also, consider any landscaping. Trees and flower beds should be incorporated into the overall design, and all of these factors will affect the ultimate dimensions of your deck.

Other Exterior Factors

• Besides the overall look of the outdoor deck, keep in mind some other important considerations in the design. Air currents and sun exposure should be maximized for full enjoyment of the outdoor environment. Design the deck so that you get the best view. Safety for children and the elderly is important, as is the location of any utility lines or drainage systems. You must not block access to these, so consult local utility companies and building codes for advice and instructions.

Building Codes

• Check with the local code enforcement office before starting an outdoor deck project. This is important, because even if you are familiar with carpentry, the local building codes may be different than what you're used to. And if a code inspector comes by and sees that your dimensions are different than code, you have wasted some time and possibly some money. Basic deck dimensions, regardless of the locale, always factor in the lot size, the terrain as it relates to the depth of deck post holes and the elevation of the deck from the ground.