Floor Joist Spacing For Deck Boards

Adjust the spacing between deck boards gradually over the next 10 rows of decking until the distance to the house is equal.

Floor joist spacing for deck boards.

Table 1 2 or table 1 3 3. For a more rigid feel 12 or less may be preferred. Deck board spacing provides airflow through your decking allowing evaporating air to escape. Decking made of 2x4s or 2x6s can span up to 24 inches.

Deck joist spacing should never exceed 16 on center with the exception of max deck boards which allow for maximum 24 on center. Then using the lumber size of joists and the joist spacing determine if you are within the maximum allowable joist span. If you use 5 4 decking joists must be no farther apart than 16 inches. The larger the deck the larger the joists.

For best results refer to our wood and composite deck joist span table. Deck joists have a different maximum span length depending upon the size spacing and framing material that you re creating your deck with. The bigger you make your deck the more you ask of the framing timbers that hold up the deck s structure and the joists and beams that support the. Decide whether the joists will cantilever over or not.

In most cases it s best to start with a full board on the outside edge of the deck and work toward the house so the odd board is less visible. If adding additional framing be sure to keep all boards level and in plane across the tops. Here s a helpful chart covering the most popular wood framing species and their maximum allowed spans. This helps to keep your deck s framework dry and rot free.

Determine the decking board thickness and direction to determine joist spacing. I asked my local building official how he checks a deck plan to make sure the joist size and spacing combination will meet requirements of the building code he goes to the 40 lb. Recommended beam joist spans for deck framing. Decking boards span from joist to joist.

A house is only as strong as its foundation and a deck is only as strong as its frame. The last board won t look good if it s skinny or cut at an angle. In typical deck construction with a ledger on one side of the joist and beam on the other the size of the joists is driven by the size of the deck and based on the general maximum spans mentioned above. If you will run decking at an angle you might need to put the joists closer together.

While the gap in your deck boards may seem like a small step in a deck project the gap size you choose serves a significant purpose. Again it s important to know your local codes. Why the proper deck board spacing is important.