How to Stabilize a Deck

Measure the space between each of the joists which run beneath the surface of your deck. The joists should run perfectly parallel to one another so there is no need to repeat the measurement throughout the length of each joist.

Stretch the tape measure along each joist and mark the installation location for each piece of blocking. Make the first mark 3 feet into the first and second joists, and another mark every 3 feet after that. Make the first mark 3 1/2 feet into the other edge of the second joist and the third joist, then make another mark every 3 feet after that. To mark the space between the third and fourth joists, return to a 3 foot starting point. Continue this staggered approach throughout the remaining joists to create the proper grid pattern.

Count the number of markings you made to determine how many braces you need to cut. Cut 2-by-8 inch pressure treated lumber to serve as blocking in the spaces between your joists. Use the measurements taken and a circular saw to cut the lumber to fit.

Install one piece of blocking at each mark. Wedge the blocking in place at a mark between the two joists, then drive galvanized decking nails through the backside of the joist and into the blocking at each end. Move to the next mark and repeat the process until all the blocking has been installed.