A wobbly railing generally indicates a loose post and hence an unsafe deck, according to a study by a consortium including the American Society of Home Inspectors. About 85 per cent of U.S. homes have a deck or balcony, and 20 million of these may need repair or rebuilding, the report noted. If your deck has loose posts, you can tightly connect them up to code so they will withstand a 90.7kg. force applied in any direction, according to engineering professor Joseph R. Loferski of the Department of Wood Science and Forest Products at Virginia Tech.
Hold the loose deck post in place with pipe clamps.
Remove existing lag screws or lag bolts.
Hold a steel connector in place, its long leg oriented horizontally along the joist nearest the post, so that its centre line falls 2 inches below the top of the joist and its short leg touches the rim joist inside of the centre line of the post.
Mark the centres of the three holes in the steel connector with Xs. Drill through the joist, the rim joist and the post.
Insert lag bolts through the joist and tighten the washers and bolts with a socket wrench. Insert a lag bolt through the post and the rim joist and tighten its washers and bolts.
Add a second steel connector below the first to further reinforce the deck post, particularly if there is a risk of a severe challenge to the deck railing, from, for example, a falling tree or large group of people.
Other means of reinforcing a loose deck post, including additional lag screws and lag bolts on their own, are not adequate, according to Virginia Tech's Loferski.