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Guardrail Post (18)

When a 200 pound code specified load is applied to the top of a guardrail post, the effects can be quite dramatic. If the posts are bolted to the outside of the deck, the torque that the posts impose on the edge of an inadequately reinforced deck is easily enough to pull the outside rim joist right off. In other words, it's not enough to simply make sure you've done a good job bolting the posts to the side of the deck. It's also important to reinforce the the deck so it can resist post torque.

One way to beef up the deck framing is to lag bolt solid blocking inside the deck's rim joist on either side of the posts. Properly installed blocking transfers the torque of the posts back into the deck framing and keeps the rim joist intact. Keeping your post spacing under 5 feet and installing solid blocking will ensure the posts aren't going anywhere. (Alternatively, well placed metal plates will do the same job and are easier to install.)

One of the hallmarks of well built decks is the detail that goes into finishing the posts and railing parts. Even though you've done a great job reinforcing the posts, most people won't be able to appreciate your effort. If you want to build a deck that is not only strong but gets you those kudos you well deserve, take the time to encase your treated posts with 1x rough sawn cedar boards trimmed out with decorative bands in a pattern of your choice.

For longevity, always make sure to prime the back side of the cedar before it goes up and always, always paint or stain the cut ends. This simple precaution will keep water from wicking up into the cedar. Trapped moisture is the main reason paint and heavy stain peel. Combine proper sealing with making sure to provide a 1/4" gap off the top of the decking and your cedar trim will stay looking great for a long time.

Check out the section on Railings & Stairs to learn more about building guardrails that are not only really strong but look good too.