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Deck Framing Gone Wild

Decks, Decks, Decks, Framing June 25, 2009 admin


 

To hear our esteemed editor describe it, procrastination is not a virtue. But when it comes to deck building, putting some things off can come in quite handy. For example, you really don’t need to decide on the exact size of your deck until things get under way.

Sure, you should have a pretty good idea of the basic size of the deck, whether or not there will be multiple levels and how you will get from one level to the next. But to get started you don’t need to have precision right down to the inch.

 

To get the full benefit of your mad procrastination skills in deck building, you need to use cantilevers, which are horizontal construction components that extend beyond their outmost vertical supports. In general, cantilevers should not extend more than 1/3 of the span rating. For example, if your beams can span 48 inches, you can cantilever out 16 inches beyond the last post.

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The cantilever allows you to use imprecise layouts for the footings and blocks of the post and beam system. It also means the beam spacing and the ending points of your joists do not need to be dialed in either. Another big advantage of the cantilever is that you can hide footings, block and post back under the deck and they won’t interfere with trim or skirting.

When I lay out the blocks for a post-and-beam floor system, whether it’s for a shed or a deck, I purposefully put the rows of blocks about one foot inside the finished structure in both directions. I reach the outside of the deck with cantilevered beams in one direction and cantilevered joists in the other direction.

One of the big advantages to this system of cantilevering is that the blocks do not need to be laid out precisely, other than just being in line with the beams. So the post and beam layout can be relatively square, and then as the joists get put in position they can be aligned and squared more precisely.

In addition to the concept of cantilever, is the idea of running material wild until you make your final cut. “Let it run wild” is a construction expression that simply means to leave a little extra material hanging out there to be cut off later. You don’t have to make the final decision on the exact deck dimensions until you see how everything is coming together. You can trim beams when you are done with the joist layout. You can trim joists when the deck boards are nearly completed and you can trim deck boards after they are installed. Chalk lines and saw guides help make straight cuts on the ends of the beams, the joists and the deck boards.