To this point our approach to deck design has concentrated on the abstract and immaterial. But as we advance closer to a working plan we will need to consider how our ideas are translated into real space in respect to the laws of physics and materials available for construction. We don’t want to become overly concerned with logistics, just aware that they exist.

For instance it may not be effective to build a deck projecting 16’-6" out from the house. Standard 2x10 deck framing installed at 16" on center will only support a maximum joist length of 15’-10"; that means you will need to add a second beam and another row of posts to extend the deck just 5" more. Also lumber is only sold at specific lengths (8’,10’,12’,14’,16’,18’,20’) a 16’-3" joist will require you to waste 1’-9" of material for each joist. The added cost of materials, time spent in labor, and visual imposition of extra posts will certainly outweigh anything you would gain from an extra 6" of depth. A better solution would be to reduce the deck depth to an even 16’ or extend your deck to a full 18’ to make more efficient use of materials. Different types of wood have different design limits to consider, you may want to consult a joist and beam span chart.