Learn joist span and reading a span chart 💪 #deck #joistspan #spanchart #learn #carpentry

Floor span explained. When joists are installed over two bearing points, we have to be sure that this joist can handle the span. The span is from both ends of bearing points. Both of these sections would be considered cantilever. In this case, the cantilever can only be 1/4 the length of the back span. When determining your span, you have to consider your joist spacing. Let's say these are 24 on center. That means these joists are going to have to be bigger than let's say if you did 16 on center. This distance from here to here is your beam span. Your beam is typically double or triple 2x material. It requires post to beam connection here and then a post to concrete connection here. This here allows for an inch of stand-off. So, when you install your post, you don't get rot in this bottom section. Also, where your joist meets your beam, you need to have hurricane ties. This helps resist uplift. This here is a span chart. You see here we have species, size, and spacing. The size has to do with the depth of the lumber. This is where your joist spacing comes to play. You could have 12 on center, 16, or 24. The further your spacing is on your joists, the less length you can go between your beams. So, if you do 12 in on center with a 2x10, you can go 18 ft. If you do 24 on center with a 2x6, you can only do 7 ft 7 in. So, with a 2x10, you can nearly do double of a 2x6. Joist beam span will look similar. It'll give you doubled or tripled and then go by the nominal size of the lumber. These spans for beams will be a lot less than the spans for your joist. These beams are required to hold the full weight of the deck. Joists are only required to hold a portion of the weight of the deck. If you want to remove this beam and are attaching to a house, you need to install a ledger. Ledgers are attached to the house with approved fasteners. There's a specified alternating pattern when you install ledgers. Depending on the height of your deck or if it has a ledger or not, you might require lateral bracing. Let's see what happens when a lateral force is applied to a deck. Don't forget, decks do fall over. Thanks for watching.