If you plan on building your own floor or deck, you will need to use joist hangers to increase the amount of weight your project can support. Joist hangers are pieces of metal used to connect outer ledger beams to the parallel boards that support your floor or deck. However, if you must install joist hangers, you should consider selecting adjustable ones. Adjustable joist hangers can allow your joists to be adjusted up and down after they are attached, unlike standard joist hangers that are one piece, and permanent. What follows should give you everything you need to know about installing adjustable joist hangers.
Step 1 - Measurement
The first step to installing an adjustable joist hanger is figuring out exactly where to put it. While your joist hanger is adjustable, precise measurements are important. Start from the corner of your ledger board and measure it out in 16 inch intervals. Mark each spot with your pencil.
If you will be installing adjustable joist hangers on multiple ledger boards, you can save yourself a lot of time by doing your measurements on a piece of scrap lumber and using it to quickly find the measurements for all of your ledger boards one at a time.
Step 2 - Placement
Once you have measured and marked your ledger board or boards, place a joist hanger at one of the spots you have marked. Line up the top of the joist hanger with the top of the ledger board—do not rely on the adjustability of the joist hanger. Hold the adjustable joist hanger tightly so it is placed firmly against the ledger board.
If your adjustable joist hanger has speed prongs—small attached fasteners for temporary holding while you nail—hammer them in now. Obviously, this is not enough to hold your adjustable joist hanger, but it will make the next step easier.
Step 3 - Nails
Choose the nails you use for your project carefully, as they can have many important effects on the quality of your work. If you are working on an outdoor project, such as a deck, use hot-dipped galvanized nails. For floors or any other indoor projects, use common nails. Whichever type of nails you use, be sure to use the largest ones that are acceptable to use with your particular adjustable joist hangers. The most common type use 16d nails, but this may vary.
Attach your joist hanger to your ledger board with your hammer and carefully selected nails. Use a nail on every nail hole or your adjustable joist hanger will not be as strong as it can possibly be.
Step 4 - Joist
Now you are ready to actually attach your joist. Insert the joist into the joist hanger, making sure it is placed correctly and tightly. Use short nails—1 1/2 inch ones are best—as you do not want them to go all the way through your joist.
If need be, now or later, you can adjust your joist up and down by using the screw mechanism.