A joist hanger is a metal bracket that attaches to the structural beams of a building. One end of a joist, the horizontal pieces of lumber that support the floors, slides into the bracket. Floor joists can be 2x6, 2x8, or 2x12, depending on the amount of weight they will support. Hanging joists supporting the floor of a structure requires two joist hangers per board. Once properly installed, each joist fits snugly into place and is secured by wood screws. This how-to will walk you through hanging the joist, including the proper placement of the joist hanger that precedes it.
Step 1 - Cut the Joists to Length
Measure the distance the floor joist(s) must span from one beam or rim to the other. With your tape measure and a pencil, mark off the length each joist should be. Err to the longer so you don’t end up with a joist that is too short. With the circular saw, cut each joist to the proper length.
Step 2 - Set the Joist Hanger
For most residential applications, the joist hangers you will use do not have a flange or L-shaped edge on top to keep them in position on the beam. Instead, they have small spikes on the rear side. That means they have to be fixed in the right position on the side of the beams so the top of the joist is flush with the beam. 2x6 joists require 2x6 joist hangers, and likewise. Using a scrap piece of 2x6, hold it in place in a joist hanger as if it were attached. Hold the top edge flush to the beam to determine the exact placement of the joist hanger and mark the bottom edge on the beam with a pencil.
Step 3 - Space the Joist Hangers
Each joist should be spaced 16 inches on center. That means that from the center of one joist to the center of the next there should be a distance of 16 inches. Take the measurements and make marks across the whole area into which the floor joists will be installed. This will save you time when you are ready to hang them. You will attach each joist hanger with the mark centered while at the same time making sure it is the appropriate distance from the top.
Step 4 - Attach the Joist Hangers
Using tico nails, which are made for sheer weight support, attach each joist hanger in the right spot. Use six nails per joist hanger. There are holes made in them just for this purpose.
Step 5 - Set the Joist
Once joist hangers are attached for both ends of the joist, set the floor joist in the brackets. If you measured correctly, it should fit perfectly. There are holes in the side of the hangers to drive tico nails at 45 degrees into the joist. Squeeze the bracket against the floor joist and drive the first nail. Follow this with three others per end of each joist. The floor joist should be flush to the beam and perfectly secure at both ends.
With the joist hangers in place, the joists are easily installed. Again, make sure they are flush with the beam. Do not use 16d nails, for they are not designed for sheer (downward) weight.