Installing a Floor Joist

If you want to have a solid, reliable floor, and you plan to do your own installation, an important part of the process will be making sure that every floor joist is installed correctly. Your joists, or horizontal cross pieces to your floor's frame, are very important to your floor, and their reliability will dictate the overall effectiveness of your installation. While installing joists does require some precision, doing it correctly is not out of reach of the average homeowner.

Step 1 - Preparing the Floor

If you are working with an already installed floor, you will need to pry up the existing floorboards. If you are doing this to replace damaged joists, you will need to remove them first. Use a saw to cut out and lift away as much of the joist as possible, then use your hammer to remove the nails from the joist hangers and remove them as well.

Step 2 - Planning and Measuring

Before you install anything, you will need to choose a spot to install your joist. As joists should be placed roughly 16 inches apart, the number and placement of your joists will depend on the length of your floor. Once you figure out an appropriate number and distance for your joists, take accurate measurements on both beams. Mark both spots on both beams where you will be installing your joist hangers with a pencil.

Step 3 - Installing Joist Hangers

While it is possible to install a joist without using joist hangers, it is not a very good idea. Joist hangers will make a much stronger connection than nails on their own and help to make sure that the joist is placed properly as well.

Get out one of your joist hangers and select a beam to attach it to. Center it on one of the marks you have made, and nail it into place. Use all nail holes to secure your joist hanger at the proper spot.

You may want to use either a joist or a piece of scrap material as a mockup to check your measurements at every step. This significantly reduces the chance that you will make a small error that requires you to start over completely several steps down the road.

Repeat the process for the joist hanger on the opposite side. Test it out with your joist as often as you feel is necessary to make sure that your setup will work in the end.

Step 4 - Installing the Joist

Once you have your hangers nailed to your beams and you are sure that they are located in exactly the correct spots, you can install your joist. Make sure it fits snugly, and insert it into the two joist hangers simultaneously. Finish up by nailing the joist to the joist hangers using the appropriate nail slots.

Step 5 - Finishing Up

Repeat the process as many times as necessary to have joists at 16-inch intervals underneath your floor. Once you have done this, you can replace or install your floorboards normally, confident that you can rely on your joists to hold your floor together.