Floor Joist Cross Bracing

Published on:
Last Update:

Whether you’re undertaking floor framing for your new home or are considering a floor renovation project- factoring in cross-bracing may be important.

Cross braces boost your floor’s structural integrity, which we go into detail in the next section. This blog article also details the proper process for bracing floor joists, as well as the recommended distance between joist bridging.

Do floor joists need cross bracing?

If you live in an older home that’s over 50 years old, the floor probably bounces and squeaks a lot when you walk on it. This would be because the joists underneath probably lack any additional, lateral support.

Such support comes in the form of wooden blocking, or the more popular cross-bracing. Therefore, renovating the floor framing by installing cross braces will serve to keep the joists rigid, thus minimizing floor bouncing and squeaking.

For a new home, you’ll want to install cross braces during the construction of the floor frame, to avoid the aforementioned floor problem in futures. Basically, cross-bracing your floor joists makes your wood frame floor system stiffer, consequently preventing twisting, deflection, squeaking, sagging, and bouncing.

What’s more, cross-bracing is usually a building code requirement in various states. These guidelines usually necessitate the installation of cross braces in residential developments where the floor joists exceed two-inches by 12-inches.

How do you brace floor joists?

You don’t have to dig into your pockets to effectively brace your floor joists, as even with basic woodwork skills, you can successfully undertake this task as a DIY project. To properly install diagonal bracing in between your floor joists, we recommend following the procedure detailed below:

Step 1: Observe safety measures

The first step in any construction-related project should always be to undertake safety measures by wearing the appropriate protective gear- including a helmet, eye goggles, and hand gloves.

Step 2: Identify installation spots

Second- establish the exact installation spots for the cross braces, while marking the same on the two parallel joists using a pencil and measuring the distance between the opposing ends.

You’ll need a tape measure for this step as cross braces are usually installed diagonally, with one end attached to the lower end of a joist and the other end fastened to the upper end of the parallel joist.

Step 3: Cut out pieces

Next, make your pair of diagonal braces by cutting out pieces of lumber that are six-inches long, two inches wide, and three inches deep. Then, cut one end at an angle of 45-degrees. This is usually done using a builder’s square and the reason is to ensure a smooth fit once cross braces are installed diagonally.

Step 4: Cut the 45 degree edges

Now, for the opposite end, you’ll have to refer to the diagonal dimensions you established in step two above, before similarly cutting that end at a 45-degree angle as well.

Step 5: Install and fasten the floor braces

After making both of your braces using the methods detailed in the previous two steps, install the braces by fastening them diagonally to the parallel floor joists. One edge of the 45-degree end points should contact the sub-floor, with the similarly longer edge on the opposite end contacting the bottom edge of the opposing/parallel joist.

Repeat steps two-five above for all parallel floor joists until you’ve adequately cross-braced the entire floor frame.

How to Stiffen a Floor with Bridging

While the terms cross-bracing and bridging are often used interchangeably, the key differentiating factor is that bridging typically entails the use of metallic support pieces.

Meanwhile, cross braces- as described earlier- are typically made from cut-out pieces of lumber. If your floor is bouncy due to lack of prior installation of floor joist support, you can rectify this mistake by installing metal bridging that will stiffen the floor.

The proper process for installing metal bridging is described below:

  1. Purchase your preferred type o metal bridging from your local lumber yard, and wear the appropriate construction safety equipment.
  2. First off, you’ll want to tighten up the fastening that has loosened up on the old bridging. You can hammer in more nails if necessary.
  3. Next, using a tape measure, establish the span of your joists. This is the distance between any two beams or columns that support the floor joists. Then, divide this distance by three to determine the one-third point where you should add your bridging material.
  4. Next, fasten the metal braces diagonally onto the floor joists. You can install two rows of bridging for enhanced floor reinforcement.

Can You Make a Brace between Floor Joists

Yes, you can make easily make a brace between floor joists by following the procedures detailed in the preceding sections. It’s a simple process that doesn’t have to be contracted out to an expert. If you’re a DIY enthusiast, you’ll find this project quite exciting, while still saving yourself some money. Remember, however, that attention to detail is important for successful installation, which is why you’ll want to get your measurements right.

How far apart should joist bridging be?

As earlier mentioned, your metal braces for bridging should be placed at one-third intervals within the span of your floor joists. Therefore, for floor joists that are centered 12-inches apart, you’ll want to install bridging at the four-inch and eight-inch mark. Note, however, that most commercially-available metal bridging products are designed to fit floor joists that span 16-inches or 24-inches.

Finally, it’s crucial to note that bridging isn’t recommended for every type of flooring. Therefore, if your joists are made of commercial wood and you still wish t give it additional support, you might want to reach out to a woodframe flooring expert for further guidance.

Photo of author


Joe McGuinty
I’ve been working with floors for over 12 years. I started as a flooring contractor, primarily in materials selection. Then, I switched careers into accounting, so my wife and I began buying, renovating, and re-selling homes on the side. You’d be surprised how much value you can add to a home simply by adding new floors.

1 thought on “Floor Joist Cross Bracing”

  1. Therefore, for floor joists that are centered 12-inches apart, you’ll want to install bridging at the four-inch and eight-inch mark.

    I think you mean 12 foot span and install


Leave a Comment