Floor Joist and its benefits, drawbacks, and various types

The floor joist is an open structural member which is horizontally placed between beams and carries the load of the building for the next set of structural members, which may be vertical. It is these joists that carry the weight of the walls, furniture, appliances, and even people inside a room, as they are part of the floor system, which is what keeps the room at its proper temperature.

In a structure, floor joists play an important role in spreading out the load. The condition of tension is the state in which wood fibers on the bottom of the joist go when weight is applied to the floor and the joist. This causes the top fibers to compress, thereby distributing the load evenly throughout the fibers.

Objectives of Pedestals

Here are a few of the objectives of Pedestals:-

Various Components of a floor frame

Having stable and durable flooring is one of the most crucial parts of constructing any kind of building. Before constructing the framework of the floor, it's better to make sure that the foundation of that particular structure is well established and sturdy. Below mentioned a few comprehensive lists of various components of the floor frame:-

Blocking materials: There is a technique called bridging, which consists of small wood sections that are fastened together between joists. As a result, there is a level of stability along the lateral axis.

Header joists: An opening in the floor is framed with a header, or rim joist, which is used to support the floor. Stability on the side is provided by it. An opening in the floor is framed with a header, or rim joist, which is used to support the floor. Stability on the side is provided by it.

Floor Joists: The floor joists are large pieces of wood that are located on the narrow ends of the floor and are used to frame the floor and make up the framework for the floor. One of the feet is attached to the sill plate by an evenly spaced flange that is incorporated into the sill plate.

This joist system is connected to a subfloor, which carries the weight of the loads that will be carried by the subfloor to the walls so that they can be supported by the walls.

Supported Beam Structure: Alternatively, it would be possible to use a support beam, which is also called a center beam, to support the first-floor joists, if they are too short to reach between the foundation walls and the first floor.

Various Kinds of Floor Joists

Below mentioned are a few kinds of floor Joists:-

Solid Lumber Joists type

Typically, solid lumber joists are made of contagious wood that comes from trees that are older than 100 years old. There are many factors that can affect their span distances, which include species, board sizes, spacing, deflections, and so on. It is still quite common on job sites to find Solid Lumber joists which are installed, but there are only a limited number of trees that can be used for these joists, and using younger trees could result in warped boards.

Benefits of using Solid Lumber Joists

1. They are more likely to survive a fire if they are made from this type of wood.
2. In terms of cost efficiency, lumber joists cannot compete with other engineering solutions.

Drawbacks of using Solid Lumber Joists

1. There is not much of an environmental benefit to these types of floor joists.
2. A limited distance can be covered by these types of floor joists.

I-Joists type

There is another term called TJI joists, which describes I-joists, which is a type of joist that looks like a small "I", hence their name. Depending on the section of the I that you are looking at, there will be a different type of material used. There are two main types of joists, bottom, and top, in which you will find wood or a laminated veneer on the bottom part and plywood in the center part of these types of joists, typically built with wood or a laminated veneer.

Benefits of using I-Joists

1. Have a much longer span as compared to solid wood.
2. These kinds of joists usually are way lighter in weight, which as a result makes them easier to maneuver.

To learn more, watch the following video tutorial.

Video Source: Kens Karpentry

Drawbacks of using I-Joists

1. These kinds of floor Joists are not much resistant to fire.
2. These kinds of floor Joists are highly costly.

Open-Web Floor Trusses joists type

Wood pieces are cantilevered in this kind of floor joist to assist in supporting floor loads. Due to their simplicity, these trusses are preferred by many builders because no holes are required for pipes or electrical wiring.

Benefits of using open-web floor trusses

1. Compared to I-joists, these types of floor joists were found to have a more durable construction.
2. The durability of these joists is much greater than that of other types.
3. As a result of having these types of joists, you can easily adjust or install any type of electrical appliance without any problems.

Drawbacks of using open-web floor trusses

1. No trimming is allowed because these joists have specific lengths.
2. Relatively costly.


During the construction of a room, the floor joists have to lift the weight of the floor and all the items that are in it. There are factors that need to be taken into consideration when choosing floor joists for your home like material, size, etc. While span tables and calculators exist to help determine the exact dimensions of joists needed, a structural engineer should determine the exact specifications of joists required in accordance with the building's engineering and local building regulations.

Floor Joist and its benefits, drawbacks, and various types