How Far Can Floor Trusses Span Without Support?

Are you planning to build or renovate your house and wondering how far your floor trusses can span without support? In this article, we’ll delve into the topic of floor trusses and explore their limitations and potential.

Floor trusses are structural elements that transfer weight from the flooring to the walls or foundation of a building. They have become a popular alternative to traditional joists because of their many advantages, including superior strength, durability, and versatility.

One of the critical factors to consider when designing a residential or commercial building that uses floor trusses is the span. Keep reading to learn about the factors that influence the span of floor trusses, and their maximum span capabilities.

Factors that Influence the Span of Floor Trusses

Floor trusses come in various sizes and shapes, and their span capabilities will depend on several elements. Let’s look at some of the influencing factors:

1. Truss Depth

The depth of the truss is a crucial aspect that determines its span capabilities. The deeper the truss, the longer its span. Trusses with greater depth can support more weight without bending or sagging, which makes them ideal for larger rooms or open-plan spaces.

2. Truss Spacing

The spacing between trusses also affects their span capabilities. The wider the spacing, the longer the span between trusses. However, wider spacing requires more massive trusses to support the same weight, which can add to the cost of construction.

3. Truss Type

There are various truss types, including flat, pitched, and arched trusses. Each type has its span capabilities and will depend on the factors mentioned above.

4. Loads on the Trusses

The weight of the flooring, walls, and anything else supported by the trusses also affects their span capabilities. The more weight, the shorter the span.

Maximum Span Capabilities of Floor Trusses

The maximum span capabilities of floor trusses will depend on several factors, including the ones mentioned above. Let’s look at the general maximum span for different truss depths, spacing, and loads.

1. Truss Depth

For 24-inch deep floor trusses, the maximum span is 32 feet. For 30-inch deep trusses, it is 36 feet. For 36-inch deep trusses, it is 40 feet. And for 48-inch deep trusses, the maximum span is 50 feet.

2. Truss Spacing

For 24-inch on-center spacing, the maximum span for 24-inch trusses is 18 feet. For 30-inch trusses, it is 22 feet, and for 36-inch trusses, it is 26 feet. For 48-inch trusses, the maximum span is 30 feet.

For 16-inch on-center spacing, the maximum span for 24-inch trusses is 22 feet. For 30-inch trusses, it is 25 feet, and for 36-inch trusses, it is 29 feet. For 48-inch trusses, the maximum span is 35 feet.

3. Loads on the Trusses

The maximum span for a uniformly distributed load of 40 pounds per square foot (psf) for a 24-inch-deep truss with 24-inch on-center spacing is 14 feet. For a 30-inch-deep truss, it is 17 feet, and for a 36-inch-deep truss, it is 19 feet. For a 48-inch-deep truss, the maximum span for a 40 psf load is 24 feet.

For a 60 psf load, the maximum span for a 24-inch-deep truss with 24-inch on-center spacing is 11 feet. For a 30-inch-deep truss, it is 14 feet, and for a 36-inch-deep truss, it is 16 feet. For a 48-inch-deep truss, the maximum span for a 60 psf load is 20 feet.

FAQs About Floor Trusses

1. Can floor trusses span over a garage?

Yes, floor trusses can span over a garage. The maximum span will depend on the factors explained earlier.

2. Can floor trusses support a second story?

Yes, floor trusses can support a second story, but the maximum span will depend on the height of the second story and the loads it will bear.

3. How long do floor trusses last?

Floor trusses can last for many years, depending on several factors, such as the quality of materials used, maintenance, and the environment surrounding the trusses.

4. Are floor trusses better than traditional joists?

Floor trusses are better than traditional joists because they are stronger, more durable, and more versatile. They can span longer distances without the need for support beams, making them ideal for open-plan spaces.

5. How much do floor trusses cost?

The cost of floor trusses will depend on the size, span, and complexity of the truss design, as well as the materials used. On average, floor trusses can cost anywhere from $1.50 to $4.50 per square foot.

6. Can floor trusses be customized to fit unique structural designs?

Yes, floor trusses can be customized to fit unique structural designs. manufacturers offer a range of flexible designs to fit the specific needs of your project.

Conclusion

In conclusion, floor trusses are essential structural elements that require careful consideration during the design process. They offer unique advantages over traditional joists, but their maximum span capabilities depend on various factors.

The span of floor trusses will impact their strength, durability, and overall performance. Understanding the factors that influence their span will enable you to make informed decisions that ensure their optimal performance.

If you need help designing, selecting, or installing floor trusses, consult a professional engineer or contractor to ensure your project meets your needs and meets all safety and building codes.