A Detailed Guide to Floor Trusses

Choosing the right floor system is crucial for any construction project. It impacts how functional and how flexible a building design is. Among the many available options, floor trusses stand out as the superior solution. The system of horizontal structural members offer a unique mix of strength, flexibility, and efficiency.

This guide explores floor trusses, covering their definition, types, and benefits. It explains exactly what these engineered wood products are, and go through their many advantages.

For questions about the use of engineered trusses for your floor, please contact our expert team at Pacific Truss. We are here to assist you at every stage of the process.

Understanding Their Purpose and Design

Our design engineers create floor truss systems from dimensional lumber, joining them together with metal plates. Unlike conventional floor framing, they offer superior load bearing capabilities. This allows the design to include long spans between load bearing walls.

In simple terms, longer floor joist spans are the distance between two support points in construction. Greater spans mean more stress and force, so proper design is crucial to support live loads. This capacity is calculated by our expert engineering team using span tables.

One way to optimize construction costs and maximize functional space in a building is by reducing the number of beams or load-bearing wall supports. This not only reduces material and labour expenses but also creates opportunities for creative design concepts.

On the other hand, extending the joist span increases the distance between supports, creating larger, unobstructed rooms below. This adjustment can improve the visual appeal and utility of areas like living rooms and commercial spaces.

There are three types of floor joists:

1. Dimensional Standard Lumber: Available in sizes like 2×10 and 2×12 purchased at lumber yards. While cost effective, they have shorter spans and tend to be bouncy.
2. Engineered I-Joists: Available at Pacific Truss, these have better span lengths than dimensional lumber. However, they are less versatile for mechanical trades.
3. Floor Trusses: Considered the superior option, these trusses are open-web design structures resembling joists. Floor trusses provide longer spans and customization for specific mechanical needs such as heat ducts. They also offer superior fire performance compared to I-Joists.

Distinguishing Features of Floor Trusses

• Fewer Layout Restrictions: The depths may vary from 12 inches to 24 inches deep. A deeper truss can reduce the need for additional supporting structures.
• Design Opportunities: Our team can easily incorporate heating and cooling openings into your floor truss design.
• Improved Diaphragm Effectiveness: Wider widths make it easier to attach to subfloors. This helps avoid having squeaky floors in your home.
• Removal of Rim Boards: In some situations, you can eliminate the need for full-height rim boards. This change simplifies construction and reduces costs.
• Concealment of Beams: Custom designed trusses can conceal beams within the structure, simplifying wiring, plumbing, and mechanical installations. However, this is feasible only with deeper trusses as a double top chord is still necessary for this purpose.
• Enhanced Vibration Resistance: Floor trusses in construction projects provide improved vibration resistance, especially in spaces like apartments or offices. Adding heavy dead loads such as concrete toppings, improves stability and comfort, enhancing structural integrity and satisfaction.
• Reduced Shrinkage: The use of multi-directional lumber minimizes warping and shrinkage compared to traditional lumber floors.
• Enhanced Safety: Wider floor trusses with improved stability are easier to install, reducing the chances of accidents and delays. They can easily accommodate special features like 2-inch drops for shower areas.

The Benefits of Building with Floor Trusses:

• Simplified Installation: Pre-assembled trusses make construction easier, saving time and labor costs. They are manufactured to the correct length and numbered to match the floor truss layout.
• Lightweight and Strong: Manufactured in controlled environments, floor trusses offer consistent strength and steadiness in construction. Here in British Columbia, Canada, we use SPF (spruce-pine-fir) wood for our trusses, whereas it is more common to build with southern yellow pine in the USA.
• Design flexibility to accommodate mechanical openings.
• The ability to include longer spans with higher load capabilities provide design flexibility for residential and commercial construction.
• Reduced construction costs with overall savings in labour, time, and materials.
• At Pacific Truss, our Cobble Hill facility provides extensive quality control measures. All our engineered wood components meet and surpass Industry Association and building codes requirements.
• Convenient for various trades like plumbing, heating, and electrical work.

Understanding the benefits of using floor trusses will allow you to make the best choices for your project’s needs. Whether building, expanding, or renovating, consider using floor trusses as a modern solution in structural support.

Reach out to Pacific Truss today to explore how we can bring your vision to life. We have worked on projects of every size and style, and look forward to working with you.