Can I cut the web members to fit a large duct?

No. Web members are structural. Cutting them compromises the truss and requires engineered repairs.

How do I handle site modifications?

Any modification requires written approval and a sealed repair detail from the truss design engineer.

Do these trusses shrink like solid lumber?

Open-web trusses exhibit significantly less shrinkage because the chords are composed of kiln-dried lumber and the depth is constant.

What is the typical lead time?

Lead times typically range from 4 to 8 weeks depending on factory backlog and complexity.

Open-Web Floor Trusses

Trusses

Floor

As of early 2026, pricing typically ranges from $4.50 to $8.00 per linear foot, depending on depth, span, and complexity of the layout. Prices are subject to regional lumber indices and project-specific engineering costs.

Open-Web Floor Trusses (2026)

Prepared by Lumberama's Building Materials Team

|Last updated September 3, 2026|Sources & methodology

Open-web floor trusses are structural building components consisting of top and bottom chords connected by a web of diagonal and vertical members. Unlike solid-sawn joists or I-joists, the open-web design creates a large void space, which is primarily utilized for the integrated routing of mechanical, electrical, and plumbing (MEP) systems.

Key Features

Large open voids for plumbing
HVAC ductwork
and electrical wiring. - Long-span capabilities without intermediate load-bearing supports. - Precision engineering via software-calculated load distribution. - Consistent depth across entire span to prevent crown-related issues. - Dimensional stability resisting shrinkage and warping common in solid lumber.

Specifications

Chord dimensions: Typically 2x4 or 2x6 kiln-dried stress-rated lumber. - Web configuration: V-shape or W-shape patterns depending on load requirements. - Truss depths: Common depths range from 12 inches to 24 inches. - Max Spans: Up to 30 feet depending on depth

spacing

and loading criteria. - Connections: Pressed-in galvanized steel connector plates.

Applications

Residential floor systems for multi-story homes. - Commercial flooring applications requiring unobstructed ceiling plenums. - Retrofit projects involving significant MEP upgrades in tight spaces. - Buildings requiring open floor plans with minimal column interference.

Installation Overview

- Trusses must be installed according to the sealed engineering drawings provided with the order. - Maintain proper orientation as indicated by the manufacturer's mark. - Ensure temporary and permanent bracing is installed as specified in the engineered layout. - Trusses are typically set using a crane or boom truck. - Do not field-cut, drill, or notch chords without explicit written approval from the design engineer.

Pros & Cons

Pros

✓ Reduces labor time for MEP trades. - Spans longer distances than standard dimensional lumber. - Factory-controlled environment ensures consistent structural integrity. - Eliminates the need for bulkheads or dropped ceilings for ductwork.

Cons

✗ Requires longer lead times for custom design and manufacturing. - Higher upfront material cost per foot compared to I-joists or solid lumber. - Heavy weight requires mechanical lifting equipment for installation. - Sensitive to field alterations; any deviation from plans requires structural review.

Code Requirements

- Must be designed and manufactured in accordance with ANSI/TPI 1 (National Design Standard for Metal Plate Connected Wood Truss Construction). - Projects require sealed engineered drawings from a licensed professional engineer in the state of installation. - Many local codes require specific fire-rated blocking or specific ceiling finishes (e.g., 5/8" Type X gypsum) for unprotected truss assemblies.

Buying Tips

- Verify structural loads (live and dead) with the project engineer before ordering. - Account for 4-6 week lead times for engineering, manufacturing, and delivery. - Request "sealed prints" early to secure building permits. - Confirm MEP duct sizes to ensure they fit within the truss openings before final sign-off.