You are reviewing a roof package and need to know what a truss does. A roof truss is an engineered structural framework that carries the specified roof loads to its supports. The metal-plate-connected wood trusses used in residential framing combine wood members and connector plates into a designed component. SBCA terminology
The story behind the Cercha name explains the Spanish word. This guide explains the residential roof component.
What makes a roof truss a truss
A wood truss has outer members called top chords and bottom chords, plus internal web members. Their connections create a framework that commonly uses triangles. Its design sets the member sizes, connections, loads, and support conditions for the intended application. Metal-plate-connected wood truss definition
A truss is one structural component of the roof. The roof package also needs the building’s support, connections, sheathing, and stabilization arrangements. SBCA distinguishes individual truss design from responsibility for the complete building structural system. Delegated design roles
For identifying the pieces, read parts of a roof truss. Name the affected chord, web, connector, or bearing when reporting a field problem.
A truss shape alone does not establish capacity. SBCA explains that span, load, and spacing determine the chord sizes and web configuration. Two trusses can look alike and still have different designs. Truss configurations
How a truss differs from rafter framing
In rafter framing, the crew assembles rafters and the other structural members required by the building design. Each manufactured truss has its own designed members and connections. Compare the systems using the building design. Roof appearance alone does not settle the choice. Component definitions and design process Truss design coordination Rafter-framing members
Use this table to compare options with your designer and supplier. It does not show that either system always costs less or installs faster.
Scroll to read all columns.
| Question | Truss package discussion | Rafter-framing discussion |
|---|---|---|
| Room geometry | Which component profiles preserve the intended ceiling and attic space? | Which designed framing arrangement creates those spaces? |
| Supports | What bearings and reactions are shown? | What supports and connections does the building design require? |
| Services | Which routes and openings are planned? | Which permitted openings and routes fit the design? |
| Supply | Who designs, manufactures, and delivers the components? | Who supplies and installs the specified framing? |
| Changes | Which designer or manufacturer reviews a changed component? | Who reviews a change to the field-built structure? |
Do not generalize about price, clear spans, or construction duration without a project quote and design. Ask for the same roof geometry, loads, finishes, and scope in each comparison.
Who designs and builds the trusses
SBCA describes separate roles in the delegated design process. The building designer owns the building structural system. The manufacturer reviews construction documents and communicates design parameters. The truss designer designs the individual trusses and prepares their drawings. Design responsibilities
The individual truss designer does not automatically design the entire roof or floor system. Give the manufacturer the complete design requirements. Have the building designer review supports, connections to other work, and the larger structure. Limits of individual component design
The Truss Plate Institute establishes design, construction, quality-assurance, and testing methods for metal-plate-connected wood trusses. Its standards page identifies ANSI/TPI 1 among the industry’s design standards. Check the project documents for the applicable standard and edition. The newest publication does not necessarily govern your permit. TPI standards development
Manufacturers and suppliers can provide component layout and estimating support. Builders FirstSource describes roof-truss and engineered-wood design services as one supplier example. Confirm delivery coverage and stock separately. The service description does not show a relationship with Cercha. Supplier design services
Use the trusses and engineered-wood supplier page to prepare the supplier conversation. Check which design work the quote includes.
What belongs in the roof package
Ask for the current truss submittals. Confirm which documents accompany fabrication and delivery. Keep individual truss drawings, component locations, connections, accepted changes, and installation guidance available to the framing lead.
SBCA’s jobsite packages provide information on handling, storage, installation, restraint, bracing, and jobsite safety. Use that guidance with the project-specific design documents. A placement diagram shows where trusses go. Give the crew installation instructions too. SBCA jobsite packages
Before releasing the package for production, ask:
- Does the supplier have the current approved roof and floor geometry?
- Are bearing locations and required loads coordinated with the building designer?
- Are attic use, ceiling profiles, and mechanical routes defined?
- Who reviews the submittal and accepts revisions?
- Which connection and bracing documents reach the crew?
- What is included in delivery, unloading, and installation?
Use order roof trusses to turn those answers into a release packet. Keep unresolved design changes out of the fabrication release.
Shape affects the space under the roof
Pitched and parallel-chord trusses are basic configuration families. Other profiles accommodate vaulted ceilings, attic rooms, hip roofs, and other geometry. SBCA’s configuration resource shows these variations; the component designer determines the arrangement for the required application. Configuration examples
Do not infer usable storage from an open-looking roof cavity. Ask which loads and intended use are included in the design. Space for insulation or services does not mean the floor is approved for storage or occupancy.
Use roof truss types to distinguish the roof profile, web pattern, and structural role. A girder describes what the component supports, while a scissor configuration addresses the interior profile. Use each label for the part of the design it describes. Girder terminology Profile examples
Plan installation and get changes reviewed
Assign the framing crew the receiving, lifting, and installation scope before delivery. Use the truss-order guide to record that handoff.
Trusses need handling, temporary stabilization, and permanent integration into the building. SBCA’s BCSI guide addresses those subjects. Give the crew the documents and assign responsibilities before lifting trusses. BCSI guide
SBCA warns about components damaged by poor storage, mishandling, and undocumented cutting or drilling. Its field-practices article directs installers to consult the building designer or manufacturer before modifications. Do not cut a web for a duct and plan to ask later. Field alteration and handling risks
If the crew finds damage or a layout conflict, identify the component mark and location. Send a wide photo, close-ups, the relevant drawing, and the proposed change to the responsible contact. Keep the issue open until you have an accepted written solution.
Keep the repair details with the installed component’s records. Ask the framer to identify any later changes during the inspection-readiness walk. Use framing inspection to coordinate the building and rough-trade approvals before insulation.
What to ask before accepting a quote
Ask for the design basis and full scope along with the package price. Identify the manufacturer, design review owner, current revision, delivery conditions, and field-question contact. Confirm whether installation and other framing materials are included or separate.
Give the supplier the actual project address and required schedule. Ask the supplier to quote that package and schedule. Confirm lead time and capacity directly with the supplier.
Where Cercha fits
Cercha supplier profiles show carried brands, and Search helps you find relevant trades and suppliers by location. Portfolios and Messages support the first conversation about the roof package. Keep component design, production release, and installation acceptance with the responsible professionals.