You need to name the parts on a truss drawing or report a field problem. Top chords and bottom chords form the outside edges, webs connect them internally, and connector plates join the wood members. Give the supplier the component mark and drawing location along with the part name. SBCA terminology
Identify the top and bottom chords
The top chord forms the upper edge of the truss. The bottom chord forms its lower edge and can be horizontal or pitched. Their appearance depends on the designed profile, so “bottom chord” does not always mean a level ceiling member. Chord definitions
Find the chords on your drawing before checking the webs. Trace the profile from one support to the other. Identify any change in slope or chord direction and match it to the approved component.
SBCA distinguishes pitched and parallel-chord configurations and illustrates many profiles. The drawing for your component determines its actual form and member arrangement. Use a roof-truss diagram to learn part names. Build from the actual component drawing. Configuration families
Read what is a roof truss if you first need to distinguish a supplied component from the complete roof system.
Locate webs, plates, bearings, and other parts
This original schematic identifies parts on one pitched profile. Its labels follow SBCA terminology. It is not to scale and gives no member sizes, plate sizes, connection details, loads, or bracing instructions. Use your component drawing for those requirements.
Use this table as a text key beside the component drawing. The descriptions follow SBCA’s terminology. Check the design drawing for member sizes, fastening, and capacity. Industry terminology
Scroll to read all columns.
| Drawing term | Where to look | What it identifies |
|---|---|---|
| Top chord | Upper boundary | Upper member or connected members forming the profile |
| Bottom chord | Lower boundary | Lower member or connected members forming the profile |
| Web | Between the chords | Internal member connecting chord locations |
| Panel point | Connected intersections | Location where webs and chords meet and connect |
| Truss plate | Member connection | Metal connector transferring forces between wood members |
| Bearing | Support location | Structural support identified for the component |
| Heel height | Outside face of bearing | Vertical depth of the truss at that location |
| Overhang | Beyond an exterior support | Portion extending past the bearing |
When reporting a defect, pair the term with a location. For example, write “top chord near the left bearing of component T4.” Use the actual mark from your drawing in place of the example.
Do not use “the left side” without establishing the drawing orientation. Send a wide photo showing the location, then a close-up of the condition. Keep the mark and plan revision in the message.
Match the diagram to the supplied drawing
Start with the component mark and revision. Use the placement diagram to locate that mark in the building, then open its individual truss design drawing. SBCA distinguishes the location diagram from the drawing describing one component. Drawing definitions
Trace the chords, then match the webs and joints. Read the shown dimensions, bearings, plate information, restraint notes, and referenced details with the supplier. SBCA offers separate drawing-reading lessons on dimensions, parts, bearings, loads, and bracing. Drawing-reading overview
Give the framing lead the current package from ordering roof trusses. Record drawing conflicts before release or installation. A part name helps you ask a precise question; it does not authorize a change.
Read the webs and panel points
Web members connect the chords inside the truss. Panel points identify the connected intersections. A named web pattern describes an arrangement, but its sizes and geometry still depend on the designed loads, spacing, and span. Web and panel-point definitions Configuration selection
Ask the supplier to identify the relevant member or panel point on the design drawing. Do not decide that a web is redundant because another truss elsewhere in the house has a different pattern.
Plan service routes through the spaces between the webs. Ask the designer and manufacturer which routes fit the supplied arrangement. An opening on the drawing does not give you permission to cut a member to make it larger.
SBCA’s field-practices guidance warns about cutting, drilling, or modifying components without consultation. Use the planned route or obtain an accepted written change through the responsible contact. Field alteration guidance
See roof truss types for the difference between a web-pattern name and a ceiling-profile name. Use the right name when requesting a revised package.
Connector plates are part of the engineered component
Metal-plate-connected wood trusses use metal connector plates at the wood-member joints. SBCA’s definition includes the wood members and plates as parts of the engineered component. The design and manufacturing process set plate size, position, and member arrangement. Metal-plate-connected truss definition
TPI develops methods for design, construction, quality assurance, and testing of this component system. Its standards resource identifies the design standards used in the industry. Do not replace the supplied connection with a similar-looking hardware-store plate without an accepted detail. TPI standards development
If a plate appears displaced, damaged, or altered, record the condition and request review. Do not hammer, remove, add, or substitute connection material as an undocumented repair. Ask the responsible professional which repair is accepted.
Include the component mark with the photos. Show the joint and enough of the surrounding member to locate it on the drawing. Keep any accepted repair detail with the component records.
Heel height, bearing, and overhang are different dimensions
SBCA defines heel height as vertical truss depth at the outside face of bearing. It is not the overall height at the peak. Identify the measurement location before comparing two roof packages. Heel-height definition
The bearing identifies a support condition. The overhang extends beyond support. Check bearing and overhang separately from total profile length when laying out walls, eaves, and fascia. Ask the supplier to show the drawing dimensions instead of measuring a catalog illustration. Support and profile terminology
Review these dimensions with the designer and supplier:
- Confirm the bearing locations against the building plans.
- Identify which heel-height dimension the package uses.
- Confirm exterior eave and overhang geometry.
- Check the resulting ceiling and attic space.
- Coordinate insulation, ventilation, and service constraints.
- Retain the accepted revision before production release.
Builders FirstSource describes component design and layout services as part of its supplier offering. Ask your supplier which dimensions its design and layout service checks. Do not assume the quote transfers overall building-design responsibility. Supplier component services
Check restraint, bracing, and anchorage separately
The chord-and-web assembly is the supplied truss. Assign responsibility for restraint, bracing, anchorage, and connections to the building. Keep the installation documents for each. SBCA distinguishes lateral restraint from diagonal bracing in its terminology. Installation terminology
BCSI addresses handling, installation, temporary restraint, and permanent bracing. Read the applicable guidance and project documents before treating an installed line of trusses as ready for loading or the next stage. BCSI guide
For each restraint requirement on the drawing, ask which bracing detail completes the load path. SBCA’s delegated-design discussion addresses the top-chord, bottom-chord, and web planes and the responsibility boundaries for their stabilization. Design and bracing responsibilities
Do not use these part definitions to set bracing spacing. The component design, applicable guidance, and responsible designer determine the installation arrangement for the project.
Send the supplier a clear repair question
Include these details in your field question:
- The project and current plan revision.
- The component mark and drawing.
- The affected chord, web, panel point, plate, or bearing.
- A wide photo and close-ups showing the condition.
- Any known handling damage or proposed service change.
- The work on hold until you get an answer.
SBCA’s jobsite packages provide installation and safety information intended to reach the crew. Keep those resources with the drawings for anyone reviewing the field question. Jobsite documentation
Use the trusses and engineered-wood supplier page to identify the right technical contact before delivery. Send repair questions to that contact and the responsible designer rather than relying on a generic product photograph.
For accepted field corrections, read damaged or cut roof truss and retain the written detail with the installed work. Keep a questionable member exposed until you obtain the required answer.
Where Cercha fits
Cercha supplier profiles and portfolios help you identify component suppliers and framing trades. Messages supports the first conversation about the scope and technical contact. Use the actual design drawings and the responsible professionals for member identification, changes, and repair acceptance.