You are pricing a roof and need to order the framing. Choosing roof trusses or rafters affects the design, attic use, and site work. Get coordinated plans, then compare bids for the complete installed roof. A materials quote alone leaves too much undecided.
A metal plate connected wood truss arrives as an engineered assembly of chords, webs, and connector plates. A conventional rafter roof uses individual framing members assembled on site. SBCA defines the manufactured truss, while AWC publishes joist and rafter span tables for specified lumber and loading conditions.
Start with the space you need beneath the roof
Ask the owner and designer to identify each area as living space, storage, mechanical space, or inaccessible attic. Put those uses on the drawings before either system is priced. An attic that looks empty may not provide the usable space you need.
Truss geometry changes with the intended roof and ceiling. SBCA shows attic, scissors, and other truss configurations. An attic truss is designed for that use, not made by removing webs from a standard truss. Ask the supplier to show the usable section, access opening, and design loading together.
For a rafter option, ask the building designer to show the ceiling, ties or structural ridge arrangement, and supports. AWC’s span-table guidance explains that span selection depends on loads, spacing, lumber properties, and deflection. Roof pitch alone does not tell you which members to use.
Make the mechanical contractor part of this conversation. Mark equipment, service access, and proposed duct routes on the same section. Request a coordinated answer before accepting either roof package. If future conversion is a priority, ask for its design implications now.
Compare what each proposal includes
Use this table as a bid-review worksheet. Use the questions to find missing work in each bid. Neither system wins on every job.
Scroll to read all columns.
| Decision | Truss proposal | Rafter proposal |
|---|---|---|
| Design basis | Which plan revision and truss criteria does the package use? | Which drawings or applicable span tables define the framing? |
| Attic use | Which spaces and loads are designed into the trusses? | Which floor, roof, and ceiling members support the intended use? |
| Site work | Who unloads, lifts, installs, restrains, and braces? | Who supplies, cuts, assembles, and connects the framing? |
| Supporting structure | Who checks truss reactions and bearing locations? | Who checks ridge, beam, wall, and post support? |
| Openings | Which roof windows, chases, and access openings are included? | Which headers and connection details are included? |
| Changes | Who revises the package before fabrication? | Who revises the roof details before field work? |
Request a written inclusion list for connectors, bracing material, delivery, lifting equipment, and return visits. Ask bidders to identify exclusions beside the price. Keep engineering review and installation responsibility visible in both proposals.
Schedule design review before framing
With trusses, several decisions move ahead of installation. The package needs agreed geometry and design criteria before fabrication release. SBCA describes the delegated design process: the building designer owns the building structural system, while the truss designer handles individual trusses.
Plan the sequence as review, resolve, release, fabricate, deliver, and install. Name the person who signs off at each step. Ask when the order must be released to meet the quoted delivery date. Ask what happens if the roof plan changes after that point.
Rafter framing places cutting and assembly work on site. Ask the framing contractor to price that work from the complete design. Establish material delivery dates, crew dates, and the questions that must be answered before cutting starts. Compare the bids without assuming either system saves a set amount of time.
SBCA identifies quicker enclosure as a potential roof-truss benefit. It does not give your project a guaranteed installation duration. Access, weather, roof complexity, crew resources, and unresolved design questions still need project-specific planning.
Put design review on the schedule for either system. Ask when the designer can answer requests for information. A crew arrival date does not close an open structural question.
Keep the design responsibilities separate
Before ordering, name the person who coordinates the whole roof with the house. Then identify the component supplier, framing contractor, and people reviewing changes. Put their contacts on the roof package cover sheet.
A supplier may offer estimating and layout services. Builders FirstSource, for example, describes truss and engineered-wood design support. Confirm the exact service in your quotation. Check what the supplier has agreed to do on your job.
Use the roof truss design guide to plan which documents the crew needs. Ask who checks bearing conditions, connection responsibilities, concentrated loads, and coordination with other drawings. Record the answers before the manufacturing release.
Do the same for the rafter proposal. Ask which details are complete and which still require design. Identify any plan changes needed if the selected system differs from the permit documents.
Price the installed roof, including handling
Send the same roof geometry, ceiling layout, attic-use requirements, and specification to both bidders. Ask for a complete scope with assumptions. Then compare these items separately:
- Design and review services included in the contract.
- Framing materials, sheathing, connectors, and specified accessories.
- Delivery, unloading, lifting, and storage arrangements.
- Installation labor and the work required before sheathing.
- The process and price basis for changes or missing items.
- Responsibility for inspection corrections and closeout records.
Use this list to compare bids, not to set prices. Avoid applying a nationwide cost-per-foot figure to a roof with unresolved scope. Ask each bidder which drawing change would require a new price.
For the truss option, review delivery and storage before accepting the drop date. SBCA’s jobsite packages provide installation and safety information. Give those documents to the crew with the roof package.
Protect the selected design during construction
Once you select a system, issue one coordinated roof package. Remove obsolete drawings from the crew’s working set. Mark changes clearly and request acknowledgment from affected trades.
For trusses, the installation plan must address temporary restraint and permanent bracing. SBCA’s BCSI guidance covers those subjects. Have the responsible parties identify the applicable details and the person checking installation. An article or supplier brochure cannot replace those job documents.
Do not change roof truss spacing to make an opening work. Ask the designer and manufacturer for a reviewed solution. If a member is damaged or cut, use the truss repair process before work conceals the condition.
Record the selected system, current drawing revision, work included in the price, unanswered questions, and person authorized to release the order. Give that record to the superintendent and framing lead. It is the handoff they need when a truck or crew arrives.
Before signing, ask both bidders to review one marked roof section with you. Point out the ceiling line, intended attic use, equipment space, and access route. Record any difference between the drawing and the quoted scope.
Send that record to the building designer. Resolve the differences before releasing either bid for fabrication or installation.
Where Cercha fits
Cercha’s trade and location search can help you identify framing contacts. Supplier profiles list brands carried, and Messages lets you start the scope conversation. Review portfolios and endorsements before requesting the project-specific proposal directly.