Steel roof trusses: procurement questions
Steel roof trusses are engineered components. Procurement should settle who designs them, what loads and spans they assume, how they are braced and how they are delivered and lifted.
Buying steel roof trusses is closer to commissioning an engineered product than ordering stock. The questions that matter are who designs and checks them, what loads and spans they assume, how they are braced and connected, and how they reach the site in a condition you can lift and fix. For general background, see the roof trusses procurement guide and the glossary entry for truss.
Start with the roof, not the truss
A supplier can only quote accurately from a roof plan that shows spans, pitch, overhangs, bearing walls, openings for chimneys or skylights and the roof covering. Ask the designer which loads apply: roof covering weight, snow if relevant, wind, and any equipment or solar panels planned now or later. If solar or rooftop plant is possible in the future, say so at quotation stage. Which load values apply to your site is for the engineer of record and the local authority to confirm.
Design responsibility
- Does the supplier provide truss design, and is it sealed or certified by a licensed engineer where your authority requires it?
- Does the engineer of record review the supplier's drawings before fabrication?
- What happens if the review changes a member size or connector? Who pays, and what happens to lead time?
Scope questions
| Item | Ask |
|---|---|
| Trusses | Quantity, profile types, spacing, member steel thickness and grade |
| Bracing | Temporary erection bracing and permanent bracing: who designs, who supplies? |
| Connectors and hangers | Truss-to-wall connections, uplift ties, girder connections |
| Fasteners | Type and quantity, and the coating required for the site environment |
| Installation | Supply only, supply and install, or technical supervision? |
| Sheathing and purlins | Included or separate? See roof sheathing |
Steel and coating
Ask for the steel specification and coating type, and for supporting documentation. In a coastal or humid setting, ask the engineer what protection is appropriate and how cut ends and fastener points are treated; see the coastal questions guide. If the supplier cites a certification or evaluation, verify it with the issuer using the certification checking guide.
Tolerances and the supporting structure
Trusses sit on walls that must be level and correctly spaced. Ask what bearing tolerance the supplier needs, and agree who checks the wall tops before the trusses arrive. This is a common friction point between framing and structure contractors, covered in hybrid system coordination.
Delivery, storage and lifting
- Maximum truss length and height against the transport route and site access.
- Packaging and labelling: each truss should carry a mark matching the layout drawing.
- Storage: trusses are normally kept off the ground, supported, and protected from damage; ask for the supplier's written handling instructions.
- Lifting plan: who provides the crane or lift, and who writes the lift plan?
Documents and timing
Request the layout drawing, truss profiles, connection details, installation guide and a delivery window. Ask which date freezes the roof design for production and what a change after that date costs in time; see design freeze. Place roof structure on your long-lead list if the supplier's fabrication slot is not immediate. Compare quotations on a like-for-like basis using the comparison guide.
Questions people ask
Who is responsible for truss design?
Often the truss supplier produces the design, but your project may require review by the engineer of record. Settle this in writing before ordering.
Do trusses include bracing?
Trusses normally need temporary and permanent bracing. Ask whether bracing, connectors and hangers are in the supplier scope.
What drawings should arrive with the trusses?
Truss layout, individual truss profiles, bearing and connection details and an installation guide.
Can I change the roof pitch after ordering?
Treat it as a redesign. Changes after design freeze usually mean new drawings and new lead time.
Sources and further reading
Have a project outline or drawings?
Organize your scope, then contact Digital Oro through its official channel. Availability, engineering, pricing and delivery terms need project-specific confirmation.
Explore Digital Oro →Digital Oro International advertises on The Company Chronicle. This guide was written by our editorial team from public sources and general professional practice; it does not describe a guarantee, quote or offer from Digital Oro International. Confirm current terms, prices and availability with the operator before you decide.