Solar panels can generally be installed on a properly designed steel-framed roof, provided the roof structure, connections and mounting system are designed or checked for the applicable loads.
The important question is not simply whether steel roof trusses can carry the weight of solar panels. The design team must consider how the panel weight, wind forces and other actions travel through the mounting rails, brackets, battens or purlins, trusses, walls and tie-downs.
Planning steel roof trusses for solar panels before manufacture allows the framing and solar installation to be coordinated from the beginning and can help avoid unnecessary structural changes later.
The Short Answer: Yes, With the Right Design
Steel roof trusses can support a solar photovoltaic system when the trusses, connections and supporting structure are designed or verified for the proposed installation.
Capacity depends on factors including:
- Truss span
- Steel profile and thickness
- Member arrangement
- Truss spacing
- Roof pitch
- Support locations
- Wind classification
- Existing permanent and imposed loads
- Mounting system and fixing details
- The condition of an existing roof
For a new building, the proposed solar installation can be incorporated into the structural design before the trusses are manufactured.
For an existing roof, available drawings and engineering information should be reviewed, followed by an appropriate assessment of the installed framing where required.
In both situations, steel roof trusses for solar panels need project-specific design information rather than a generic allowance for panel weight.
Solar Loads Are More Than Panel Weight
The permanent load from a solar installation can include the photovoltaic modules, rails, clamps, brackets, fixings and other roof-mounted equipment.
Although an individual panel may not be particularly heavy, the loads are transferred into the roof at specific fixing locations. The location and spacing of those fixings therefore matter.
Wind actions can be equally important. Airflow over and beneath the panels can create pressure and uplift forces. These forces travel from the modules through the mounting system and into the supporting roof structure.
The solar array can also affect the wind actions experienced by parts of the roof and their connections.
Depending on the project, the design may also need to account for maintenance access, other roof services and relevant load combinations.
A single weight figure cannot confirm that a roof is suitable for a particular solar installation.
Follow the Complete Load Path
A solar mounting system needs a continuous and appropriate load path.
On a metal roof, mounting brackets may transfer loads through the roof cladding to battens or purlins. Those members then transfer the loads to the trusses, which transfer them through the supporting walls, beams and ultimately the foundations.
Every part of that path matters.
Strong trusses do not compensate for unsuitable battens, inadequate connections, incorrect bracket spacing or insufficient tie-downs.
When planning steel roof trusses for solar panels, the panel layout, mounting system, roof framing and connection details should therefore be considered together.
Information to Provide Before Truss Manufacture
Give the truss designer the latest coordinated information available, including:
- Architectural roof plans and elevations
- Proposed solar array location
- Number and dimensions of panels
- Panel orientation and layout
- Module and mounting-system details
- Weight of the complete roof-mounted system
- Roof pitch and cladding type
- Batten or purlin arrangement
- Project location
- Building height
- Applicable wind classification
- Truss spans and spacing
- Support locations
- Skylights, vents and other roof equipment
- Proposed future solar expansion, if applicable
- Solar hot water equipment, if also proposed
A note saying “allow for solar” is not enough to identify where the loads will occur.
If the final solar system has not yet been selected, the engineer can document appropriate design assumptions and identify which information must be confirmed before manufacture.
Plan the Panel Layout Early
Early solar planning can help keep useful roof areas clear and reduce clashes with hips, valleys, ridges, skylights, vents and other penetrations.
It also allows the solar installer and structural designer to compare proposed fixing locations with the roof framing layout.
For steel roof trusses for solar panels, the array should therefore be treated as part of the overall roof coordination process.
A late change to the number of panels, their position, mounting arrangement or tilt can alter the applied loads and fixing requirements.
If the solar design changes after the structural drawings have been issued, the revised information should be checked against the approved framing design before manufacture or installation.
Wind Classification and Roof Zones Matter
Wind actions vary according to factors such as terrain, shielding, topography, building height and roof geometry.
Wind effects can also be more significant around roof edges and corners. As a result, a mounting arrangement or bracket spacing used on one property should not simply be copied to another.
The solar mounting system needs to be suitable for the specific project and installed according to the relevant engineering and manufacturer’s instructions.
The structural designer then needs to consider how the resulting reactions affect the roof framing and connections.
Bracket spacing should always be based on the applicable design and product requirements rather than assumptions from another property.
Use Approved Fixing Locations and Details
Cold-formed steel roof trusses are engineered systems. Their chords, webs, connections and bracing work together to provide the required structural performance.
Do not cut, notch, bend, drill or relocate truss members for solar equipment unless the alteration has been specifically designed and approved.
Similarly, do not assume that a screw or fixing can be placed anywhere in a thin steel section simply because it appears accessible.
The approved structural and mounting details should establish how the solar loads are transferred into the supporting framing.
Fixing type, quantity and location must be suitable for the steel thickness, member configuration and connection requirements.
If the proposed fixing cannot be installed as documented, obtain an appropriate revised detail from the relevant designer or system manufacturer.
Correct fixing is a critical part of successfully installing steel roof trusses for solar panels.
Protect the Roof From Water and Corrosion
Solar attachments must maintain the roof’s weatherproofing.
Where penetrations are required, seals, flashings and fixing details should be compatible with the roof profile and mounting system.
Material compatibility is also important, particularly for properties exposed to coastal conditions in NSW.
Brackets, fasteners and isolation materials should be suitable for the roof sheeting, steel framing and environmental exposure.
Any cut edges or damaged protective coatings should be treated in accordance with the applicable product, installation and engineering requirements.
Check Existing Steel Roof Trusses Before Installation
Existing roofs require a different approach from new construction.
Where available, the assessor may review:
- Original truss drawings
- Engineering documentation
- Previous alterations
- Roof loading information
- Existing solar or other equipment
A site inspection may also be required to assess truss spacing, bracing, connections, corrosion, damage and other existing loads.
This is particularly important where original drawings are unavailable, the roof has been extended or additional equipment has already been installed.
If strengthening is required, it should be designed and documented before the solar panels are installed.
An assessment of existing steel roof trusses for solar panels should consider the complete load path, including supporting members and connections, rather than looking at the trusses in isolation.
Solar PV and Solar Hot Water Are Different Loads
Solar photovoltaic panels and solar hot water systems should not be treated as identical structural loads.
Photovoltaic panels are generally distributed across a mounting system, whereas solar hot water systems can include a water-filled tank that creates a substantially more concentrated load.
The structural documentation should clearly identify which system is proposed.
For solar hot water, provide the equipment type, filled weight, dimensions and proposed location so the structural designer can determine whether a particular truss arrangement or additional support is required.
Coordinate Cables and Other Services
Solar cabling, isolators and roof penetrations should be coordinated with the final framing layout.
Electrical and other services should not require unauthorised cutting or modification of truss members, bracing or other structural components.
Keeping the approved structural drawings and relevant installation documentation available on site can help the construction and solar teams work from the same information.
Which Rules and Standards Apply in NSW?
This article is intended as general information, not project-specific engineering or electrical advice.
For a project in NSW, the applicable requirements depend on the building, approval pathway, structural system and work being undertaken.
As of September 2026, the NCC 2022 Amendment 2 framework applies in NSW, with the NSW Government having announced adoption arrangements for NCC 2025 from 1 May 2027. Projects that span an adoption date should confirm the applicable code, approval requirements and any transitional arrangements.
Depending on the project, relevant technical documents may include standards covering structural actions, cold-formed steel structures, residential wind actions and steel framing, as well as applicable electrical and solar installation requirements.
Potential references can include:
- AS/NZS 1170 series for structural design actions
- AS/NZS 4600 for cold-formed steel structures
- NASH standards where applicable to residential and low-rise steel framing
- AS 4055 for residential wind actions where applicable
- AS/NZS 5033 for photovoltaic array installation requirements
- AS/NZS 3000 for electrical installations
The exact standards, editions and amendments that apply should be confirmed for the individual project.
The building designer, structural engineer, frame and truss supplier, certifier and appropriately qualified solar and electrical contractors each have different responsibilities in coordinating the work.
Plan Solar Before the Roof Reaches Site
Steel roof trusses can provide a precise and efficient structural system for a solar-ready home when the design is properly coordinated.
Providing accurate information about the solar array, mounting system, fixing locations, wind actions and roof loads before manufacture allows the structural team to consider the intended installation as part of the roof design.
For an existing property, an early structural assessment can identify whether the framing is suitable and whether any designed strengthening is required.
Good coordination between the framing and solar teams can reduce site modifications, protect the roof system and help keep the installation program on track.
If you are planning steel roof trusses for solar panels, provide the framing supplier and structural designer with the latest solar information before manufacture wherever possible.
About Prime Steel Frames & Trusses
Prime Steel Frames & Trusses is a 100% Australian-owned supplier and installer serving Sydney and regional NSW. The company provides custom cold-formed steel frames, roof trusses, steel joists and structural steel solutions, supported by design consultation and an experienced team.
Builders and designers can provide the latest architectural, structural and solar information before manufacture so the framing package can be coordinated with the intended roof design.
Contact Prime Steel Frames & Trusses to discuss steel roof trusses for solar panels and obtain a project-specific quote.