Roof Racking Checklist & Building Inspection Form - Combined Document
DesignDevise has developed a combined document called the Roof Racking Checklist & Building Inspection Form which can be accessed from the Solar Resources menu on our website.
Submitting Your Inspection Data
Download Checklist
Get the latest inspection from www.designdevise.com.au/checklist.
Complete Documentation
- For racking-only jobs, complete Pages 1 and 2 only.
- For racking plus full building assessments, complete all pages of the form.
Submit Documents
You can submit your completed inspection to DesignDevise in two ways:
- Option 1: Fill out the online form on our website and click ‘SUBMIT YOUR FORM’ at the bottom of the page.
- Option 2: Download the blank editable PDF, complete it manually, and email it to solar@designdevise.com.au.
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Snapshot of the Document
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0. Inspector Details and Statement
- As the inspector, you are certifying that the document accurately reflects the real condition of the roof and structure at the time of inspection.
- Your assessment serves as an official record that may be used for engineering calculations, safety compliance, and installation planning.
- By completing this form, you acknowledge your professional responsibility to provide thorough and truthful documentation of all structural elements examined.
- If you observe anything unusual or need to document additional features — such as parapets, mechanical equipment, or other relevant items — please use the space provided for notes or sketches.
⚠️ Accurately capturing the structural information and understanding the framing system is critical, as we will be relying on this to assess the load path — especially when structural drawings are not available, which is exactly why these inspections are being carried out.
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1. Project Details
When completing this section of the form, you must:
- Record the roof label or identifier (especially important when inspecting multiple roofs or buildings at the same site)
- Document the complete street address of the site, not just lot numbers
- By pinpointing the site's location, we can analyze wind pressures and terrain categories effectively with CheckWind Software.
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2. Building & Roof Details
Building Length & Width
Accurate building dimensions are critical for structural load calculations and panel layout design.
- Measure building length and width in metres (to two decimal places)
- Document any building shape irregularities
Take measurements from the outer edges of the building structure to provide engineers with the complete footprint for calculations.
These dimensions serve as the foundation for your structural assessment and will be referenced throughout the inspection.
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2. Building & Roof Details
Purlin Spacing
Measure and record distances between purlins in millimeters (typically 600-1800mm). For roof racking only design with rails perpendicular to purlins, purlin spacing is equal to on-purlin solution fasteners spacing.
Roof Racking Design Only
- Enter the purlin spacing in this field.
- If the spacing varies, note the maximum or "variable" spacing. Add any additional details on separate pages as needed.
Racking + Building
- Record the purlin spacings on Page 5 and beyond.
- If the spacing varies, note the maximum or "variable" spacing. Add any additional details on separate pages as needed.
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2. Building & Roof Details
Roof Material
Document the roof material type, as it affects mounting system compatibility and load calculations. This impacts the roof substructure - whether fasteners are going into steel purlins, timber rafters/battens, or concrete.
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2. Building & Roof Details
Hanging Objects or Additional Dead Load on Roof
Please use the space provided to document any hanging objects or additional dead loads on the roof. This includes items that may affect structural safety or solar panel performance, such as:
– Air conditioning units
– Pipework
– Lighting fixtures
– Cable trays
– Hanging solar inverters
– Any other mounted equipment or suspended services
Noting these elements helps us assess potential impacts on load paths and overall roof capacity.
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3. Roof Sheet Details - Optional
Client Responsibility for Fastener Selection and Roof Sheeting Information
It is the client's responsibility to select appropriate fasteners for their roof type. While DD does not assess or specify fastener suitability, providing roof sheeting details (e.g. supplier, profile, and type) offers helpful context for our design team—especially for off-purlin, non-penetrative solutions. This background assists in referencing manufacturer data on wind capacity and understanding roof-panel gaps that influence wind pressure distribution.
Please note, this is not a structural assessment of the sheeting, as no design method exists for such checks.
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3. Roof Sheet Details - Optional
Client Responsibility for Fastener Selection and Roof Sheeting Information
It is the client's responsibility to select appropriate fasteners for their roof type. While DD does not assess or specify fastener suitability, providing roof sheeting details (e.g. supplier, profile, and type) offers helpful context for our design team—especially for off-purlin, non-penetrative solutions. This background assists in referencing manufacturer data on wind capacity and understanding roof-panel gaps that influence wind pressure distribution.
Please note, this is not a structural assessment of the sheeting, as no design method exists for such checks.
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3. Roof Sheet Details - Optional
Client Responsibility for Fastener Selection and Roof Sheeting Information
It is the client's responsibility to select appropriate fasteners for their roof type. While DD does not assess or specify fastener suitability, providing roof sheeting details (e.g. supplier, profile, and type) offers helpful context for our design team—especially for off-purlin, non-penetrative solutions. This background assists in referencing manufacturer data on wind capacity and understanding roof-panel gaps that influence wind pressure distribution.
Please note, this is not a structural assessment of the sheeting, as no design method exists for such checks.
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3. Roof Sheet Details - Optional
Client Responsibility for Fastener Selection and Roof Sheeting Information
It is the client's responsibility to select appropriate fasteners for their roof type. While DD does not assess or specify fastener suitability, providing roof sheeting details (e.g. supplier, profile, and type) offers helpful context for our design team—especially for off-purlin, non-penetrative solutions. This background assists in referencing manufacturer data on wind capacity and understanding roof-panel gaps that influence wind pressure distribution.
Please note, this is not a structural assessment of the sheeting, as no design method exists for such checks.
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3. Roof Sheet Details - Optional
Client Responsibility for Fastener Selection and Roof Sheeting Information
It is the client's responsibility to select appropriate fasteners for their roof type. While DD does not assess or specify fastener suitability, providing roof sheeting details (e.g. supplier, profile, and type) offers helpful context for our design team—especially for off-purlin, non-penetrative solutions. This background assists in referencing manufacturer data on wind capacity and understanding roof-panel gaps that influence wind pressure distribution.
Please note, this is not a structural assessment of the sheeting, as no design method exists for such checks.
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3. Roof Sheet Details - Optional
Client Responsibility for Fastener Selection and Roof Sheeting Information
It is the client's responsibility to select appropriate fasteners for their roof type. While DD does not assess or specify fastener suitability, providing roof sheeting details (e.g. supplier, profile, and type) offers helpful context for our design team—especially for off-purlin, non-penetrative solutions. This background assists in referencing manufacturer data on wind capacity and understanding roof-panel gaps that influence wind pressure distribution.
Please note, this is not a structural assessment of the sheeting, as no design method exists for such checks.
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3. Roof Sheet Details - Optional
- Select ‘Other’ to record roof type if not found in the list above.
Client Responsibility for Fastener Selection and Roof Sheeting Information
It is the client's responsibility to select appropriate fasteners for their roof type. While DD does not assess or specify fastener suitability, providing roof sheeting details (e.g. supplier, profile, and type) offers helpful context for our design team—especially for off-purlin, non-penetrative solutions. This background assists in referencing manufacturer data on wind capacity and understanding roof-panel gaps that influence wind pressure distribution.
Please note, this is not a structural assessment of the sheeting, as no design method exists for such checks.
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3. Roof Sheet Details - Optional
- Clip Photos: Attach pictures of clips for roof sheeting
Client Responsibility for Fastener Selection and Roof Sheeting Information
It is the client's responsibility to select appropriate fasteners for their roof type. While DD does not assess or specify fastener suitability, providing roof sheeting details (e.g. supplier, profile, and type) offers helpful context for our design team—especially for off-purlin, non-penetrative solutions. This background assists in referencing manufacturer data on wind capacity and understanding roof-panel gaps that influence wind pressure distribution.
Please note, this is not a structural assessment of the sheeting, as no design method exists for such checks.
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3. Roof Sheet Details - Optional
- Record the number of pans per sheet, cover width and rib height for roof not found in the list.
Client Responsibility for Fastener Selection and Roof Sheeting Information
It is the client's responsibility to select appropriate fasteners for their roof type. While DD does not assess or specify fastener suitability, providing roof sheeting details (e.g. supplier, profile, and type) offers helpful context for our design team—especially for off-purlin, non-penetrative solutions. This background assists in referencing manufacturer data on wind capacity and understanding roof-panel gaps that influence wind pressure distribution.
Please note, this is not a structural assessment of the sheeting, as no design method exists for such checks.
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4. Solar Array Details
Array Type
- Select solar panel mounting type and tilt angle if tilt installation.
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5. Fastener Details
KlipLok
- Select fasteners that are appropriate and compatible with the specific roof type used in the project.
- A list of Schletter fasteners is provided. If you are using fasteners from another supplier, please specify their details in the 'Other' section.
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5. Fastener Details
SingleFix Pro
- Select fasteners that are appropriate and compatible with the specific roof type used in the project.
- A list of Schletter fasteners is provided. If you are using fasteners from another supplier, please specify their details in the 'Other' section.
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5. Fastener Details
TrimFix & KingFix
- Select fasteners that are appropriate and compatible with the specific roof type used in the project.
- A list of Schletter fasteners is provided. If you are using fasteners from another supplier, please specify their details in the 'Other' section.
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5. Fastener Details
FixW-1876 Corruagated EMU
- Select fasteners that are appropriate and compatible with the specific roof type used in the project.
- A list of Schletter fasteners is provided. If you are using fasteners from another supplier, please specify their details in the 'Other' section.
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5. Fastener Details - Longline Seam Clamps
Longline Seam Clamps
- Select fasteners that are appropriate and compatible with the specific roof type used in the project.
- A list of Schletter fasteners is provided. If you are using fasteners from another supplier, please specify their details in the 'Other' section.
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5. Fastener Details
Rapid Pro
- Select fasteners that are appropriate and compatible with the specific roof type used in the project.
- A list of Schletter fasteners is provided. If you are using fasteners from another supplier, please specify their details in the 'Other' section.
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5. Fastener Details
Klicktop
- Select fasteners that are appropriate and compatible with the specific roof type used in the project.
- A list of Schletter fasteners is provided. If you are using fasteners from another supplier, please specify their details in the 'Other' section.
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5. Fastener Details
Others
- Select fasteners that are appropriate and compatible with the specific roof type used in the project.
- A list of Schletter fasteners is provided. If you are using fasteners from another supplier, please specify their details in the 'Other' section.
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Understanding Most Commonly Used Building Framing
Before proceeding to the structural information sections of the inspection document, it's essential to understand the most commonly used building structures and framing layouts. This section provides a high-level overview of two primary construction types:
- Steel portal frame buildings - widely used in commercial and industrial applications (focus of this training)
- Conventional timber framed structures - common in residential and smaller commercial buildings
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Portal Frames
Main Components
The image below show a steel portal frame structure with several key features to note. Observe the haunches - these are reinforced sections created by welding additional material at the eaves or apex to withstand higher bending moments. Understanding these enlarged section dimensions is essential for accurately calculating load capacities.
Pay particular attention to the perpendicular members connected to purlins, known as bridging. Documenting the number and configuration of these bridging elements is crucial, as they significantly impact the overall capacity of the purlin system.
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Portal Frames
Why Purlin Bridging is Important
Purlins are cold-formed steel members designed in accordance with AS/NZS 4600, and are fundamentally different from hot-rolled structural steel members, which are designed to AS 4100. We do not custom-design purlins ourselves, as doing so typically leads to conservative results. Instead, we rely on manufacturer-developed capacity tables—such as those from Lysaght—which are based on advanced testing and analysis methods beyond standard design assumptions.
The number of bridging elements is a key factor in determining purlin capacity. As seen in the Lysaght capacity table both downward (inward) and uplift (outward) load capacities improve with additional bridging. These bridging members help restrain lateral movement and prevent premature failure due to lateral-torsional buckling under vertical loading.
For instance, at a 5.4 m span, a Z10010 purlin without bridging has an outward (uplift) capacity of just 0.43 kN/m, whereas adding a single bridging element increases this to 0.71 kN/m. In comparison, for a longer 6.6 m span, the same purlin has no uplift capacity listed with either 0 or 1 bridging, indicating that additional bridging is essential to achieve any usable capacity under outward loading.
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Portal Frames
Why Fly-Bracing is Important
Fly bracing is typically installed at every second or third purlin, as illustrated in the detail below. It usually consists of angle sections fixed from the bottom flange of the steel rafter to the adjacent purlins.
When a steel rafter bends under uplift loading, the bottom flange goes into compression. Without proper restraint, this flange can buckle sideways—leading to lateral-torsional buckling (LTB) and potential premature failure. Fly bracing acts to restrain this bottom flange, reducing the risk of LTB under uplift conditions.
In contrast, during downward loading, compression occurs in the top flange, which is generally well-restrained by the closely spaced purlins at every bay. However, for solar panel installations, uplift loads can be critical—sometimes even exceeding the original roof design loads. This is particularly problematic since the bottom flange (in compression under uplift) is only braced intermittently (e.g. every second or third purlin), unlike the top flange.
As shown in the table below, increased unbraced lengths significantly reduce the bending capacity of steel members. This highlights the importance of identifying and confirming the presence of fly bracing during inspections.
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Portal Frames
Main Components
Single-span symmetrical portal frame
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Portal Frames
Types of Portal Frames
While we cannot comprehensively cover every type of building, portal frame, and framing layout in this guide, it is the responsibility of the inspector to identify the specific structural system and document it appropriately. When encountering variations not explicitly covered in our inspection checklist, please communicate these details to engineers through email, phone calls, sketches, photographs, or other suitable methods. We rely on inspectors' expertise to recognize different structural configurations and effectively communicate these observations to our engineering team.
Different Types of Portal Frames
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6. Roof Framing Layout
Roof Locations Inspected
Now that we've covered the background information, let's examine the Roof Framing Layout section of the inspection document. Your first task is to mark and number all inspection locations on the framing layout plan. In the example diagram below, three distinct locations are identified. The inspection will utilize either Type 1 or Type 2 framing layout plans, which we'll discuss in subsequent slides.
As an inspector, it's your responsibility to determine an appropriate number of inspection locations that accurately represent the entire roof structure. For highly uniform roofs with consistent framing throughout, a single inspection location may suffice. However, please note that our structural analysis will be based exclusively on the data you provide. If only one location is documented, we will assume this configuration applies uniformly across the entire roof system.
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6. Roof Framing Layout
Type 1 Layout - Uniform, Regular, No Transfer Beams
Example Plan
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6. Roof Framing Layout
Type 2 Layout - Complex, Presence of Transfer Beams etc. - You Need to Draw the Plan View
Example Plan
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7. Section Properties
Top Right Number Relates to Inspected Location Number
- From page 5 of the inspection document, you’ll see circled numbers (1, 2, 3, etc.).
- These numbers correspond to different roof inspection locations, as explained earlier.
- Each location includes multiple pages: one for purlin details, another for rafter and column information, and another for truss details.
- The document includes space for three locations by default. If you're only inspecting one area, you may ignore or delete the extra pages.
- If additional locations need to be assessed, you can manually duplicate the relevant pages to document as many inspection points as necessary to fully capture the roof's structural conditions.
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7. Section Properties
Purlin Span & Spacing
- Record purlin span and spacing.
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7. Section Properties
Purlin Types
- Select purlin type and record section properties such as depth, thickness, bridging, etc.
- If purlin is non-standard, draw a labelled sketch in the space provided.
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7. Section Properties
Purlin Continuity
- Select if purlins are single spans, continuous or lapped and for how many spans.
- Continuity/Lap could be one of the following:
- Lapped spans are usually of following types:
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7. Section Properties
Top-hats Connections
- If top-hats, record no. of connection screws to rafters.
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7. Roof Framing Layout
Timber Grade & Type
- Record timber grade and type.
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7. Section Properties
Rafter & Column Information
- Record rafter and column information.
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7. Section Properties
Rafter & Column Material/Shape
- Record rafter and column information.
- Provide a labelled sketch if other or custom shape.
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7. Section Properties
Truss Information
- Record truss information.
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Roof Racking Checklist & Building Inspection Training for Solar Panels Installation