Solar L Feet & Hanger Bolts
L feet connect compatible roof attachments or bases to PV mounting rails. Hanger-bolt assemblies create a threaded fixing to an approved timber or steel supporting member below the roof covering. Select the assembly from the roof, substructure, rail interface, fastener design and sealing detail.
- Slotted L Feet
- Hanger-Bolt Sets
- Timber / Steel Substructure
- Rail Interface Matching
- System-Specific Sealing
L Foot and Hanger Bolt Perform Different Jobs
An L foot is a bracket interface between a compatible roof attachment or base and the mounting rail. Its slot or hole provides the rail connection and, in many designs, a defined range of height or position adjustment.
A hanger bolt is a structural fastener assembly. Its lower fixing section engages the approved supporting material below the roof, while the upper threaded section supports an adapter, climber or L-foot connection above the roof.
- An L foot is not automatically a complete roof attachment.
- A hanger bolt is not selected from total length alone.
- The roof covering does not replace the structural supporting member unless the chosen system is specifically engineered for thin-sheet fixing.
- Rail and roof interfaces must both match the selected hardware.
Choose the Structural Path Before the Hardware Set
These are system architectures, not interchangeable versions of the same part.
Slotted L Foot
Used above a compatible roof attachment, flashing, pedestal, clamp or fastener base. The slot provides a rail connection and a product-defined adjustment range.
L Foot with Approved Roof Attachment
A roof screw, flashed base, pedestal or other engineered attachment can support the L foot. The actual load path and sealing method depend on that attachment system and substrate.
Hanger Bolt with Adapter or L Foot
The lower fixing engages the specified timber or steel support; the upper threaded section connects to an adapter, climber or L foot according to the selected rail system.
What Must Be Confirmed Before an Attachment Is Chosen?
The same visible roof profile can have different substrates and therefore require different fasteners and load paths.
Roof Covering
Profile shape, material, thickness, roof build-up and the permitted penetration or attachment detail.
Supporting Structure
Timber rafter/purlin, steel purlin, deck or another approved substrate, including available embedment or fixing depth.
Rail Interface
Rail cross-section, slot or channel, bolt/nut geometry and the permitted height or position adjustment.
Project Design
Attachment spacing, structural loads, roof-manufacturer requirements and the approved installation procedure.
Match the Lower Thread to the Supporting Material
Professional systems use different hanger-bolt or solar-fastener versions for timber and steel substructures. The lower thread or hardened tip, minimum fixing depth, total length and clamping range must therefore be checked as one assembly.
- Confirm timber or steel support before choosing the lower fixing geometry.
- Allow for roof-profile height and roof build-up when calculating total length.
- Keep the sealing component in the position required by the selected fastener system.
- Match the upper metric thread to the adapter, nuts or L-foot hardware.
- Use the system's structural design to determine spacing and fastener demand.
Use the Sealing Detail Specified for the Attachment System
Penetrating attachments require a roof-specific water-management detail. Depending on the product, that may use an EPDM or fibre-cement seal, bonded washer, gasket, flashing, integrated sealing base or another documented method.
- Do not treat EPDM as a universal substitute for every roof attachment.
- Position washers and seals where the fastener manufacturer requires them.
- Control tightening so the sealing component is neither loose nor damaged by over-compression.
- Check roof-manufacturer requirements and existing roof condition before drilling.
- Use additional sealant only when the selected system or roof detail calls for it.
Adjustment Is Limited by the Actual L-Foot and Rail Geometry
A vertical slot can provide useful leveling or positioning adjustment, but the permitted range is defined by the bracket, bolt and rail interface. It should not be treated as unlimited height adjustment.
- Confirm rail slot/channel geometry and compatible nut or T-bolt.
- Check bracket thickness, slot dimensions and edge distances.
- Use the specified bolt diameter, thread and tightening torque.
- Keep the rail within the product's approved bearing and adjustment range.
Standard Parts and Drawing-Based Variants
Manufacturing and OEM content is kept concise here; detailed capability information belongs on the dedicated capability pages.
L-Foot Variants
Bracket dimensions, holes, slots and finish can be reviewed from a product drawing or reference sample.
Matched Assemblies
Hanger bolts, nuts, sealing components and adapters can be grouped after the exact system is confirmed.
Counted Order Sets
Approved hardware can be packed by model or project BOM with agreed labels and quantities.
Data to Confirm for the Actual L Foot or Hanger-Bolt SKU
Replace generic category claims with verified product-model data when the final SKU is known.
| Component role | L-foot rail interface, roof-attachment assembly, or hanger-bolt structural fastener set. |
|---|---|
| Roof / substrate scope | Exact roof covering plus timber, steel, deck or other approved supporting material. |
| Fastener geometry | Lower fixing type, thread diameter, upper metric thread, total length and required embedment/fixing depth. |
| L-foot geometry | Height, width, thickness, hole/slot dimensions, rail bearing surface and permitted adjustment range. |
| Rail interface | Compatible rail profile, T-bolt/channel nut or other specified connection hardware. |
| Sealing detail | Product-specific washer, gasket, EPDM/fibre-cement seal, flashing, integrated base or other documented method. |
| Installation data | Fastener spacing, tightening torque and structural capacity according to the selected system and project design. |
Send the Roof, Substructure and Rail Interface for an Accurate Quote
Provide enough information to identify both sides of the attachment: the supporting material below the roof and the rail connection above it. The correct L-foot or hanger-bolt assembly can then be reviewed.
- Roof profile, material and build-up
- Timber / steel / deck supporting structure
- Rail profile and connection drawing
- Required L-foot or hanger-bolt configuration
- Project design inputs, quantity and destination
L Foot & Hanger Bolt Questions
These questions focus on compatibility points that are not obvious from product photos alone.
Is an L foot itself the roof attachment?
Not always. An L foot often connects a compatible roof attachment, flashing, pedestal, clamp or structural fastener to the PV rail. The complete load path depends on the selected mounting system.
Can one hanger bolt be used for both timber and steel purlins?
Do not assume so. The lower fixing geometry for timber and steel can differ. Confirm the supporting material and use the fastener version specified for that substrate.
Does every hanger-bolt roof penetration use the same EPDM washer?
No. Sealing details are system-specific and can use different washers, seals, gaskets, flashing or integrated bases. Follow the selected fastener and roof-system documentation.
What information should I send for a quote?
Send the roof profile/build-up, supporting material, rail drawing, required attachment path, relevant project design information, quantity and destination.