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This extruded 6063 T6 aluminium rail has been designed and developed by Wallbarn for construction of heavy duty paving or decking applications. These profiled rails are designed to connect seamlessly to our Mega Balance, Joist Holder & MetalPad Ex pedestals.
Initially developed as a low-height substitute for timber and composite joist/rails, it is now a standard choice for fire rated substructure systems. It is extremely strong, lightweight and simple to install.
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If you have any questions, get in touch.
| Rail height | Maximum distance between pedestals | Recommended maximum distance |
|---|---|---|
| 15mm | 600mm | 500mm |
| 20mm | 800mm | 625mm |
| 25mm | 1000mm | 625mm |
| 50mm | 600mm | 600mm |
| 75mm | 1200mm | 1200mm |
| 100mm | 2200mm | 1800mm |
If you have any questions, get in touch.
There are a range of brackets designed for use with our aluminium Box Rail. These options include:
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Box Rail is a lightweight, high-strength aluminium rail and joist designed for suspended paving and decking installations.
Manufactured in the UK from 6063 T6 extruded aluminium, the profiled rail was originally developed as a low-height alternative to conventional timber and composite joists. Its design combines a compact construction with the strength required for demanding external applications.
The rail connects to compatible adjustable pedestals and works with purpose-designed paving headpieces, decking fixings and brackets to create a stable supporting framework.
Box Rail can form part of both standard raised surface systems and non-combustible Class A substructures, depending on the other components selected.
Full product information is available in the Aluminium Box Rail Operations & Maintenance Manual.
Box Rail is suitable for a wide range of residential and commercial paving and decking installations, including:
Its low-profile construction is particularly useful where an existing timber or composite substructure needs to be replaced without significantly increasing the finished surface height.
The rail can also be incorporated into larger supporting frameworks where additional lateral strength and consistent alignment are required.
The complete installation must be designed around the structural deck, anticipated loading, fire strategy and selected surface finish.
Aluminium Box Rail provides a durable, dimensionally stable alternative to conventional timber or composite supporting structures.
Unlike timber, aluminium will not rot or warp through prolonged exposure to moisture. Its extruded construction also provides consistent dimensions, helping installers create straight, accurately aligned frameworks.
The rails are lightweight and easy to handle, making them particularly suitable for rooftop installations and projects where access is restricted.
Box Rail also offers the benefit of a published Class A1 fire classification, allowing it to form part of a suitably specified non-combustible substructure.
Its profile has been purpose-designed to connect with compatible Wallbarn pedestals and accessories, simplifying installation and helping create a coordinated supporting system.
Box Rails are available in three profile heights:
All three profiles are 60mm wide and supplied in standard lengths of 2,400mm.
The low-profile construction allows the rail to be selected according to the available build-up height and the support requirements of the project.
For larger spans or greater build-up heights, the deeper I-Plus Rail range provides 50mm, 75mm and 100mm alternatives.
Detailed dimensions, profile drawings and material properties are available in the Aluminium Box Rail technical documentation.
Yes. The aluminium Box Rail has a published Class A1 fire classification to BS EN 13501-1:2018.
This makes it suitable for incorporation into appropriately specified non-combustible paving and decking substructures.
For a complete Class A supporting system, Box Rail can be combined with compatible metal components, including MetalPad EX fire-rated pedestals, metal headpieces, brackets and fixings.
The classification of the rail should not, however, be confused with the fire classification of every other component in the completed installation. The selected paving, decking, pedestals and other materials must also be appropriate for the project fire strategy.
Further information is available within the Class A Rail Substructure System.
Box Rail has been designed to integrate with both Wallbarn's plastic pedestal systems and its non-combustible metal supports.
Compatible options include:
The rail's outer ledges connect directly with compatible MiniPad and Mega Balance headpieces, allowing the rail to click securely into place without mechanical fixings at that connection.
For MetalPad EX installations, the rail is mechanically secured using the M8 Wing Nut Kit.
This compatibility makes Box Rail suitable for a wide variety of project requirements while retaining the same core aluminium profile.
Box Rail has been specifically designed for projects where available threshold height is restricted.
When combined with the appropriate Ultra-Low Class A Rail Holder, the supporting substructure can start from approximately 17mm high.
This is particularly useful on balcony refurbishments and retrofit projects where existing doors, thresholds and surrounding levels cannot easily be altered.
The final finished floor height will also depend on the selected paving or decking thickness, headpieces and any additional protection or support components.
Using the appropriate combination of components allows installers to create an extremely low-profile metal framework without unnecessarily increasing the completed surface level.
Yes. Box Rail can be used to support suitable suspended paving, including porcelain tiles and planks, natural stone and concrete slabs.
Purpose-designed paving headpieces clip directly onto the aluminium rail and can slide along its length until positioned beneath the required edges or corners of the paving units.
This allows the support arrangement to be matched to the paving layout rather than being restricted to the exact pedestal positions beneath.
The headpieces incorporate positioning lugs that maintain consistent joints between adjacent slabs, allowing rainwater to pass through the finished surface.
The suitability of individual paving products will depend on their dimensions, strength, thickness, anticipated loading and the proposed support arrangement.
Further information is available on the Fire-Rated Paving System page.
Yes. Box Rail is suitable for compatible timber, composite and non-combustible decking systems.
Its 60mm-wide profile provides a substantial upper surface for the appropriate mechanical fixing arrangement.
For projects requiring a non-combustible finish, compatible options include:
Purpose-designed concealed decking clips can be used with suitable profiled boards to create a secure installation without visible fixings through the upper surface.
Where conventional decking is selected, the appropriate fixing method must be used for the board material and joist arrangement.
The permitted span depends on the depth of the Box Rail, the load applied and the complete supporting arrangement.
The 15mm, 20mm and 25mm profiles have been independently assessed for load and deflection performance. The deeper profiles provide greater spanning capability, which can offer additional flexibility when positioning pedestals around roof features or other obstructions.
Pedestal spacing should be selected using the appropriate published load and deflection guidance for the rail profile and installation configuration.
The strength of the paving or decking, intended pedestrian loading, support conditions and capacity of the underlying structural deck must also be considered.
For current project-specific spacing requirements, refer to the Box Rail technical documentation and confirm the proposed layout with our technical team.
Yes. Box Rail has undergone independent testing by Specialist Technical Services (UK) Ltd.
Testing has examined the performance of the different aluminium profiles under applied loads, including assessments of deflection at different support distances.
The testing methodology references BS 8579:2020 and BS 8527:2020, with a 5mm deflection criterion used for evaluating suitable support arrangements.
The 25mm Box Rail was also redesigned in late 2024 to increase its strength, and the current technical documentation distinguishes the revised profile from the earlier version.
These test results provide valuable evidence for specification, but the load achieved during an individual laboratory test should not automatically be treated as the permitted working load of every completed paving or decking installation.
Independent test information is included within the Aluminium Box Rail Operations & Maintenance Manual.
Box Rails can be connected using purpose-designed straight and right-angle brackets.
These allow individual rail lengths to be joined end to end or positioned perpendicular to one another to create a connected framework.
The brackets are secured using the appropriate mechanical fixings, helping installers establish a strong, accurately aligned substructure.
Additional cross-members, often called noggins, can also be incorporated where greater lateral stability is required.
For projects involving more complex levels or substantially larger build-up heights, a Class A Rail-to-Rail Headpiece allows compatible aluminium rails to be positioned in perpendicular layers.
This gives designers additional flexibility when constructing a raised supporting framework.
Yes. Box Rail can be incorporated into suitable raised systems above concrete, protected waterproofing membranes and insulation.
The rail itself is normally supported by compatible pedestals rather than placed directly onto the waterproofing.
Where pedestals are installed over vulnerable surfaces, the waterproofing or insulation manufacturer should confirm that the proposed loading and support arrangement are appropriate.
For suitable fire-rated pedestal installations, an optional Spreader Plate can help distribute the load over a wider area and reduce concentrated point loading.
Box Rail can also be incorporated into projects involving existing steel substructures. Where aluminium and steel are used together, an appropriate connection and separation detail should be adopted to help reduce the risk of galvanic corrosion.
The proposed installation should always be coordinated with the supporting structure and waterproofing specification.
Box Rail forms part of a suspended supporting framework, creating a cavity between the finished paving or decking and the underlying structural deck.
For paving installations, the positioning lugs on the compatible headpieces maintain open joints between adjacent slabs. These allow rainwater to drain through the finished surface.
For decking, the joints between boards perform a similar function, allowing water to pass through to the drainage level beneath.
The raised construction keeps the finished surface separate from the waterproofing and provides space for water to travel towards designated roof outlets.
The structural deck must retain its intended drainage fall, and outlets should remain accessible and clear of debris.
Where removable paving is used, individual units can also be lifted to provide access for inspection or maintenance.
Box Rail is manufactured from high-grade extruded aluminium and is designed for long-term external use.
The rails will not rot or warp and require relatively little direct maintenance once correctly installed.
The main ongoing requirement is to ensure that the drainage system beneath the paving or decking continues to function effectively.
Periodic inspections should focus on keeping drainage channels and outlets clear, removing leaves and debris, and investigating any unexpected movement or standing water.
The published technical documentation gives the aluminium rails a 15-year limited product performance warranty and an expected lifespan of up to 50 years, subject to correct specification, installation, intended use, maintenance and the applicable warranty conditions.
Full care and warranty details can be found in the Aluminium Box Rail Operations & Maintenance Manual.
