Aluminium Decking Installation
How to install Hyperion® non-combustible aluminium deckingDownload Guide
Aluminium Decking on Flat Roof
With solid flat foundations and flat roof areas a simple system using MESA adjustable steel support pedestals can be used. These pedestal support centres can be placed straight onto the ground with a protective rubber membrane and their heights adjusted by rotating the pedestal top.
The height dimension of the aluminium bearer will determine how often it must be supported. Ensure that the distances between support centres beneath your bearers are no greater than below.
|Aluminium Bearer Profile||Maximum Support Span|
|20 x 50 mm||400 mm|
|40 x 50 mm||600 mm|
|80 x 50 mm||1200 mm|
- This span table is for 2.5 kN/m2 with aluminium joists placed at no more than 600 mm centres.
- There should be a maximum of 600 mm between bearers in order to sufficiently support aluminium deck boards.
Preparing the Area
- Ensure the roofing membrane is 100% water-tight and free from debris.
- Check that the installation area has a drainage slope that complies with building regulations.
- It is recommended to install a gutter or scupper to allow the draining of excess water.
Laying the Pedestals
- Starting from the edge of the decking area, lay out your pedestals. The height of the steel pedestals can be adjusted by rotating the pedestal head and then locked into position using the locking nut. Refer to the Substructure Spacing section above for information on pedestal support spans.
- Beneath each steel pedestal, lay a rubber membrane (or other sacrificial membrane) to protect the roof.
- Use a spirit level to check the level of the pedestals.
- To make up for gradients in the decking area, steel pedestalscan be fixed to the bearers at an angle.
There needs to be a slope or fall of around 1:100 (i.e. 10mm of fall for every metre width or length of decking)
Laying the Bearers
- Place your aluminium bearers on top of your steel cradles. Aluminium bearers can be laid end to end, supported by a pedestal. Make sure to leave a 10 mm expansion gap between the ends of the bearers.
- A full bearer width must be used under deck board ends, therefore you should make sure to double up on bearers in your substructure at butt joints. About a 6 mm spacing between bearers at butt joints is recommended.
- Using Tek screws, the bearers can be fixed to the steel pedestals. If using 20 x 50 mm bearers, ensure you are using small Tek screws supplied by EnviroBuild.
Installing Aluminium Decking Boards
With your subframe levelled and stable, you can now start installing your deck boards.
- The first board must be fixed using starter fasteners.
- Align starter fasteners on each bearer end where you want the deck board to start. Starter fasteners should be installed on every joist.
- Securely screw each fastener into the bearer.
- Slide the first decking board into the starter fasteners. The board will comfortably fit between the top of the screws and the underside of the fasteners.
- To fix the next board 6 mm Hyperion hidden fasteners are recommended (3 mm fasteners may also be used). These should be placed into the groove of the fixed board.
- Install one hidden fastener on each bearer.
- Ensure that the screw holes in the fasteners are lined up with the bearers in your substructure.
- The countersunk part of the fasteners should be face up.
- Always use hidden fasteners at board ends.
- With butt joints, never share a fastener across two board ends. There must be one fastener per board end.
- Lightly screw the fasteners into place. Do not fully tighten yet.
- Place the next board into position against the hidden fasteners. Raise the outer edge of the board and slide into the fasteners, ensuring that the deck board edge is fully in contact with the spacer tabs on the fasteners.
- Fully tighten the hidden fasteners down to the bearers using a drill between the decking boards.
- Repeat steps 2–5 until you have reached the last two boards.
- The last board may need trimming to fit.
Installing the Last Board
Method Using 6 mm Hidden Fasteners
- Calculate the width of the last two boards, taking into account the 6 mm spacing gap that will be between them.
- Mark on the last bearer where the outer edge of the last board is going to lie.
- Using these marks, install Hyperion hidden starter fasteners onto the bearer and slide the last decking board into place.
- Insert the penultimate deck board.
- With the last two boards in place, slide the required number of 6 mm hidden fasteners down the groove by angling the boards upward. Use partially inserted screws as ‘handles’ in order to slide the clips more easily.
- Secure the fasteners to the bearers between these final two boards.
Method Using 3 mm Hidden Fasteners
- Install your deck boards up to the final board using 3 mm Hyperion hidden fasteners.
- To fix the last decking board in place it must be screwed directly to the aluminium bearers.
- Pre-drill pilot holes in the deck board 2 mm wider than the width of the screw shank.
Trimmed Final Deck Board
You may find that your final deck board must be trimmed to fit. Trimming aluminium decking boards can be done using a multipurpose cutting tool or an aluminium suitable saw blade.
Any deck board that has been cut needs to be supported along its trimmed edge. A decking edge piece should be used to achieve this.
- Before fixing into place, measure the length from the penultimate deck board up to where the deck edge piece will sit. Take into account the spacing gap from the hidden fasteners between the final two boards.
- Trim the final decking board to size so that when it is installed, it will sit comfortably into the groove of the deck edge piece.
- Remove the final trimmed board and then using a drill and Tek screws, fix the deck edge piece to your bearer ends. Use the dip in the deck edge piece as a guide for the screws and use one screw for each bearer the deck edge piece sits on.
- Slide the final trimmed decking board into place before doing the same with the penultimate decking board.
- With the last two boards in place, slide the required number of hidden fasteners into the groove between them. It may help to angle the boards upward.
- Secure the fasteners to the bearers between these final two boards.
Edge Pieces as Trims
Deck edge pieces can also be fixed to the ends of your decking to be used as a trim to give a smart, flush finish to the edge of your installed decking. Aluminium deck boards may overhang the edge of a joist by a maximum of 20 mm. Any deck board with an overhang greater than 20 mm must be supported.
- Use pan head screws to fix the deck edge piece.
- Place the deck edge piece on the end of your installed decking with the ‘base’ on top.
- Use two screws per deck board end.
Aluminium Decking on Steel Beams
Aluminium decking boards can be installed directly onto steel beams without the need for steel pedestals or aluminium bearers. The same steps as above can be followed for installing aluminium decking to steel beams, with the exceptions:
- The maximum tolerance for the steel beams is ±2 mm. This is how high or low a steel beam can be from the adjacent beam.
- Each deck board end should be supported by at least 35 mm on the steel beam.
- At least a 70 mm width is required on the steel beam to support two board ends at butt joints.