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Composite decking has some specific characteristics and requires different fixing methods to timber. We therefore strongly recommend that these guidelines are read thoroughly before commencing the design and construction of the deck.


PERMADECK™ composite decking should be stored covered, flat and off the ground. Standard 5800mm long packs of PERMADECK™ require a minimum of eight gluts (supports) under the pack for proper storage.

Safety & Tools
Standard safe practices should, of course, be employed when using any tools during installation. PERMADECK™ composite decking can be drilled, sawn, fastened or routed with normal woodworking tools.

Foundation & Sub-structure

PERMADECK™ composite decking is not for use as a component of the foundation or substructure. When constructing the substructure care must be taken to ensure that the joists are level, straight and square as PERMADECK™ decking will conform to the joists.  As a general rule the closer the joists the better the deck.  

Do not exceed the maximum joist spacing specific for each profile. Any overhang of decking boards at the ends or sides of the deck should be kept to a maximum of 50mm. Breaker boards and all board ends must be positioned above and secured to a joist.  A fall of 3-4mm per metre away from the house should be planned for water run off.  

PERMADECK™ composite decking should not be attached directly to any solid surface or watertight flooring system.  For adequate airflow and drainage 5mm between each PERMADECK™ composite decking board and a minimum of a 100mm ground clearance is recommended

Expansion, Contraction & Breaker Boards

All products with a plastic component will expand when temperatures increase and this must be allowed for when planning a deck using composite material.

 Permadeck boards will elongate by a maximum of 1mm per metre when heated from cold.  We recommend the use of Breaker boards on any deck longer than 6 metres to limit the expansion/contraction gaps to 6mm. The traditional butt joining of boards is advised against.

The preferred method of deck design incorporates the use of breaker boards that are run across the deck at 90 degrees to the ends of the long boards so that the maximum gap possible is 5mm.   Additional joists/support is required in the substructure wherever a breaker board is being used.

This section illustrates the equator fastener specially cut to fit and secure the breaker board.

Permadeck boards will elongate by a maximum of 1mm per metre when heated from cold.
We strongly recommend the use of Breaker boards on any deck longer than 6 metres to limit the expansion/contraction gaps to 6mm.

Colour & Orientation

We recommend that wherever possible you purchase all of the boards required for your project at the same time in order to avoid any possible colour variation that may occur between different manufacturing runs.

The natural fibres used in the manufacture of PERMADECK™ composite decking may mean some colour variation between boards and initially in full sun the colour will lighten a little.  This will stabilise after 8-12 weeks of full sun exposure.

The grain of PERMADECK™ composite decking will reflect light differently depending on the orientation of the boards. To ensure an even look across the deck it is advisable to lay out the deck boards before fixing to allow you to check your colour mix and grain orientation, this also ensures that each board is the same temperature prior to any cutting.

Starting and Finishing Boards

The first board laid on your deck is referred to as the starter board and will normally be installed with one "free" edge either gapped against the side of a wall or freestanding at the edge of your deck. The starter board can only be fixed with the stainless steel starter clip on the inner edge.

This section illustrates the equator fastener specially cut down to fit the starter board at the front edge of the deck or against a wall. Before tightening the screw on the deck clips on your starter board, make sure you place your next deck board over the deck clips so that both edges of the Hidden Fasteners are located. The finishing or last board should be treated in the same way as the starter board.

Fastening the boards to the joists

It is recommended that PERMADECK™ Hidden Fasteners and 316 Stainless Steel Screws are used when installing PERMADECK™ composite decking.  

Standard 60mm screws with the applicable coating or stainless steel decking screws can be used, however the screw heads will be visible and the added value of the concealed fixing option will be lost.

Nailing is not recommended, and voids warranty.
This section illustrates the equator fasteners specially cut to fit and secure breaker boards, starter boards and finishing boards by using the hidden fastener system.

Screw fixing

Pre-drilling and countersinking is recommended in order to reduce the risk of splitting when screwing directly in to the face of the PERMADECK™ composite decking.

A minimum screw length of 60mm is required.  Drivers should be adjusted to a low or medium torque setting when fixing screws in to PERMADECK™ composite decking. Screws should not be over tightened into the decking.  

Screw fixing directly through the PERMADECK™ board is not recommended on steel joists due to the different expansion and contraction characteristics of the two materials.


PERMADECK™ boards are designed to be installed with adequate gapping around the boards to aid air flow. Using Hidden Fastener deck clips to fix the boards to the joists sets a gap between the sides of each board and is the preferred fixing method.

PERMADECK™ composite decking expands when warm and contracts when cold.  It is important to be cognisant of the board temperature prior to cutting in order to determine the gap requirements when installing the decking

It is advisable to have all of the boards at the same temperature by spreading them evenly over the deck surface prior to installation.

Equator Hidden Fastener Installation

15 Equator Hidden Fasteners are required per 5800mm board if mounted on 400mm centre joists.  Equator Hidden Fasteners can be installed in just four easy steps:

  1. Place an Equator fastener in the slot of the composite deck board at each support joist.
  2. Insert a stainless steel screw through each fastener into the joist.
  3. Slide the next deck board into place so that the wings fit into the slot on the deck board side.
  4. Repeat this process until the deck is complete.

To find out more about Permadeck Composite Wood decking solutions, please contact our knowledgeable team by emailing: or phone us on 0800 952 952.