Installation tools & techniques

CONCEALoc® hidden fasteners

CONCEALoc® hidden fasteners give a screw free finish when using grooved boards.

Coordinated Facing Boards

Accessories available include:

  • Facia/riser drill bit
  • Facing boards: 305 x 14mm x 3.6m or 184 x 14mm x 3.6m
  • Grey or brown topped fascia fasteners
  • Grey or brown topped stainless steel decking screws
  • L-brackets to use on the first plank
  • Hidden fasteners


Hidden fastening

(For grooved planks only)
Use TimberTech CONCEALoc hidden fasteners.
175 per box, to cover 9m2
Follow the directions in the CONCEALoc box. Clips are coated brown.

Timber joist:  Use standard installation procedure for CONCEALoc.

Steel joist: A 30mm thick timber batten is required to be attached to the top of the steel joist for the CONCEALoc to fix into, as the screws must enter on a 45° angle.

Direct fastening

TimberTech recommends using TOPLoc™ stainless steel fasteners, which are available in matching colours with your order.
300 per box, to cover 8m2

Fasteners should be installed perpendicular to the deck surface and driven flush. DO NOT overdrive or splitting may occur.

Position: Fasten 19mm from the outside edge and end of each plank, using two fasteners per joist, including end joists.

Standard deck screws: These are required to be predrilled and counter sunk.
Use a minimum #8 x 60mm flat or bugle headed stainless steel screws, driven flush with deck surfaces.

Fastener mushrooming may occur when a non-composite deck screw is driven into the decking. If mushrooming occurs, lightly tap the material back into the hole. It can be greatly reduced or eliminated altogether by using a screw designed for composite products.

Nails: TimberTech does not recommend using nails, however, if nails are to be used, use stainless steel or high quality coated nails. Small headed ring shank/annular groove nails provide minimal fastener exposure.

Extreme caution must be used. Do not overdrive the nail as it could cause the planks to split, particularly at the ends.
Nails should be driven so that the head is flush with the plank surface.

Installation tools required

TimberTech planks can be installed with standard wood working tools as they are easily cut and shaped.

When working with TimberTech products be sure to wear the correct protective equipment.

When cutting planks with a circular saw it is recommended that a thin kerf 40-tooth alternate top bevel finish blade be used to achieve the cleanest cuts.


DO NOT use glue or caulk to fasten planks or to seal the joints between planks or any other surface, as this will inhibit the natural expansion and contraction of the planks and impede drainage of the deck.

Technical Guidelines

Plank size: 136 x 24mm x 4.8m Span: A maximum of 450mm centres

Intended use: TimberTech decking is NOT intended for use as structural members of the deck.

Lm/m2 coverage Cover width 136
  Gap 3mm
  Total 139
    7.19 Lm/m2


Slip resistance: ASTMF1679 Standard Test Method (average)

  Reliaboard Terrain
Dry 0.63 0.50
Wet 0.55 0.45


Deck slope: To aid water run-off, the deck should slope away from the house.

Joist Spacing Centre to centre 4KPa load

Plank Angle 90º 30º 45º
Spacing 450mm 350mm 300mm


Gapping requirements:

  • Deckmate spacing tool is recommended to give perfect gapping. (Supplied complimentary on request with orders.)
  • Gap planks a minimum of 3mm side-to-side.
  • Allow 3-5mm minimum gap where deck meets adjoining structures.
  • End-to-end gapping guidelines for various temperature ranges:
0º and below 1-24ºC 25ºC and above
4mm 3mm 2mm

Cantilevering: TimberTech decking can be cantilevered a maximum of 25mm.

Stair installation: Stair stringers are to be set at a maximum of 250mm centres.

Directional notch: TimberTech product surfaces are directional in manner. A notch has been added to one side of the planks. When installing planks, this marked edge must be laid to the same side for the entire installation for a consistent appearance.

Clearances: Ventilation is important; a cavity is required between the underside of the deck and the surface below.

  • Concrete or similar 50mm clearance
  • Dirt or similar  150mm clearance

Storage and handling:

  • Read installation instructions carefully.
  • Store on a flat surface and cover with non-translucent material.
  • Carry planks on edge for better support.
  • Never dump TimberTech materials when unloading.

Expansion and contraction: TimberTech decking boards will expand and contract with changes in temperature. Expansion and contraction are most significant where extreme temperature changes occur. Fastening the deck planks according to the gapping requirements noted in the table will accommodate for this movement. Changes in length are most significant during the installation process, and should be accounted for if working in extreme temperatures. For example, if planks are cut to length during a hot afternoon and left overnight before installing the next morning when it is cooler, they will contract in length. Another example would be storing and cutting your planks in the shade and installing them in direct sun. Chances are you will notice a certain amount of contraction. The best way to minimise this problem is to fasten your planks as soon after cutting as possible.

Colour and grain patterns: TimberTech decking boards are designed to mimic the look of real wood, and like real wood there will be a slight difference in colour and grain pattern from board to board. This is intentional and part of the manufacturing process which gives TimberTech decking the most realistic and wood-like appearance possible. This variation is purely aesthetic and does not or will not affect the performance of the product.
ReliaBoards® are designed to naturally weather over time. Most of the weathering process will take place within the first year of the deck’s life.
This is purely aesthetic and does not or will not affect the performance of the product.

Salt or chlorine contact: TimberTech deck planks are not adversely affected by salt or chlorine and therefore are ideal by the pool or ocean.


Property (*ultimate values) Results
Coeff. of Thermal Expansion - Width 6.1 x 10-5mm/mm/ºC
Coeff. of Thermal Expansion - Length 3.6 x 10-5mm/mm/ºC
*Flexural Stiffness (3% Strain) 1224000kN.mm2
*Modulus or Rupture (3% Strain) 21.8MPa
*Modulus or Elasticity (3% Strain) 3738MPa
Screw Pull Through 1377n/m
Water Absorption - % mass <1.29%