• Keep decking dry and protected until it is ready to install. Store packs off the ground on dry, clean bearers and cover them to protect from sun and rain.
• Avoid sealing the cover completely allow for air flow.
• Handle boards carefully to prevent edge damage or distortion.
• Decking should always be acclimatised on site before fixing - generally for 7-10 days depending on weather and moisture conditions.

• To reduce splitting and checking at board ends, seal all freshly cut ends as soon as possible using a penetrating oil or wax-based end sealer.
• Apply before installation for best results.

• Good ventilation underneath the deck is vital for long-term performance.
• Allow a minimum 450 mm clearance between the ground and the underside of the joists to maintain airflow and minimise cupping or warping.
• In damp or coastal areas, increase clearance and use a ground vapour barrier (with slit drainage).
• Do not fully enclose the sides of the deck - keep the perimeter open to promote air circulation.

• Timber expands and contracts with moisture. Kiln-dried (KD) timber will take on moisture after installation, while air-dried timber may shrink slightly.

• A well-designed deck performs better, lasts longer, and requires less maintenance over time.
• Thoughtful planning of airflow, drainage, and sun exposure prevents moisture build-up, timber movement, and premature weathering.
• Follow these guidelines to maximise deck performance and ensure your investment stands the test of time.
  
  
  
  
  
  
  
  

• Maintain a minimum 450 mm clearance between the ground and the underside of joists.
• In damp or coastal locations, increase this clearance to promote air circulation and faster drying.
• Avoid installing decks directly onto concrete pads or impermeable surfaces unless a drainage path or spacer system is provided.

• Always design the deck with a fall of approximately 1 in 100 (10 mm per metre) to encourage water run­off away from buildings and structures.
• Run decking boards perpendicular to the direction of fall to assist drainage.
• Check that water can flow freely between boards and does not pool at joist junctions or wall interfaces.
  

• Allow for cross-flow ventilation beneath the deck by leaving openings or vents at the perimeter.
• If the deck is enclosed on one or more sides, include ventilation grilles or slotted facings to maintain airflow.
• Free air movement under and around the decking reduces cupping, warping, and decay.

• Plan for balanced exposure — areas under constant shade may stay damp, while full-sun decks may dry rapidly and need more frequent oiling.
• Consider how nearby landscaping, fencing, or rooflines affect airflow and UV exposure.

• Face fixing with screws is strongly recommended for both hardwood and softwood decking.
• Use stainless-steel screws for all coastal or exterior environments.
• Hot-dip galvanised screws may be used on treated softwood where stainless is not required.
• Screws should penetrate at least 45 mm into joists for adequate holding.
• Pre-drill and countersink all screw holes — this prevents splitting, especially near board ends.
• Position screws approximately 20 mm from edges and ends.
• Do not use self-drilling screws with small heads — They can tear or split timber.

• Coating all four sides of the decking boards before installation helps reduce moisture movement and surface checking.
• Use a quality exterior decking oil or sealer.
• Eris.re boards are clean and dry before coating.
• Clear oils will allow natural silvering over time; tinted or pigmented oils retain colour longer.
• Do not apply film-fanning coatings (such as varnish) — these can blister and peel in exterior conditions.
  

Pre-oiling and staining service

• Botica Group's Botica Timber Services Ltd offers professional oiling and staining capabilities that coat all four sides of each timber length.
• This process achieves far better coverage and protection than oiling or staining after installation and ensures the product is ready for site use straight from delivery.

Toasted Range (Thermally Modified Timber)

• Our Toasted Range timbers are naturally durable and chemical-free, but they still benefit from protective oiling.
• We recommend applying a penetrating exterior oil to all faces before installation to stabilise the timber, reduce surface checking, and preserve colour.
• Regular re-oiling (every 12-24 months depending on exposure) will help maintain performance and appearance in New Zealand's variable climate.

• Adjust spacing for regional climate conditions - use slightly wider gaps in coastal or high-humidity areas.
• Maintain a minimum 450 mm ground clearance under the deck for proper airflow.
• Free air circulation reduces cupping, warping, and surface breakdown.
• Avoid enclosing deck perimeters - open sides promote timber longevity and consistent colour.

• All softwood decking used externally must be H3.2-treated or higher to comply with the New Zealand Building Code durability requirements.
• Use H4 treatment where timber is in contact with the ground or within approximately 150 mm of soil or concrete.
• Always ensure suitable drainage and ventilation to prevent prolonged moisture exposure.

• Timber expands and contracts as it adjusts to ambient moisture.
• Kiln-dried (KD) decking will take on moisture after installation and expand slightly.
• AA-dried (AD) decking will Ass moisture and shrink slightly as it settles.
• To allow for this natural movement and ensure proper drainage, leave consistent gaps between boards.

FOR TYPICAL RECOMMENDATIONS FOR DECKING SIZES COMMONLY USED IN NEW ZEALAND, PLEASE REFER TO THE TABLE ON THE FOLLOWING PAGE.

• Keep the deck free of leaf litter and debris to prevent mould and decay.
• Clean with a stiff brush and mild detergent or a 1:16 solution of Janola and water once or twice per year.
• Re-oil the deck as needed - generally every 6-12 months, depending on exposure.
• Move pot plants and furniture occasionally to prevent moisture from being trapped beneath them.

• Use treated pine (H3.2 or higher) for all exterior applications.
• Ensure fasteners are compatible with the treatment type to prevent corrosion.
• Softwood moves more readily with moisture; sealing all faces before installation is especially important.
• For thermally modified pine (Toasted Range), always follow the above coating recommendations prior to installation.
• Customers can request pre-oiling or staining by Deck King Ltd to achieve full 4-sided protection prior to delivery.
  

• This guide has been prepared in accordance with recognised New Zealand timber industry standards, including NZS 3602:2003 (Timber and wood-based products for use in building) and NZS 3640:2003 (Chemical preservation of round and sawn timber), to assist correct installation and ongoing maintenance of timber decking.
• Information is provided in good faith for general guidance only. Site-specific requirements should be confirmed with your builder, engineer, or local authority.
• Reference to New Zealand Standards is provided for general guidance only and does not imply endorsement or certification.
• The information is provided in good faith to assist correct installation.
• As the timber supplier, we advocate coating and maintenance best practices to ensure product performance.