Vulcan decking installation guide

Before you start

Handling and storage

• Keep decking boards flat and dry before installation.
• Stack on bearers at least 100 mm above the ground and under cover.
• Allow air circulation around the timber.
• Wear gloves, safety glasses, and a dust mask when cutting or handling boards.
• Do not re-machine or use the timber for purposes other than decking.

Compliance
All decks must meet New Zealand Building Code requirements. Consult a qualified builder or designer for elevated decks or complex structures.

Planning your deck

Board size and fixing

• Board dimensions: 142 x 27 mm
• Space joists at 450 mm centres maximum.
• Allow 6 mm gaps between board edges and 1–2 mm at butt ends.
• Position fixings 18 mm from the board edge and 12 mm from ends.
• Use two 60 mm x 5 mm stainless steel self-drilling, self-countersinking head screws per joist.
• Nail fixing is not recommended.

Ventilation and drainage

• Maintain at least 300 mm clearance above ground for airflow.
• Waterproof damp substrates with membrane and ensure a minimum 5° fall for drainage.
• Do not block airflow with cladding or landscaping.

Pro tip: Always install Vulcan with the reeded face up. This helps reduce surface checking and improves slip resistance.

Step-by-step laying instructions

1. Prepare the substructure
   

   Ensure all joists and framing timber are dry, level, and durable enough for exterior use. Use timber with durability Class 1 or 2, or treated to H3 standard. Confirm joist spacing and fall direction before starting.

2. Layout and pre-seal
   
   • Lay out boards to balance length and width across the deck.
   • Cut to required lengths.
   • Bevel all cut ends slightly to prevent water pooling.
   • Seal ends immediately with Abodo Protector End Seal or equivalent wax sealer.
   
   

Pro tip: Sealing all cut ends, notches, and penetrations is essential to prevent moisture absorption.
3. Fixing boards
   
   • Start fixing from one edge and work row by row across the deck.
   • Use a string line to maintain straight lines.
   • Fix boards with the ribbed face up.
   • Pre-drill only at board ends using a drill bit one-third smaller than the screw diameter.
   • Drive two screws per joist, 18 mm from each edge and 12 mm from the end.
   • Fix screws flush with the surface, not below it.

Pro tip: Stagger butt joins across different joists to improve appearance and strength.
4. Allow for expansion
   

   Vulcan timber is dry and will expand slightly once exposed to moisture. Maintain the recommended 6 mm side gap between boards and 1–2 mm end gaps at butt ends at butt joins to allow for this movement. Once installed, wash down the surface with mild detergent and clean water. Let the deck weather for a few weeks before coating to improve adhesion. You can leave Vulcan decking to naturally silver off, or coat with a penetrating decking oil or stain for colour retention.

   • For minimal maintenance, use a clear, non-pigmented oil and allow natural greying.
   • For colour preservation, use a brown pigmented stain and reapply regularly.
   • Always test coatings on a small section first.

Finishing

Once installed, wash down the surface with mild detergent and clean water. Let the deck weather for a few weeks before coating to improve adhesion.
You can leave Vulcan decking to naturally silver off, or coat with a penetrating decking oil or stain for colour retention.

• For minimal maintenance, use a clear, non-pigmented oil and allow natural greying.
• For colour preservation, use a brown pigmented stain and reapply regularly.
• Always test coatings on a small section first.

Pro tip: Coating both top and bottom surfaces before installation can slow weathering and reduce surface checking in exposed decks.

Maintenance and care

Routine cleaning
Wash your deck at least every six months using mild detergent, warm water, and a soft brush.
 Avoid harsh chemicals or high-pressure washing close to the surface.

Maintaining colour and protection

• Reapply pigmented stains or clear oil every 12–18 months.
• All timber will fade to grey if left uncoated. To retain colour, maintain coatings regularly.
• Surface checking can occur naturally; installing with the ribbed face up and maintaining coatings reduces this.

Mould and mildew

• In humid areas, mould growth can occur.
• Clean with Abodo Rejuvenator or a similar oxygenating cleaner.
• Apply a mould inhibitor such as Resene Deep Clean after washing to prevent regrowth.