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Timber Species & Selection Guidefor High-Performance Joinery

The choice of timber species is one of the most critical decisions in designing and building durable, beautiful, weather-resistant joinery. The right timber can significantly improve longevity, reduce maintenance, resist moisture ingress, and support superior paint or coating performance. Conversely, the wrong species can lead to warping, decay, coating failure, or early replacement.

Please note that once an architect specifies materials like timber selection on a set of council approved plans, it will require a minor variation at a minimum to change this major detail.

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Timber Selection Criteria

What Matters Most

When evaluating timber for joinery (windows, doors, frames), here are the most important factors, and how we make them work in NZ’s climate:

WHY IT MATTERS
Exterior exposure to moisture, UV, fungal activity
WHAT WE PRIORITIZE
Class 1 or better, or modified timber with proven field data
WHY IT MATTERS
Prevents movement, splitting, joint failure, paint cracking
WHAT WE PRIORITIZE
Low swelling/shrinkage, consistent moisture behaviour
WHY IT MATTERS
Ensures long life of finish systems
WHAT WE PRIORITIZE
Timber that allows strong adhesion and minimal movement
WHY IT MATTERS
Environmental credentials, carbon footprint, forest stewardship
WHAT WE PRIORITIZE
Certified / modified species that reduce reliance on dangerous preservatives
WHY IT MATTERS
Budget control, value for clients
WHAT WE PRIORITIZE
Use high-end species where needed, cost-effective species where permissible

Comparative Summary &
Recommendations

Best for highest exposure & longest life: Accoya.
For top-tier durability, minimal maintenance, and superior paint performance.
Strong alternative / sustainable choice: Abodo (thermally modified).
Good durability, less chemical treatment, solid mid-to-high performance.
Classic timber appeal: Western Red Cedar.
Warm aesthetics with moderate durability. Use with care and good finishing.
Paint-grade solid timber: Alaska Yellow Cedar.
Excellent substrate for painted finishes.
Frame / structural components: Finger-jointed Radiata Pine (H3.2 treated).
Cost-effective for frames, not suited to the worst exposure zones without strong coating and detailing.

Detailing, Finishing &
Best Practices

End-grain sealing / priming:
All cut or scribed edges must be sealed immediately to prevent moisture ingress. All end grain is sealed with an epoxy sealer at Next Level Joinery. This must be continued throughout the installation process.
Slope & water shedding design:
Horizontal surfaces must be pitched (minimum slope) and drip edges included to prevent ponding and capillary action.
Adequate overhang / recessing:
Protect exposed surfaces with overhangs or recesses to reduce exposure to direct rain and sun.
Finish system specification:
Use high-quality primers and topcoats compatible with the timber, with maintenance intervals scheduled.
Regular maintenance:
Periodic inspections, touch-up coatings, checking flashing, and re-application of sealants extend lifespan dramatically.
Proper acclimatisation & cavity detailing:
Let units acclimatize before installation; ensure backflashes, substrate integration, moisture barrier continuity.