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Choose timber when natural feel and repairability matter, and composite when lower routine maintenance matters more. In either case, good drainage, ventilation, correct joist spacing, corrosion-resistant fixings, and local fire or pool rules determine long-term performance.
This guide is written for South Africa, Australia, New Zealand. Always check local codes, product specifications, licences, and site conditions.
Describe the site before comparing boards
The visible board is only one component. Exposure, structure, drainage, fire or pool rules and maintenance access determine whether the deck system performs.
- Measure height, spans, access, door thresholds and the relationship to walls and ground.
- Record full sun, shade, prevailing rain, frost, salt exposure and likely surface temperatures.
- Check bushfire or wildfire, pool-barrier, balustrade, planning and building-approval requirements.
- Inspect the proposed substructure, ventilation, drainage and compatible fixing options.
- Decide the acceptable cleaning, recoating and board-replacement routine over the ownership period.
Timber and composite decking at a glance
Product quality varies widely within both groups. Compare complete systems with written span, fixing, fire, slip and warranty information.
| Priority | Timber may suit | Composite may suit |
|---|---|---|
| Natural appearance and repair | Can be sanded, refinished and locally repaired; species and treatment matter | Consistent manufactured appearance but damaged boards may need replacement |
| Routine care | Usually needs scheduled cleaning and coating appropriate to exposure | Usually avoids refinishing but still needs cleaning and stain, heat and mould management |
| Heat and sun | Colour and species influence checking, movement and surface heat | Dark boards can become very hot; expansion and fixing rules are product-specific |
| Substructure and disposal | Compatible treated structure and corrosion-resistant fixings remain essential | Board warranty does not compensate for poor ventilation, spacing or incompatible framing |
Deeper guidance
Price the whole deck rather than a square metre of board
Include design, approvals, excavation, footings, posts, beams, joists, ledgers, stairs, barriers, drainage, fixings, edge details and access. Premium boards on an inadequately drained or undersized structure are a false economy. Ask suppliers for the maximum support spacing and every location requiring special clips or screws.
Inspect safety-critical details throughout the deck’s life
Movement underfoot, soft timber, corrosion, loose barriers, ponding, cracks and damp where the deck joins the building need prompt assessment. Enclosed or waterproofed balconies deserve particular care because decay can remain hidden. Do not coat over a structural warning sign or assume that an attractive board surface proves the support is sound.
Test samples under real conditions
Place full-size samples beside the house, wet them and view them in midday sun and shade. Check glare, barefoot heat, texture, cleaning and colour beside fixed finishes. Near pools or coasts, confirm slip and corrosion requirements; in fire-prone areas, obtain project-specific evidence rather than relying on a generic marketing label.
Step by step
Map the exposure
Note sun, shade, salt air, rainfall, bushfire or wildfire risk, pool splash, ground clearance, and airflow.
Compare whole-life care
Price cleaning, coatings, board replacement, fasteners, and disposal over the years you expect to own the deck.
Check the system
Confirm span tables, joist centres, end gaps, ventilation, fixing zones, and compatible substructure before buying boards.
Test a sample
View samples wet and dry, in full sun, and beside the house. Check heat, glare, texture, and slip under realistic conditions.
Expert tips
- Dark boards can become very hot in strong sun.
- Near the coast, fixing and connector corrosion resistance is critical.
- Keep the substructure accessible for inspection.
Common questions
Is composite decking maintenance-free?+
No. It usually needs less refinishing than timber, but it still needs cleaning, drainage, ventilation, and occasional stain or mould treatment.
Which decking lasts longest?+
Service life depends on product quality, exposure, installation, ventilation, and maintenance. A well-detailed system usually outlasts a premium board installed poorly.
Can decking be installed directly on soil?+
Boards should not sit directly on soil. Use an engineered, drained, ventilated support system suitable for the site.
Sources & further reading
We link to official building-code, government and public-health material where a technical or safety claim needs authoritative context. Local rules and adopted code editions can change.
- New Zealand Building PerformanceDecks and balconies — playing it safeOfficial guidance on consent, drainage, decay, corrosion, barriers and warning signs in decks and balconies.↗
- Australian Building Codes BoardNCC Housing Provisions Part 12.1National-code context for deck and balcony attachment, bushfire areas and related construction provisions.↗
- South African GovernmentNational Building Regulations and Building Standards Amendment ActSouth African building-control and approval framework.↗
Stop if the work involves structural uncertainty, hazardous materials, heights, live services, gas, serious water damage, or regulated work. Local rules differ—use an appropriately licensed professional where required.