When building a composite deck, the foundation is just as important as the decking boards themselves. Composite Decking Joists provide a strong, stable, and long-lasting base that ensures your deck remains durable for years to come. In this guide, we will walk you through the step-by-step process of installing Composite Decking Joists, so you can create a safe and secure outdoor space.
Why Choose Composite Decking Joists?
Before we dive into installation, let’s understand why Composite Decking Joists are the preferred choice over traditional wood joists:
✅ Rot & Moisture Resistant – Unlike timber, composite joists won’t rot, warp, or absorb moisture.
✅ Long Lifespan – Made from durable materials, composite joists outlast traditional wood joists.
✅ Low Maintenance – No need for sealing, staining, or regular treatments.
✅ Eco-Friendly – Often made from recycled materials, making them a sustainable choice.
✅ Consistent & Strong – Composite joists are engineered for strength and consistency, reducing structural issues over time.
Step-by-Step Guide to Installing Composite Decking Joists
1. Prepare the Ground & Foundation
Before installing Composite Decking Joists, ensure that the ground is level and properly prepared.
✔ For Ground-Level Decks – Use a weed membrane to prevent unwanted plant growth.
✔ For Raised Decks – Ensure you have a solid substructure such as concrete footings or a timber frame.
✔ Check Drainage – Make sure water can drain away freely to prevent water pooling.
2. Lay Out & Position the Joists
Proper spacing and positioning of Composite Decking Joists is crucial for stability.
✔ Spacing Between Joists – Position joists 300-400mm apart (center to center) for optimal support.
✔ Perimeter Joists – Install outer joists first to define the deck’s shape.
✔ Cross Joists & Support Beams – Add cross-supports where needed for extra stability.
💡 Tip: Use a chalk line to ensure perfectly straight joist placement.
3. Secure the Joists to the Foundation
Once positioned, it’s time to secure the Composite Decking Joists to your base.
✔ For Concrete or Hard Surfaces: Use joist support pedestals or direct fixing with concrete screws.
✔ For Timber Subframes: Secure composite joists using strong decking screws or brackets.
✔ For Adjustable Bases: Use adjustable support feet for fine-tuning the height.
💡 Pro Tip: Always use corrosion-resistant screws or fixings for longevity.
4. Check Joist Leveling & Alignment
A well-leveled foundation is key to a flawless deck installation.
✔ Use a spirit level to check each joist and adjust where necessary.
✔ Ensure no joists are sagging or unevenly spaced.
✔ Double-check that joists are parallel for easy decking board installation.
5. Install Additional Support if Needed
For extra strength, especially for large decks or areas with high foot traffic:
✔ Double up joists under heavy load areas such as stairs or hot tubs.
✔ Use noggins (blocking pieces) between joists to reduce flex and movement.
✔ Ensure ventilation – Allow airflow to prevent trapped moisture beneath the deck.
Final Checks Before Installing Decking Boards
Before laying your composite decking boards, do a final inspection:
✅ All joists are securely fixed and level.
✅ Spacing between joists is consistent (300-400mm).
✅ Adequate drainage and airflow is ensured.
Now, your Composite Decking Joists are ready for the final step – installing your composite decking boards!
Where to Buy Composite Decking Joists?
If you’re looking for high-quality Composite Decking Joists, check out Composite Decking Company for durable and long-lasting materials.
Installing Composite Decking Joists correctly ensures your deck is stable, long-lasting, and resistant to the elements. By following this step-by-step guide, you can create a solid foundation that supports your composite decking for years to come.
Ready to start your decking project? Explore the best Composite Decking Joists and materials at Composite Decking Company today!