Accoya vs. Red Grandis: Which Timber is Best for Your Project?

When choosing timber for external applications such as windows, doors, or architectural features, two options stand out: Accoya and Engineered Red Grandis. At Gowercroft Joinery, we use both materials to ensure high performance, durability, and sustainability for our clients. But which is the best option for your project?

Here, we’ll compare the two timbers across key factors like durability, dimensional stability, and sustainability to help you make the right choice.

How Do Accoya and Engineered Red Grandis Compare in Durability?

Accoya:

• Durability: Accoya is classified as Class 1 (Very Durable). It can last 60+ years above ground with sensible coating cycles and good maintenance. Thanks to its advanced acetylation process, Accoya is highly resistant to rot, insects, and weathering. When combined with our microporous coatings, Accoya’s lifespan can be extended indefinitely.

Engineered Red Grandis:

• Durability: Engineered Red Grandis, classified as Class 3 (Moderately Durable), lasts 50+ years with sensible coating cycles and good maintenance. Through the engineering process, the timber gains enhanced strength and stability, making it a more reliable choice than natural Red Grandis. Our microporous coatings further extend its durability by offering superior protection from the elements.

Conclusion: Accoya leads in durability, with the potential for indefinite longevity when maintained properly. Engineered Red Grandis provides a strong, cost-effective alternative with a solid 50+ year lifespan.

Which Timber Has Better Dimensional Stability: Accoya or Engineered Red Grandis?

Accoya:

• Dimensional Stability: Accoya’s acetylation process ensures exceptional stability. It resists swelling, shrinking, and warping even in extreme weather. This makes Accoya perfect for applications where precise fitting and long-term reliability are essential.

Engineered Red Grandis:

• Dimensional Stability: The lamination process gives Engineered Red Grandis improved stability compared to natural timber. While it performs well in most conditions, it doesn’t quite match Accoya’s ability to withstand extreme moisture and temperature changes.

Conclusion: Accoya offers the best dimensional stability, making it the top choice for projects that require precision and long-lasting reliability. Engineered Red Grandis provides excellent stability for more controlled environments.

Which Timber is More Sustainable: Accoya or Engineered Red Grandis?

Accoya:

• Sustainability: Accoya is sourced from fast-growing, sustainably managed forests. While the acetylation process is energy-intensive, Accoya’s long lifespan reduces the need for replacements, lowering its environmental footprint. It is FSC-certified and boasts a carbon-negative profile over its life cycle.

Engineered Red Grandis:

• Sustainability: Red Grandis is FSC-certified and comes from fast-growing plantations, making it a highly sustainable choice. With a carbon-negative status at the raw material stage, Red Grandis absorbs more carbon than it emits during production. The lamination process maximises material use, reducing waste, and further contributing to its eco-friendly credentials.

Conclusion: Both materials are highly sustainable, but Red Grandis has the added benefit of being carbon-negative at the raw material stage. However, Accoya’s long lifespan and low replacement rate make it a top contender for sustainable building.

Which Timber Should You Choose: Accoya or Engineered Red Grandis?

• Choose Accoya if you need maximum durability, stability, and long-term performance with minimal maintenance. It’s ideal for projects where the timber will face extreme weather conditions or where precision is key.
• Choose Engineered Red Grandis if you’re looking for a cost-effective option that balances durability and sustainability. It’s a great choice for projects with tighter budgets or those that prioritise carbon-negative materials.

Still unsure which timber is best for your project? Contact us today for expert advice on choosing between Accoya and Engineered Red Grandis for your design needs.