Why Ribbed Domes Are Better Than GeoDesic Domes For Hempcrete

Summary

In this video, the speaker compares rib domes to geodesic domes, explaining that while geodesic domes are typically stronger for larger structures, rib domes offer similar strength in smaller sizes and are more adaptable for custom builds. The speaker also discusses the challenges of incorporating hempcrete into geodesic domes, highlighting the difficulty of accommodating the material due to the angles and complex patterns. Rib domes, however, provide a practical solution, easily accommodating hempcrete to achieve the desired insulation and efficiency, making them an ideal choice for the speaker's project in Florida.

Takeaways

• 😀 Geodesic domes become stronger as they scale in size, making them ideal for larger structures.
• 😀 Rib domes are just as strong as geodesic domes at smaller sizes, with the ability to handle snow and wind resistance.
• 😀 Larger rib domes require custom engineering to increase strut size and strength for greater load-bearing capacity.
• 😀 Rib domes can be expanded by connecting multiple smaller domes or adding extensions, offering flexibility in design.
• 😀 Rib domes are more compatible with certain materials, like hempcrete, compared to geodesic domes.
• 😀 Hempcrete can be used in rib domes, as the structure allows for easy adaptation to the material's needs.
• 😀 Geodesic domes are more complicated and expensive to adapt for hempcrete use, often requiring two domes to work effectively.
• 😀 Rib domes can accommodate up to 14 inches of insulation, achieving an R39 insulation value, which is ideal for Florida's climate.
• 😀 The high insulation value (R39) of rib domes helps with temperature moderation, sound insulation, and energy efficiency.
• 😀 Rib domes are the preferred choice due to their cost-effectiveness, ease of adaptation for materials like hempcrete, and their insulating properties.

Q & A

Why is a ribbed dome chosen over a geodesic dome for certain applications?

A ribbed dome is often chosen over a geodesic dome when specific design requirements, such as the ability to accommodate materials like hempcrete, are essential. Geodesic domes, with their many angles and complex structures, are not as easily adaptable for materials like hempcrete, while ribbed domes can be more readily cut to accept such materials.

What is the advantage of a geodesic dome as it gets larger?

As a geodesic dome increases in size, it actually becomes stronger. This is due to the structural nature of geodesic designs, where the strength of the dome increases as the structure scales up.

Are ribbed domes as strong as geodesic domes at smaller sizes?

Yes, at smaller sizes, ribbed domes are just as strong as geodesic domes. They can handle snow loads and wind resistance similarly, making them suitable for smaller dome structures.

How does the strength of a ribbed dome change for larger structures?

For larger ribbed domes, the strength can become a concern, and engineering adjustments might be needed. To make a ribbed dome larger and structurally sound, strut sizes may need to be increased or additional custom builds may be required.

How can a ribbed dome be expanded if a larger size is required?

A ribbed dome can be expanded by adding smaller domes or by connecting multiple domes together, similar to how rooms are added to a regular house. This allows for customization in size while maintaining the structural integrity of the dome.

What is the challenge of using hempcrete in a geodesic dome?

The challenge with using hempcrete in a geodesic dome is that the many angles and complex shapes in the dome’s structure make it difficult to integrate hempcrete effectively. The material doesn't fit well with the star patterns and trapezoidal sections of a geodesic dome.

What solution did the speaker find for integrating hempcrete into a dome structure?

The speaker found that ribbed domes are much more suitable for integrating hempcrete. The trusses in a ribbed dome can be easily cut to accommodate the material, allowing for an effective and cost-efficient hempcrete installation.

Why did the speaker reject the geodesic dome solution for hempcrete?

The speaker rejected the geodesic dome solution because it would have been prohibitively expensive. Geodesic dome providers suggested building two geodesic domes to encase the hempcrete, but the cost was too high compared to the ribbed dome solution.

What insulation benefits does the ribbed dome offer with hempcrete?

The ribbed dome, when integrated with hempcrete, provides excellent insulation. With up to 14 inches of hempcrete, the dome achieves an R39 value, which is ideal for Florida’s climate. This provides insulation against heat and cold, and also moderates temperature fluctuations while offering sound insulation.

What is the required insulation value for roofs and walls in Florida according to code?

In Florida, the building code requires a roof insulation value of R39, while the walls require a lower R-value, typically around R7 to R9.