
○ Area: Approximately 314 square feet (π × 10²).
○ Gravel Volume: 314 × 0.5 ≈ 157 cubic feet (~5.8 cubic yards). It’s wise to
order around 6 cubic yards.
Vapor Barrier and Moisture Control
A vapor barrier is a critical component of any foundation to prevent moisture from migrating
up from the ground, which can lead to mold, mildew, and damage to the structure.
Incorporating a vapor barrier is highly recommended for all Zomes foundation types to
ensure long-term structural integrity and a healthy interior environment.
General Guidelines
● Material: Use a high-quality, 6-mil or greater polyethylene plastic sheeting (vapor
barrier).
● Sealing: Ensure all seams and penetrations (e.g., utility lines) are overlapped by at
least 6-12 inches and sealed with a specialized vapor barrier tape to create an
airtight and watertight seal.
Specific to Foundation Types
● For Compacted Gravel Base:
○ Installation: Lay the vapor barrier over the entire compacted gravel base.
○ Perimeter: Run the sheeting up the vertical perimeter of the foundation and
secure it so it can be integrated with the wall panels later, creating a
continuous moisture break.
● For Post and Beam Foundation (Crawl Space):
○ Installation: Lay the barrier across the ground within the crawl space.
Overlap and seal seams as described in the general guidelines.
○ Considerations: Ensure that the crawl space has adequate ventilation as
required by local codes, or consider a fully sealed (encapsulated) crawl space
system for superior moisture control.
Additional Considerations
● Slope and Drainage: Grade the gravel base so that water drains away from the
structure. A slight crown (higher in the center) helps ensure runoff.
● French Drain: If drainage is a concern, install a French drain around the perimeter.
This is especially important in low-lying or high-rainfall areas.
● Compaction Check: After compaction, test the firmness of the gravel by walking
over it. There should be minimal movement underfoot.
By following these detailed guidelines for either the post and beam or the gravel base
foundation, you’ll ensure that your Zomes is built on a stable, durable base tailored to your
specific site conditions. Always refer to local building codes and consider consulting a
professional engineer when making structural decisions.