Building a cordwood house involves laying log ends transversely within a mortar matrix, creating thick, insulated, and structurally sound walls. Key resources include Rob Roy's Essential Cordwood Building and Earthwood (often available as PDF/ebooks), which detail using lime-based mortar, sawdust insulation, and post-and-beam frameworks. Walls are typically 12-24 inches thick, with 40-60% wood.
Key Steps and Techniques for Cordwood Construction
- Materials: Use debarked, seasoned softwood (white cedar, pine, or spruce) to prevent shrinkage gaps.
- Mortar Mix: A recommended mix is 5 parts sand to 1 part lime putty, which allows the wall to "breathe" better than pure cement.
- Wall Construction: Apply two parallel mortar beds on the exterior and interior, leaving a gap in the center for insulation (sawdust/lime mixture) to create a thermal break.
- Layout: Logs are laid like bricks, with smaller pieces filling gaps to ensure a tight, visually appealing finish.
- Framework: Using a timber frame (post and beam) is recommended, as it allows the roof to be built first, protecting the walls during construction.
- Moisture Management: The mortar should be kept moist during curing to prevent cracking, and logs should slope slightly outward to drain water away.
Essential Resources/PDFs
- Essential Cordwood Building by Rob Roy: A comprehensive, step-by-step guide from a leading expert.
- Cordwood Construction by Appalachia-Science in the Public Interest: A detailed pamphlet outlining best practices, including log preparation.
- Scribd Cordwood Construction PDF: Overview of techniques and drying requirements for wood.
Tips for Success
- Plan for Utilities: Run electric and plumbing through the insulation cavity before finalizing the walls.
- Include "Bottle Ends": Incorporate glass bottles into the walls to add natural light and artistic flair.
- Seasoning: Ensure wood is dried for at least a year to prevent significant shrinkage.
