Covering log walls requires careful consideration of materials to manage moisture and ensure the long-term health of the structure.
The best way to cover log walls often involves selecting breathable materials to prevent moisture problems.
Why Consider Covering Log Walls?
While often appreciated for their natural aesthetic, log walls might be covered for various reasons, including:
- Improving Energy Efficiency: Adding exterior covering and insulation can enhance thermal performance.
- Protecting Logs: Shielding logs from harsh weather, UV rays, and pests can prolong their lifespan.
- Changing Appearance: A different siding can update the look of a log structure.
- Addressing Moisture Issues: Proper covering with a suitable system can help manage moisture.
Choosing the Right Materials: Focus on Breathability
When covering log walls, it is crucial to use materials and systems that allow the wall to breathe. This means allowing moisture vapor to escape from the wall assembly to the outside. The reference specifically recommends materials other than steel siding because they are more breathable.
Key Insight from Reference:
"I recommend using something other than steel siding such as cement board or cedar, which are more breathable products. The more breathable the wall is, the less likely that you will develop problems due to moisture building up in your log walls."
- Breathable Materials: Materials like cement board and cedar are highlighted as good options due to their breathability.
- Avoiding Non-Breathable Options: Materials like steel siding are discouraged because they can trap moisture.
Recommended Breathable Covering Options
Based on the importance of breathability, here are recommended materials:
- Cement Board Siding:
- Pros: Durable, fire-resistant, resistant to pests, can be painted, relatively breathable.
- Considerations: Requires careful installation, can be heavy.
- Cedar Siding:
- Pros: Naturally resistant to decay and insects, aesthetically pleasing, highly breathable, sustainable option.
- Considerations: Requires periodic maintenance (staining/sealing), can be more expensive than other options.
- Wood Siding (other than cedar):
- Pros: Variety of styles and finishes, can be breathable depending on type and finish.
- Considerations: Requires proper treatment and maintenance, breathability can vary.
Importance of a Building Envelope System
Regardless of the covering material chosen, covering log walls typically involves creating a complete wall assembly or "building envelope." This system usually includes:
- The Original Log Wall: The base structure.
- Air/Vapor Barrier: A layer applied to the interior side (warm side in cold climates) to control vapor diffusion, or carefully managed on the exterior depending on climate and wall assembly design. Crucially, the exterior layers must allow vapor to escape.
- Insulation: Adding exterior insulation between the logs and the new siding improves energy efficiency.
- Water-Resistive Barrier (WRB): Applied over the logs/insulation to protect against bulk water intrusion. This layer must be vapor-permeable (breathable).
- Ventilation Gap (Rainscreen): Creating a gap between the WRB and the siding allows air circulation, helping to dry the siding and the wall assembly. This is vital for breathability.
- Exterior Siding: The chosen covering material (e.g., cement board, cedar).
Why is Moisture Management Critical?
Moisture buildup within a log wall assembly can lead to significant problems:
- Rot and Decay: Trapped moisture can cause the log structure to rot, compromising structural integrity.
- Mold and Mildew: These can grow in damp conditions, affecting air quality and causing health issues.
- Pest Infestations: Rotting wood attracts insects like termites and carpenter ants.
- Reduced Insulation Effectiveness: Wet insulation loses its ability to resist heat flow.
By using breathable materials like cement board or cedar and incorporating proper WRBs and ventilation gaps, you ensure that any moisture that gets into or through the wall can dry out, preventing these issues.
Summary Table: Covering Log Walls
| Aspect | Recommendation | Why |
|---|---|---|
| Material Choice | Use breathable options like cement board, cedar. | Prevents moisture buildup within the wall. |
| Materials to Avoid | Avoid non-breathable materials like steel siding. | Can trap moisture, leading to rot and other problems. |
| Assembly Design | Incorporate WRB and ventilation gap (rainscreen). | Protects from bulk water and allows wall assembly to dry out (breathe). |
| Moisture Control | Design for vapor permeability on the exterior. | Ensures moisture can escape from the wall. |
Covering log walls effectively requires prioritizing breathability in material selection and wall assembly design to protect the underlying logs from moisture damage. Consulting with a professional experienced in log home renovations and building envelope science is highly recommended for specific project planning.
