Wall Construction

Part of Permanent Shelter

Walls define your shelter. They hold up the roof, keep out wind and rain, retain heat, and provide security. The wall system you choose depends on available materials, climate, and how long you need the structure to last. Every method described here has sheltered people for centuries — none are inferior, just suited to different conditions.

Structural Principles

Before building any wall, understand two fundamental concepts.

Load-Bearing vs. Frame Construction

Type	How It Works	Examples
Load-bearing	The walls themselves carry the weight of the roof. Every wall section supports what is above it.	Stone walls, cob, adobe, log
Frame	A skeleton of posts and beams carries the roof. Walls are infill that provide enclosure but not structural support.	Wattle-and-daub, timber frame with panel infill

Why it matters: You cannot remove a section of a load-bearing wall to add a door or window after construction without risking collapse. Plan all openings before you start building. Frame construction is more forgiving — you can modify infill walls without affecting structural integrity.

Wall Thickness and Insulation

Thicker walls insulate better, but the material matters more than the thickness:

Wall Material	Minimum Thickness for Adequate Insulation	Notes
Log	20-25 cm (8-10 in)	Good insulator; gaps between logs need chinking
Stone	45-60 cm (18-24 in)	Poor insulator — stores heat but conducts it. Use double-wall with fill.
Cob	40-50 cm (16-20 in)	Moderate insulator; thermal mass stores daytime heat
Wattle-and-daub	15-20 cm (6-8 in)	Poor insulator alone — add interior clay plaster and exterior limewash
Adobe brick	30-40 cm (12-16 in)	Excellent thermal mass for hot climates with cold nights

Thermal Mass vs. Insulation

Thermal mass (stone, cob, adobe) absorbs heat during the day and releases it at night. This is ideal in climates with hot days and cold nights. Insulation (wood, straw, dried moss packed in walls) slows heat transfer. In cold climates with long winters, insulation matters more than thermal mass.

Wall Types

Log Walls

The classic frontier shelter. Logs stack horizontally, notched at the corners to interlock.

Best for: Forested areas with straight conifers. Cold climates.

Build process:

1. Select logs of uniform diameter (15-25 cm / 6-10 in). Debark them — bark traps moisture and harbors insects.

2. Lay the sill logs on your foundation. These must be your straightest, most rot-resistant logs. Place a moisture barrier (bark strips, flat stones) between foundation and sill.

3. Notch the corners. The simplest joint is the saddle notch: scoop a curved notch from the underside of the upper log so it sits snugly on the lower log. The notch should face downward so rain cannot pool in it.

4. Stack and alternate. Each course alternates the butt (thick) and tip (thin) ends at each corner to keep the wall level as it rises.

5. Chink the gaps. Stuff moss, clay, or a mix of clay and straw between logs to seal against wind. Press it firmly into every crack.

6. Allow for settling. Green logs shrink as they dry. Leave 5-8 cm (2-3 in) of extra space above door and window frames, filled loosely with chinking. The wall will compress downward over the first year.

Green vs. Seasoned Logs

Green (freshly cut) logs are easier to work but shrink 5-10% as they dry. This opens gaps in walls and loosens joints. Ideally, debark logs and let them dry for 3-6 months before building. If you must build immediately, plan to re-chink all gaps after the first winter.

Stone Walls

Permanent, fireproof, and nearly indestructible when built correctly.

Best for: Areas with abundant stone. Any climate, with sufficient wall thickness.

Build process:

1. Build on a continuous stone foundation that is wider than the wall above.

2. Lay stones in courses, following the two-over-one rule (each stone bridges the joint between two below). Use mortar between courses if available.

3. Build two faces with a rubble core. The inner and outer wall faces should be flat and plumb. Fill the space between with smaller stones packed tightly with mortar or clay.

4. Place tie stones every 1-1.5 m that span the full wall thickness, locking the two faces together.

5. Maintain plumb — check vertical alignment frequently with a weighted string (plumb bob). Stone walls that lean even slightly will eventually fail.

Cob Walls

A monolithic mix of clay, sand, straw, and water, built up in layers without forms.

Best for: Areas with clay soil. Mild to moderate climates.

Build process:

1. Mix cob: approximately 60% sand, 25% clay, 15% straw by volume. Add water until the mix holds together when squeezed. Too wet and it slumps; too dry and it crumbles.

2. Place in lifts. Build up 30-45 cm (12-18 in) at a time, shaping by hand. Let each lift dry for 2-3 days before adding the next.

3. Knit the lifts together. Before a lift fully dries, rough up the top surface and poke holes into it. The next lift’s wet cob will bond into these textures.

4. Shape as you go. Cob can be sculpted — round windows, curved walls, built-in shelves. This is its greatest advantage over other methods.

5. Protect from rain. Cob dissolves in sustained rain. Wide roof overhangs (60+ cm / 24+ in) and a lime or clay plaster exterior are essential.

Wattle-and-Daub

A woven wood frame (wattle) plastered with a clay mix (daub). Used as infill between structural posts.

Best for: Frame structures, areas with flexible saplings and clay soil.

Build process:

1. Set vertical stakes (10-15 cm apart / 4-6 in) between your structural posts, driven into a groove in the sill beam.

2. Weave horizontal withies (flexible branches — willow, hazel, or any green sapling) between the stakes, alternating over and under. Pack them tightly.

3. Mix daub: clay, sand, straw, and water in similar proportions to cob but wetter — it should be a thick paste you can push into the wattle.

4. Apply daub to both sides. Press it through the wattle from one side, then smooth the other. Build up to 3-5 cm (1-2 in) thickness on each side.

5. Let dry completely — this takes 1-3 weeks depending on climate. Cracks will appear. Fill them with more daub, then apply a finish plaster of fine clay or lime.

Adobe Brick

Sun-dried earth bricks laid up with mud mortar. A standardized, repeatable building unit.

Best for: Hot, dry climates. Flat terrain with clay soil.

Build process:

1. Make a brick mold — a simple wooden frame, typically 25 x 35 x 10 cm (10 x 14 x 4 in).

2. Mix adobe: similar to cob — clay, sand, and straw. Pack the mix firmly into the mold, then lift the mold away.

3. Dry in the sun for 3-5 days, turning bricks on edge after 2 days. Fully cured bricks ring when tapped together.

4. Lay bricks in courses with mud mortar (the same adobe mix, slightly wetter). Overlap joints between courses (running bond).

5. Plaster the finished wall inside and out with clay or lime plaster to protect from erosion.

Connecting Walls to Foundations

The joint between wall and foundation is a critical vulnerability.

• Sill beam connection: For wooden walls (log, frame), the sill beam must be fastened to the foundation. Drill or burn holes through the sill beam and drive wooden pegs into gaps between foundation stones. Alternatively, set anchor stones that protrude upward through notches in the sill.

• Masonry walls: The first course of the wall should be set in mortar on the foundation top, with stones or bricks overlapping the foundation edge by at least 5 cm on the interior side.

• Moisture barrier: Always place a moisture barrier (birch bark, overlapping flat stones, or packed clay) between the foundation and the wall’s first course.

Openings for Doors and Windows

Plan Openings Before Building

In load-bearing walls, every opening weakens the wall. You must install a lintel — a strong horizontal beam across the top of the opening that transfers the wall’s weight to the sides. Without a lintel, the wall above the opening will crack and eventually collapse.

Lintel sizing: The lintel must extend at least 20 cm (8 in) into the wall on each side of the opening. For openings wider than 90 cm (3 ft), use a lintel at least 15 cm (6 in) deep. Stone lintels work but are heavy and can crack — wooden lintels are more forgiving.

Bracing and Corner Connections

Corners are where walls meet, and they must be the strongest part of your structure.

• Log walls: Alternate the corner notches so each log locks the perpendicular wall in place. The interlocking pattern at corners is what gives a log structure its rigidity.

• Frame walls: Install diagonal braces from the sill beam to the top plate at every corner, at approximately 45 degrees. Without diagonal bracing, a frame structure will rack (lean sideways) under wind load.

• Masonry walls: Interlock corner stones by alternating long sides — one course has the long face running north-south, the next course has it running east-west. This toothing pattern bonds the two walls together.

Key Takeaways

• Choose your wall type based on available materials — log in forests, stone where rock is plentiful, cob and adobe where clay soil dominates.
• Understand load-bearing vs. frame before you start — it determines where you can place openings and how you must plan the build.
• Always install lintels above openings — no exceptions in load-bearing walls.
• Corners make or break the structure — invest your best materials and most careful work at every corner joint.
• Moisture barriers between foundation and walls extend the life of any wall system by years.
• Protect earth walls from rain — wide overhangs and plaster are not optional for cob, adobe, and wattle-and-daub.
• Plan for settling in log construction — green logs shrink, and you will re-chink after the first season.