Sovereignty Module: Set in Stone
Complete Masonry and Stonework: From Quarry to Cathedral
Stone outlasts all other building materials. This campaign covers stone identification, quarrying, cutting, mortar making, wall construction, arches, and the principles that make stone structures last millennia.
Chapter 1: Stone Types and Properties
| Stone | Hardness | Workability | Weather Resistance | Weight (lb/cu ft) | Best Use |
|---|---|---|---|---|---|
| Granite | Very hard | Difficult | Excellent | 165 | Foundations, monuments, paving |
| Limestone | Medium | Good | Good (varies) | 150 | Walls, carving, lime production |
| Sandstone | Soft-medium | Excellent | Moderate | 140 | Walls, carving, paving |
| Slate | Medium | Splits easily (cleavage) | Excellent | 170 | Roofing, flooring, writing |
| Marble | Medium | Good | Poor (acid rain) | 160 | Interior, carving, decoration |
| Basalt | Very hard | Very difficult | Excellent | 180 | Foundations, road base |
| Fieldstone | Variable | Use as-found | Variable | Variable | Walls, foundations (random) |
| Flint/chert | Very hard | Knappable (fractures) | Excellent | 155 | Tools, fire-starting, decoration |
Stone selection for building: 1) Local stone is always cheapest (transport is the major cost). 2) Bedding planes must be horizontal in walls (stone is strongest perpendicular to bedding). 3) Test weathering: existing old buildings show how local stone ages. 4) Harder = more durable but harder to shape. 5) Softer = easier to work but may weather faster. 6) Best compromise: medium limestone or sandstone for walls, hard granite for foundations.
Chapter 2: Quarrying and Shaping
| Method | Stone Type | Tools | Speed | Precision | Difficulty |
|---|---|---|---|---|---|
| Splitting (wedges) | Any with grain | Wedges, hammer, drill | Slow | Moderate | Moderate |
| Plug and feather | Granite, hard stone | Drill, plugs, feathers | Very slow | High | High |
| Sawing | Soft-medium stone | Stone saw + sand/water | Slow | Very high | Moderate |
| Hammer dressing | Any | Point chisel, hammer | Moderate | Moderate | Moderate |
| Pitching (rough shaping) | Any | Pitching tool, hammer | Fast | Low | Low |
| Fire splitting | Any | Fire + cold water | Fast | Very low | Low |
Wedge splitting: 1) Drill line of holes along desired split (6-8 inches apart, 2-4 inches deep). 2) Insert wedges (metal wedges between two thin metal shims/feathers). 3) Tap each wedge in sequence (light taps, rotate through all). 4) Repeat passes (each tap advances split slightly). 5) Stone splits along hole line. 6) For large blocks: holes closer together and deeper. 7) Natural grain/bedding helps — split WITH the grain when possible.
Chapter 3: Mortar and Cement
| Type | Ingredients | Strength | Set Time | Flexibility | Best For |
|---|---|---|---|---|---|
| Mud mortar | Clay + straw + water | Low | Days (drying) | High | Temporary, interior |
| Lime mortar | Lime putty + sand (1:3) | Moderate | Weeks-months | Good | Traditional masonry |
| Hydraulic lime | Hydraulic lime + sand | Moderate-high | Days-weeks | Moderate | Wet conditions, foundations |
| Portland cement | Cement + sand (1:3) | Very high | Hours-days | Very low | Modern construction |
| Roman concrete | Lime + volcanic ash + aggregate | High | Weeks | Moderate | Underwater, massive structures |
Lime mortar production: 1) Burn limestone at 1,650°F+ for days (lime kiln) → produces quickite (calcium oxide). 2) Slake quicklime: add water carefully (violent exothermic reaction) → lime putty (calcium hydroxide). 3) Age putty minimum 3 months (improves workability — traditional: years). 4) Mix: 1 part lime putty to 3 parts clean sharp sand. 5) Add water to workable consistency. 6) Use within hours of mixing. 7) Cures by absorbing CO₂ from air (carbonation) — takes weeks to months for full strength. 8) Advantage over cement: self-healing (micro-cracks re-seal), breathable, flexible, repairable.
Chapter 4: Wall Construction
| Wall Type | Thickness | Mortar | Skill Level | Speed | Strength | Lifespan |
|---|---|---|---|---|---|---|
| Dry stone (no mortar) | 18-36 inches | None | High | Slow | Good (gravity) | Centuries |
| Rubble (random stone + mortar) | 18-24 inches | Lime or cement | Moderate | Moderate | Good | Centuries |
| Coursed rubble | 18-24 inches | Lime or cement | Moderate-high | Moderate | Very good | Centuries |
| Ashlar (cut stone) | 12-18 inches | Lime (thin joints) | Very high | Very slow | Excellent | Millennia |
| Cavity wall (two skins) | 12-16 inches total | Lime or cement | High | Slow | Good + insulation | Centuries |
Dry stone wall principles: 1) Foundation: dig trench to solid ground, largest stones at base. 2) Two faces: build two outer faces that lean slightly inward (batter). 3) Hearting: fill center with small stones (tightly packed). 4) Through stones: long stones spanning full width every 3-4 feet (ties faces together). 5) Break joints: never stack vertical joints (each stone bridges joint below). 6) Capstones: heavy stones on top (weight holds wall together). 7) No mortar needed — gravity and friction hold everything. 8) Properly built: lasts centuries without maintenance.
Chapter 5: Arches and Vaults
| Type | Span Possible | Difficulty | Centering Required | Thrust | Use |
|---|---|---|---|---|---|
| Flat arch (lintel) | 3-6 feet | Low | Minimal | Vertical only | Doors, windows |
| Round arch (semicircular) | 6-30 feet | Moderate | Full semicircle | Outward + down | Bridges, doorways |
| Pointed arch (Gothic) | 10-60 feet | High | Two arcs | Less outward thrust | Cathedrals, large spans |
| Barrel vault | Length unlimited | Moderate-high | Full length | Continuous outward | Tunnels, cellars |
| Groin vault | Square bays | High | Diagonal ribs | Corner points | Large rooms |
| Corbelled arch | 3-10 feet | Low | None (self-supporting during build) | Minimal | Primitive, small spans |
Arch construction: 1) Build centering (temporary wooden form in arch shape). 2) Set springer stones (first stones on each side, on solid support). 3) Build up both sides simultaneously (keeps weight balanced). 4) Each stone (voussoir) is wedge-shaped (wider on outside). 5) Set keystone last (top center stone that locks arch). 6) Remove centering (arch is now self-supporting). 7) Key principle: arch transfers weight outward and down to supports (abutments must resist lateral thrust).
Reference Card
- Foundation is everything (stone walls on poor foundations crack and lean — dig to solid ground). 2. Break all joints (never align vertical joints — each stone must bridge the gap below). 3. Batter inward (walls that lean slightly inward resist tipping — 1 inch per foot of height). 4. Through stones tie (long stones spanning full wall width prevent face separation). 5. Lime mortar breathes (cement traps moisture and damages old stone — use lime for repair). 6. Arches are self-supporting (once the keystone is set, remove centering — gravity holds it). 7. Drain water away (water is stone's enemy — cap walls, slope surfaces, provide drainage). 8. Local stone is best (transport costs more than material — use what's nearby).