# Sovereignty Module: Raise the Flue

## Complete Chimney and Fireplace Construction: From Foundation to Draft

A properly built chimney transforms a shelter from smoky cave to comfortable home. This campaign covers fireplace design, chimney construction, draft principles, and maintenance.

### Chapter 1: Fireplace Design

| Type | Heating Efficiency | Complexity | Materials | Best For |
|---|---|---|---|---|
| Open fireplace (Rumford) | 15-25% | Moderate | Stone, brick, mortar | Heating, ambiance |
| Enclosed fireplace (masonry heater) | 70-90% | High | Firebrick, mortar | Primary heating |
| Rocket mass heater | 80-90% | Moderate | Cob, firebrick, barrel | Efficient heating |
| Franklin stove (open front) | 30-40% | High (casting/welding) | Cast iron or steel | Heating, cooking |
| Simple hearth (no chimney) | 5-10% | Very low | Stone | Emergency, outdoor |

Rumford fireplace dimensions: 1) Opening width: 24-48 inches (match room size). 2) Opening height: 2/3 to 3/4 of width. 3) Depth: 1/3 of width (shallow for maximum heat reflection). 4) Back wall width: 1/3 of opening width. 5) Back wall angled forward (reflects heat into room). 6) Side walls angled inward (funnel heat outward). 7) Throat: narrow opening above firebox (4 inches deep). 8) Smoke shelf: flat area behind throat (prevents downdraft). 9) Damper: adjustable plate at throat (controls draft). 10) Flue: rises from smoke shelf to chimney top.

### Chapter 2: Chimney Construction

| Material | Durability | Heat Resistance | Cost | Difficulty |
|---|---|---|---|---|
| Brick (fired clay) | Excellent | Very good | Moderate | Moderate |
| Stone (natural) | Excellent | Good | Low (if local) | Moderate-high |
| Cob (clay/sand/straw) | Good | Moderate | Very low | Low |
| Concrete block | Good | Moderate | Moderate | Low-moderate |
| Metal pipe (stovepipe) | Moderate | Good (stainless) | Moderate | Low |

Brick chimney construction: 1) Foundation: concrete pad extending 4 inches beyond chimney on all sides. 2) Firebox: firebrick laid with fire clay mortar (withstands direct flame). 3) Chimney walls: minimum 4 inches thick (standard brick). 4) Flue liner: clay tile liner inside chimney (protects brick from heat and creosote). 5) Flue size: minimum 1/10 of fireplace opening area. 6) Chimney height: minimum 3 feet above roof penetration. 7) Chimney must extend 2 feet above any structure within 10 feet. 8) Cap: concrete or stone cap with drip edge (prevents rain entry). 9) Spark arrestor: wire mesh screen at top (prevents ember escape). 10) Cricket (saddle): small peaked structure on uphill side of chimney (diverts water).

### Chapter 3: Draft Principles

| Factor | Effect on Draft | Optimal Range | Problem If Wrong |
|---|---|---|---|
| Chimney height | Taller = stronger draft | 15-25 feet minimum | Short chimney: poor draft, smoke in room |
| Flue temperature | Hotter = stronger draft | 250-500°F at top | Cold flue: weak draft, creosote buildup |
| Flue size | Must match firebox | 1/10 of opening area | Too large: sluggish; too small: smoking |
| Air supply | Must have combustion air | Fresh air intake | Sealed house: negative pressure, backdraft |
| Wind | Can help or hinder | Chimney above roofline | Below roofline: downdraft |
| Damper position | Controls draft | Partially open to full | Closed: smoke fills room; full open: heat loss |

Draft troubleshooting: 1) Smoke enters room: check damper (open?), check chimney height, check for obstructions. 2) Cold start problems: pre-heat flue with newspaper torch before lighting main fire. 3) Downdraft in wind: chimney may be too short or in wind shadow. 4) Creosote buildup: burn hotter fires, ensure adequate air supply. 5) Negative pressure: modern sealed houses may need dedicated combustion air intake.

### Chapter 4: Rocket Mass Heater

| Component | Material | Function | Size |
|---|---|---|---|
| Feed tube | Firebrick | Fuel input | 6x6 inch opening |
| Burn tunnel | Firebrick | Primary combustion | 6x6 inch, 12-18 inches long |
| Heat riser | Insulated firebrick or metal | Secondary combustion | 6x6 inch, 3-4 feet tall |
| Barrel (bell) | 55-gallon steel drum | Heat exchange | Standard drum |
| Exhaust ducting | 6-8 inch stovepipe | Heat extraction | 20-40 feet through thermal mass |
| Thermal mass (bench) | Cob, brick, stone | Heat storage | Bench shape, 6-12 inches thick |

### Chapter 5: Maintenance

| Task | Frequency | Purpose | Method |
|---|---|---|---|
| Chimney sweep | Annually (minimum) | Remove creosote | Chimney brush, top-down |
| Inspect mortar joints | Annually | Prevent gas leaks | Visual, repair with mortar |
| Check cap and screen | Annually | Prevent water/animal entry | Visual, replace if damaged |
| Inspect flue liner | Every 2-3 years | Prevent chimney fire | Visual from top and bottom |
| Ash removal | Weekly during use | Maintain airflow | Shovel, metal bucket |
| Damper check | Before each season | Ensure operation | Open/close, lubricate |

### Reference Card

1. The Rumford fireplace is shallow (a shallow firebox with angled walls reflects more heat into the room; deep fireplaces send most heat up the chimney). 2. The throat controls everything (a narrow throat above the firebox accelerates smoke upward and creates strong draft; too wide and draft is weak). 3. Chimney height creates draft (hot air rises; a taller chimney creates stronger draft; minimum 15 feet from firebox to chimney top). 4. The flue must match the firebox (flue cross-section should be 1/10 of the fireplace opening area; too large or too small causes smoking problems). 5. Pre-heat the flue on cold starts (a cold chimney has no draft; hold a lit newspaper in the firebox for 30 seconds to establish upward flow before lighting the fire). 6. Creosote is the enemy (incomplete combustion deposits creosote in the flue; creosote is flammable and causes chimney fires; burn hot, clean fires and sweep annually). 7. A rocket mass heater is 80-90% efficient (the insulated heat riser creates complete combustion; exhaust ducting through a thermal mass bench captures nearly all remaining heat). 8. Never use a chimney without a cap (rain, snow, animals, and debris enter an uncapped chimney; a cap with spark arrestor screen is essential).