Chimney Liner Installation

Why this matters

Chimney lining is the highest-margin repair in chimney sweep work. Installations per chimney; multi-flue projects +. The customer pays because (1) safety: a degraded chimney is a fire + carbon monoxide risk; (2) code: many jurisdictions require lining for fuel conversion (gas to oil) or unlined chimneys; (3) insurance: many carriers require chimney inspection + lining for fireplaces in pre-1970 homes. Done correctly, a stainless liner outlasts the chimney. Done poorly, it fails the inspection + the customer pays twice.

When chimney needs new lining

Replacement triggers:

• Deteriorated existing clay tile liner (cracks, gaps, displaced tiles)
• Unlined chimney serving any modern appliance (most jurisdictions require lining)
• Fuel conversion: oil to gas, OR coal to oil, OR open fireplace to gas insert (each often requires specific liner)
• Heater installation that creates undersize / oversize venting issue
• Multiple appliances on same chimney (each typically gets own liner)
• Cracked / spalled brick where moisture enters chimney
• Chimney fire damaged the existing liner

Inspection triggers:

• Sweeping + finding tile gap with combustible material visible
• Customer reports backdrafting, smoke, soot
• Carbon monoxide alarm cycles when chimney in use
• Pre-purchase home inspection notes "unlined" OR "deteriorated lining"

Liner types

Stainless steel - the modern standard

• 304-grade (for wood, oil): most common; 25 - 50 year warranty
• 316Ti or 316L (for gas, modular): titanium-stabilized; resistance to acidic gas combustion byproducts
• 904L (rare, for high-acid corrosive environments): premium
• Flexible OR rigid sections (flexible easier to install in unusually-shaped chimneys)
• Insulated double-wall OR single-wall (insulation requires for wood typically)

Cast-in-place liner

• Specialty: poured ceramic liner inside existing chimney
• Used when chimney can't accept a tube (irregular profile, severe damage)
• More expensive, specialty contractor
• Brand: Solid Flue Systems

Tile (clay) liner

• Traditional; legacy
• Installed when chimney built; not retrofittable easily
• 25 - 50 year typical life
• Disadvantage vs stainless: less acid-resistant; cracks from heat shock
• Modern installs usually choose stainless over tile

Aluminum liner

• ONLY for gas appliances (low temp); illegal for wood OR oil OR coal
• Cheaper; shorter life
• Avoid unless specifically gas-only

Pre-installation requirements

Inspection + video scope

• Inspect entire flue with video camera (CSIA-recommended)
• Document damage; photos / video archived
• Measure flue size + length
• Identify offsets (chimney bends - flexible liner navigates these)
• Identify chimney chase access at top + bottom

Chimney structure assessment

• Solid masonry vs damaged
• Crown condition (some need rebuilding before lining)
• Cap presence
• Smoke chamber condition (firebox above damper)

Permit + code

• Most jurisdictions require building permit for chimney relining
• Local code identifies acceptable liner materials
• Customer's home insurance may require post-install inspection

Sizing the liner

Wood-burning fireplace + insert

• Liner size matches insert manufacturer requirement
• Typically 6" diameter
• Insulated liner recommended for any cold-climate install

Gas insert / appliance

• Per manufacturer specification (usually 4" or 5.5" diameter)
• Specific gas-rated liner (often Type B venting allowed inside lined chimney)

Wood-burning open fireplace

• Liner cross-sectional area = 1/10 to 1/12 of fireplace opening area
• Common: 6" round (28.3 sq inches) for moderate fireplaces; 8" round (50.3 sq inches) for larger

Oil burner

• Stainless 304 or 316
• Sized to oil burner manufacturer

Installation procedure (flexible stainless liner)

Step 1: Prepare chimney

1. Sweep chimney thoroughly (separate sweep visit OR same-day)
2. Remove old liner sections if present
3. Inspect chimney walls
4. Clean any creosote, soot, debris

Step 2: Build the liner

1. Cut flex liner to required length (chimney + offset + connection allowances)
2. Pre-attach top termination (rain cap + adapter)
3. Pre-attach bottom termination (appliance adapter)
4. Insulation wrap if specified (rope insulation OR ceramic blanket sheath)
5. Foil-tape or wire-tied insulation to liner

Step 3: Lower from top

1. From roof, drop the bottom termination FIRST into chimney
2. Helper at appliance base receives + guides
3. Two-person operation: top + bottom coordinate
4. Navigate offsets carefully - flexible liner bends but don't kink
5. Bottom termination exits at appliance connection

Step 4: Connect at bottom

1. Slip appliance-side connector into liner adapter
2. Secure with screws OR clamps per manufacturer
3. Connector to appliance (insert collar / oil burner outlet / stove pipe)
4. Sealed connection (high-temp sealant)

Step 5: Cap at top

1. Top termination plate seals to crown
2. Rain cap installed
3. High-temp silicone OR mortar at the seal
4. Verify watertight

Step 6: Insulate annular space (if not pre-insulated)

1. Pour or pump perlite OR vermiculite into the space between liner + chimney walls
2. Provides thermal insulation
3. Some installers use a "drop bag" to lower insulation in a controlled column

Step 7: Test

1. With stove cold, test draft with smoke pencil OR flame
2. Light a fire (or trigger appliance)
3. Verify proper draft + no smoke spillage
4. Verify no leak at any connection
5. CO meter reading at appliance + room

Step 8: Document

1. Photo: liner installed, terminations sealed, appliance connected
2. Test results
3. Customer review + sign-off
4. Warranty information transferred

Common issues

• Sized too small: insufficient draft + smoke spillage. Resize + reinstall.
• Sized too large: slow warm-up + gas condensation. Size to appliance.
• Insulation insufficient: cold liner = condensation + creosote. Always insulate.
• Top termination loose: water infiltration; re-seal.
• Bottom connection leak: smoke / CO into living space; re-seal with high-temp silicone.
• Liner kinked: reduces flow + traps creosote. Replace; don't straighten.

References

• NFPA 211 (Standard for Chimneys, Fireplaces, Vents + Solid Fuel Burning Appliances)
• CSIA (Chimney Safety Institute of America) standards
• Manufacturer install guides: DuraVent, ICC, Selkirk, Heat-Fab, Olympia
• Local building code + AHJ requirements
• Manuall internal: Annual Chimney Inspection SOP, Fireplace Insert Installation