Chimney Relining Decision and Process
Why this matters
Chimney relining is one of the higher-cost chimney services. The decision to reline is significant - affecting cost, time, and the customer's chimney functionality. Understanding when relining is needed, what options exist, and how to communicate this to the customer is part of professional chimney sweep practice.
When relining is needed
| Trigger | Detail |
|---|---|
| Cracked or damaged clay tiles | Liner integrity compromised |
| Gaps between tiles (mortar failed) | Combustion gases can leak between tiles |
| Severe creosote (Stage 3) | Sometimes the liner can't be cleaned safely |
| Liner sized wrong for the appliance | Switching from open fireplace to insert often needs new size |
| Liner deteriorated by age | Older chimneys may have failed liners |
| Chimney fire damage | Liner often damaged in fires |
| Inadequate draft | Wrong size causing flow issues |
The trigger determines the urgency.
Liner types
Clay tile liner (traditional)
- Standard residential masonry chimney
- 8-inch round or 12x12 square typical
- Long-lasting (50+ years) when intact
- Cracks from age, frost, fire
- Difficult to repair; usually replaced
Stainless steel liner
- Modern standard for relining
- Single-wall or double-wall (insulated)
- Flexible OR rigid
- 30+ year service life
- Common for residential relining
Cementitious liner
- Pumped into the chimney; cures in place
- Forms a new liner inside the old
- Used for historic chimneys; preserves the masonry exterior
- Specialty; expensive
Pumice liner
- For specialty applications
- Less common in US
For most residential relining: stainless steel.
Sizing
The new liner must match the appliance:
| Appliance | Required liner size |
|---|---|
| Open fireplace | 12-1/2% to 13% of fireplace opening area; varies |
| Wood stove insert | Per manufacturer's appliance |
| Pellet stove | Per manufacturer's appliance |
| Gas appliance | Per manufacturer's appliance |
| Multi-appliance | Each appliance separately |
Manufacturer specifications apply. Sizing must match the appliance for proper draft.
Installation procedure
For stainless steel relining:
Step 1: Inspection + planning
- Verify the chimney's interior dimensions
- Identify the path (any bends, obstructions)
- Calculate the required liner length
- Determine the appliance + sizing
- Quote the work
Step 2: Preparation
- Remove the chimney cap (if present)
- Clean the existing flue
- Verify the chimney's structural integrity
- Set up scaffolding / safety equipment
Step 3: Liner installation
For rigid stainless steel:
- Insert sections from the top
- Push down through the chimney
- Connect at the bottom to the appliance / firebox
For flexible stainless steel:
- Pull from the top down (with cable + winch)
- Position properly
- Connect at both ends
Step 4: Insulation (if double-wall)
For insulated liners:
- Insert the insulation around the liner
- Pack to fill the gap between liner + chimney
- Heavy insulation = better draft + warmer flue
Step 5: Connection
- Connect the liner to the appliance / firebox
- Verify proper sealing
- Cap the top of the chimney + liner
Step 6: Verification
- Inspect with camera
- Verify no gaps, kinks, or damage
- Run a test fire (after appropriate cooldown if needed)
- Verify proper draft
Time required
For typical residential relining:
- Single-wall stainless: 4-8 hours
- Double-wall (insulated): 6-10 hours
- Cementitious: 1-2 days
- Complex installations: longer
The customer should plan for the time.
Cost considerations
Relining is significant:
| Component | Cost basis |
|---|---|
| Liner materials | Per linear foot; varies by type |
| Insulation (double-wall) | Additional |
| Cap | Replacement typically |
| Labor | Hourly; specialty work |
| Permits + inspection | Some jurisdictions |
| Cleanup | Usually included |
For most residential: relining is in the thousands of dollars. The customer's understanding of the value matters.
When to recommend
| Customer situation | Recommendation |
|---|---|
| Customer says "fireplace doesn't work right" | Inspection first; relining is one option |
| Damaged clay liner found at inspection | Relining; preserve the chimney structure |
| Converting from fireplace to wood stove | Relining typically required |
| Existing pellet / wood stove with marginal draft | Relining may help |
| After a chimney fire | Often required |
| Old chimney with multiple liner issues | Relining preserves the chimney |
For some customers, relining is the only way to safely use the chimney.
When NOT to recommend
If the chimney itself has structural issues:
- Severe masonry deterioration
- Foundation issues
- Crown failure beyond repair
- Multiple issues exceeding the liner
A rebuilt OR replaced chimney may be the answer, not relining. The chimney structure must support the new liner.
Inspection before quoting
The Level 2 inspection is the standard before quoting relining:
- Camera inspection of the entire flue
- Documentation of the issues
- Photo of the issues
- Measurement of dimensions
- Identification of the existing liner type + condition
- Identification of any structural issues
The customer's quote is based on the inspection findings.
Documentation
For each relining job:
- Inspection findings
- Liner specifications (material, size, insulation)
- Appliance information
- Installation date
- Code compliance verification
- Manufacturer warranty information
- Customer training on operation
- Photo documentation
- Customer file note
Warranty
For stainless steel liners:
- Manufacturer warranty: 5-30 years (varies)
- Installer warranty: 1-5 years (varies)
- Coverage: defects + premature failure
- Excluded: misuse, lack of maintenance, fire damage
Inform the customer of the warranty terms.
Customer education
For relining customers:
- "Your new liner extends your chimney's safe use"
- "Annual inspection + sweep is essential to protect the warranty"
- "Use the appliance per its specifications"
- "If you have any unusual issues, call us"
Sizing relining for HVAC appliances
Beyond fireplaces:
| Appliance | Liner type |
|---|---|
| Gas furnace | Specific stainless; sized per appliance |
| Gas water heater | Same |
| Boiler | Same |
| Oil-fired | Different specifications |
| Combination (multiple appliances) | Specific sizing per IBC |
Each appliance has specific requirements. Some jurisdictions require code-compliant relining for HVAC venting.
Combined appliance relining
For multiple appliances sharing a chimney:
- Each appliance + its venting requirements
- Some can share a chimney; others require separation
- Liner sizing for the combination
- Code compliance critical
References
- NFPA 211 (Standard for Chimneys, Fireplaces, Vents)
- IRC R1003 (Chimneys)
- UL 1777 (Chimney Liners)
- UL 103 (Chimney Pipes)
- Manufacturer documentation (Olympia, Z-Flex, Forever Flex)
- CSIA training materials
- Manuall internal: Chimney Lining Install, Annual Chimney Inspection, Masonry Repair Options