Even after a fresh chimney cleaning, many homeowners in Lake Oswego, Portland, West Linn, Tigard, Tualatin, and the surrounding metro areas still experience a frustrating and sometimes alarming problem:
Smoke pouring back into the home instead of rising up the chimney.
If you’ve ever lit a fire and watched the smoke roll into your living room even after hiring a professional chimney sweep you’re not alone. Metro Chimney PDX receives these calls every single week, especially during:
- The first cold snap of the season
- Sudden changes in barometric pressure
- Heavy windstorms blowing through Lake Oswego and Portland
- Seasonal inversions, when cold air traps heavier smoke low in the flue
- The fall “burn season rush,” when fireplaces get used after months of being idle
Smoking fireplaces are extremely common but they’re also very misunderstood.
This guide explains, in detail, exactly why fireplaces smoke after a cleaning and what the real fixes are according to the decades of expertise at Metro Chimney PDX, the leading chimney sweep specialists serving the Lake Oswego and Portland metro region.
What Homeowners Think Causes Smoking (But Actually Doesn’t)
Let’s clear up a few common misconceptions:
Myth 1: Portland’s damp climate causes smoking fireplaces
No damp weather doesn’t cause creosote or make chimneys smoke. Creosote comes from liquids inside the wood (moisture, sap, oils), not from humidity or rain.
Myth 2: Insulation or sealed homes cause creosote
Not true. These do not cause creosote. They may, in rare cases, affect airflow, but they are not creosote creators.
Myth 3: Chimneys smoke because the cleaning wasn’t “deep enough”
A correctly done cleaning removes Stage 1 creosote only (which is the part brushes can remove).
If there was Stage 2 or Stage 3, it requires a completely different long-term process NOT more brushing.
Now let’s look at the real reasons your chimney smokes even after a proper cleaning.
1. The Smoke Shelf Wasn’t Vacuumed (Most Companies Skip This Step)
This is the #1 cause of smoking fireplaces Metro Chimney PDX sees in Lake Oswego and Portland.
Why it matters
The smoke shelf sits behind the damper. It’s a bowl-shaped area that catches:
- Soot
- Ash
- Debris
- Old creosote flakes
- Animal nesting material
If this area isn’t vacuumed, smoke circulation gets disrupted and the draft collapses.
Most companies skip it
Many Portland chimney companies stopped vacuuming smoke shelves around 2002 because:
- It takes extra time
- It requires specialized vacuums
- They realized they could squeeze in one more cleaning a day by skipping it
- They charge $250–$500 extra to do it as an “add-on”
Metro Chimney PDX, however, always vacuums the smoke shelf as part of every chimney cleaning no upcharge.
👉 Related Reading:
Why Vacuuming the Smoke Shelf Matters – The Step Most Portland Chimney Companies Skip
2. The Damper Isn’t Opening Fully
A half-open damper is like trying to breathe through a straw.
Even if your chimney is spotless, smoke will still come back inside if:
- The damper is warped
- The chain or handle is broken
- Creosote has caked around the hinge
- The plate isn’t lifting fully
- The wrong damper type was installed
Metro Chimney PDX frequently finds that the damper appears open to the homeowner but actually isn’t.
👉 Related guide:
What to Do When Your Fireplace Damper Breaks: A Portland Homeowner’s Guide
3. Stage 2 or Stage 3 Creosote Is Still Inside the Flue (Normal After a Standard Sweep)
This is one of the biggest misunderstandings in Oregon.
Stage 1 creosote can be brushed away
Cleaning removes:
- Loose soot
- Flakes
- Ash
- First-degree creosote
Stage 2 and Stage 3 creosote cannot be brushed out
Brushes glide over them they are too hard.
This doesn’t mean the chimney sweep did a bad job.
It means the chimney has buildup that cannot be removed with brushes, no matter how hard someone scrubs.
The ONLY safe way to remove Stage 2 & 3 creosote
Metro Chimney PDX:
- Does NOT sell gimmicky $4,000 “one-time creosote removal treatments”
- Does NOT use aggressive rotary chains that damage flue tile
Instead, Metro Chimney PDX:
Teaches the homeowner how to use the correct anti-creosote spray
→ Spray each piece of firewood with 10–12 squirts,
→ Wait 10 minutes,
→ Burn the log,
→ Repeat every fire.
Over weeks, this slowly converts hardened creosote into a non-flammable, non-acidic, brushable material that can be removed at the next cleaning.
If there is excessive Stage 2 or 3, the homeowner is placed on a 1–2 month burning regimen with detailed instructions.
👉 Related blog:
The Three Stages of Creosote: What Every Portland Homeowner Should Know
4. Negative House Pressure (Very Common in Modern Oregon Homes)
This is one area where local weather patterns DO matter but not in the way people think.
Your chimney is a vertical duct that relies on:
- Warm rising air
- Pressure differences
- Temperature contrast
When external conditions change quickly such as:
- A sudden cold snap
- A Portland winter inversion
- Heavy coastal pressure pushing inland
- A large storm system over Lake Oswego
The house can become negatively pressurized, pulling air down the chimney instead of up.
Things that worsen negative pressure:
- Bathroom fans
- Kitchen hoods
- Basement furnaces
- Tight-sealed windows
- Newly insulated attics
Lighting a fire while the home is negatively pressurized causes smoke to pour into the living room.
5. The Chimney Is Too Short
Some chimneys simply weren’t built tall enough.
By law, the top of the chimney must be at least:
- 2 feet above any structure within 10 feet,
- and a minimum of 3 feet above the roof.
Short chimneys fight against airflow, especially in Portland’s wind corridors.
Metro Chimney PDX often fixes smoking issues by extending the flue height.
6. Wind Is Hitting the Chimney the Wrong Way
Lake Oswego, West Linn, and Tigard all have neighborhoods with:
- Hillside elevation
- River valley winds
- Cross-current gusts from the Willamette
When wind travels over the roofline incorrectly, it can push air down into the chimney.
The Fix
Metro Chimney PDX installs the correct chimney cap depending on wind pattern:
- Standard cap for most homes
- High wind cap when wind downdrafts are detected
👉 Related blog:
Standard Chimney Cap vs. Wind Cap: Which Does Your Portland Home Need?
7. The Firewood Is Too Wet, Too Green, or the Wrong Type
Wet wood = cold fire = heavy smoke.
Firewood sold cheaply around Portland (especially after storms) is often:
- Not seasoned
- High moisture
- Full of sap
This causes incomplete combustion and excessive smoke even in a perfectly clean chimney.
8. The Firebox and Flue Don’t Match
If the fireplace opening is too large for the flue size, the draft will always struggle.
This is extremely common in:
- Older Lake Oswego homes
- Custom-built fireplaces
- Retrofits from the 1970s–90s
Metro Chimney PDX can identify this instantly and recommend correct solutions.
9. The Chimney Has Internal Damage You Can’t See
Internal structural issues can block smoke, including:
- Cracked flue tiles
- Misaligned flue joints
- Collapsed sections
- Old nesting material deep in the flue
A cleaning doesn’t fix structural damage. Only a chimney inspection can diagnose it.
10. The Fire Was Built Incorrectly
Yes technique matters.
- Too much small kindling
- Not enough airflow
- Logs packed too tightly
- Fire started without pre-heating the flue
Metro Chimney PDX often teaches homeowners how to build a proper fire for maximum draft.
How Metro Chimney PDX Fixes Smoking Chimneys (The Right Way)
Here’s the step-by-step approach:
- Full visual and physical inspection
- Vacuum smoke shelf thoroughly
- Verify damper is opening correctly
- Check flue height and code compliance
- Assess Stage 2/3 creosote levels
- Teach homeowner the anti-creosote spray regimen
- Identify negative pressure sources
- Evaluate need for standard or high-wind cap
- Check for structural issues
- Provide 100% transparent pricing
No gimmicks. No “one-time” miracle treatments. No upsells.
FAQs
Q1: Why is my chimney smoking even after it was cleaned?
Because cleaning only removes Stage 1 creosote. Issues like damper problems, unvacuumed smoke shelves, Stage 2/3 creosote, negative pressure, or wind downdrafts can still block draft.
Q2: Can Metro Chimney PDX fix a smoking fireplace?
Yes. We diagnose all possible causes not just creosote and provide the correct long-term fix, including smoke shelf cleaning, draft correction, and safe creosote conversion.
Q3: Does Portland’s weather cause fireplaces to smoke?
Weather doesn’t create creosote but local wind patterns and pressure changes can affect draft temporarily. These are fixable issues.
Q4: Do you serve areas outside Lake Oswego?
Yes West Linn, Tigard, Tualatin, Beaverton, Sherwood, Happy Valley, Cedar Hills, and surrounding Portland metro cities including Clackamas, Oregon City, Milwaukie, Canby, Woodburn, Oak Hills, Forest Grove, Donald, Newberg, King City, Barlow, Aurora, Hazelwood, Fairview, Rockwood, Troutdale, Springdale, Sellwood, Moreland, Damascus, and Carver.