Roof Ventilation Problems We Often See in Edmonton
We Fix Them Every Day Before They Turn Into Costly Repairs!
Edmonton’s Winter: Why Ventilation Problems Get Worse
Edmonton roofs face heavy snow, extreme cold, freeze-thaw cycles, and sudden temperature swings. When attic airflow is restricted, warm humid air becomes trapped. This leads to frost buildup, wet insulation, mold growth, and leaks during quick temperature swings.
Ventilation mistakes we see every single day in Edmonton homes.
1. Blocked Soffit Vents
The most common issue we find. Insulation is often pushed tight against the soffits, completely blocking fresh air intake.
Symptoms:
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Frost on nails
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Wet or compacted insulation
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Stains on roof trusses
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Rusty nails
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Ice dams forming at roof edges
How we fix it:
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Install proper attic baffles
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Clear and reopen soffit vents
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Restore continuous intake airflow
2. Not Enough Roof Vents
Many Edmonton homes are under-vented with too little exhaust ventilation.
Symptoms:
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Heavy frost on attic wood
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Musty or damp smell
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Moisture staining
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Premature shingle aging
How we fix it:
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Add additional static roof vents or install a ridge vent
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Balance attic intake and exhaust ventilation
3. Mixing Vent Types
Example: ridge vents combined with box vents or turbines. These systems fight each other and short-circuit airflow.
Symptoms:
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Cold spots in the attic
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Moisture problems despite many vents
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Uneven airflow
How we fix it:
Use one ventilation system only:
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Ridge vent OR
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Static vents OR
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Turbines
Never mix systems.
4. Bathroom Fans Venting Into the Attic
This is extremely common in Edmonton homes and a major source of moisture.
Symptoms:
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Thick frost on attic plywood
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Dripping around bathroom exhaust fans
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Wet or sagging flex pipe
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Mold near fan exhaust areas
How we fix it:
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Vent bathroom fans through the roof, not into the attic
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Install insulated ducting
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Properly seal roof caps
5. Incorrect Plumbing Flashings
Wrong-size boots or cracked seals allow warm air and moisture into the attic.
Symptoms:
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Frost buildup around pipes
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Moisture near flashing boots
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Water dripping during warm spells
How we fix it:
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Replace flashings with correct 4-inch ABS boots
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Ensure airtight seals
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Add insulation collars where required
6. Poor Insulation Causing Heat Loss
Even good ventilation fails if excessive heat escapes into the attic.
Symptoms:
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Melted snow patches on the roof
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Ice dams
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Warm attic temperatures
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Condensation on roof sheathing
How we fix it:
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Increase attic insulation
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Seal attic bypasses
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Maintain airflow with proper baffles
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Minimum recommended insulation: R-50
7. Incorrect Attic Vent Installation
Common mistakes we see:
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Vent openings cut too small
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Ventilators misaligned due to improper installation
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Ridge boards or blocking not removed
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Shingles blocking airflow
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Vents installed on low-slope areas where they cannot seal properly
How we fix it:
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Re-cut vent openings to manufacturer specifications
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Remove blockages
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Ensure balanced soffit intake
Why These Problems Matter
Ignoring ventilation issues can lead to:
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Structural moisture damage
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Mold growth
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Higher heating costs
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Ice dams
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Premature roof replacement
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Spring leaks during chinooks
Almost all attic condensation problems are caused by poor airflow, not Alberta weather.
How to Protect Your Edmonton Home
A proper attic system includes:
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Clear soffit intake
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Balanced exhaust ventilation
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Correct bathroom fan venting
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Proper insulation (minimum R-50)
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No mixed vent systems
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Correct flashing around roof penetrations
If you’re seeing frost, dripping, or mold, it’s fixable but it won’t fix itself.
At PJ Roofing, we quickly diagnose and fix ventilation and attic condensation problems every single day.
If you’re dealing with frost, moisture, or attic condensation:
