Condensation in Calgary

Condensation in the attic of your Calgary home, commonly referred to as “attic rain”, is often mistaken for a leaky roof. Over the years our homes have become increasingly energy efficient and well insulated. The result is an airtight house that is smothered and no longer “breathes” on its own. This, along with a number of other factors, can lead to condensation in your home. Proper attic ventilation can often help the home breath and clear up a condensation problem.

Our Exterior Experts have years of experience inspecting attics in Calgary homes and providing solutions.  It’s not an easy (or clean) job but we are happy to offer free inspections to ensure your home has balanced ventilation and adequate insulation.  The attic can tell you a lot about your home and shouldn’t be ignored.

What is Attic Rain?

Condensation in the attic is a direct result of warm, humid air finding its way into the attic and then freezing in our extremely cold weather. The longer the cold snap, the more opportunity the moisture has to accumulate into frost. When the weather starts to warm up again, the frost melts and homeowners may start to notice moisture leaking into their home. This has recently become known as “Attic Rain”, a relatively new term in the industry.

What are the Warning Signs?

Condensation in the home is usually noticed first as water droplets forming on windows and skylights. It is natural to assume the cause of the condensation is the windows, but they are not always to blame. The windows may be an initial indicator of excess humidity in cold weather.

Conquering the Myth – Windows Do Not Cause Condensation

Ice damming on the roof may also be a sign of attic condensation and can cause an additional range of problems.

See our Ice Damming page for more information.Ice damming on the roof may also be a sign of attic condensation and can cause an additional range of problems.


Noticing water stains or dampness?

The most common area to first notice a “leak” inside your home is around bathroom fans, lighting fixtures and/or windows.  Homeowners in Calgary often report finding water in their lighting fixtures that are on the ceiling below the attic.

The most common areas on the exterior of the home to first notice a “leak” is through the soffits. Also, a sticky, brownish resin down the exterior walls of the house may be an indication of condensation.

condensation sign image

What are The Usual Suspects?

Commonly they are a combination of these factors:

  • Bathroom fans, dryer vents, kitchen hood fans, or other exhaust fans venting into the attic or not connected properly
  • Inadequate insulation and/or ventilation
  • Blocked soffit intake vents (commonly occurs after adding or upgrading attic insulation)
  • Excessive humidity in the home
  • Recessed lights not properly insulated
  • Openings or holes in the vapor barrier
  • Leaving the attic hatch open
  • Long periods of cold weather
  • The list of possible causes goes on…

Potential damage?

  • Insulation can become compromised and ineffective
  • Water damage to the ceiling, walls and windows
  • Peeling or blistering paint
  • Warping or rotting wood
  • Damage or delaminating roof decking
  • Ice lifting and pushing in behind the shingle
  • Mold could start to form if left neglected

Best Course of Action?

  • Finding the main sources of the excess humidity
  • Ensuring your humidistat is properly set in relation to the outdoor temperature
  • Ensuring adequate roof intake and exhaust vents are installed and working properly with no blockages.  In the winter, large amounts of snow can block these vents and cause attic issues.
  • Checking the attic insulation for proper install and function.

CAUTION! – Just adding additional insulation may not help and can potentially make the problem worse.

Learn how Hubbard Roofing can help you solve your attic rain problems with top quality, professionally installed ventilation systems

For further information or assistance Contact Us to find out how we can help.

What is Ice Damming?

In the winter months when snow blankets the roof, ice damming can occur when the heat from the attic and/or roof deck starts to melt the first layer of snow. The melting snow will run down the roof until it reaches the cooler overhang of the roof where it will freeze again, creating a thick accumulation of ice along the bottom edge of the roof. The ice builds up, blocking the gutters and causing water to collect behind the dam while the cycle of thawing and freezing continues. This can lead to a multitude of problems to both the exterior and interior of the home.

ice dam diagram

What Causes Roofline Ice Dams?

  • Insufficient or defective attic insulation – As heat is transferred through the frame it warms the roof deck and melts the snow.
  • Ventilation – Attic intake and exhaust vents need to be functioning properly to remove warm, moist air.
  • Household air leakage – See The Usual Suspects for a list of factors that can contribute to a warm roof deck.
  • Snow – Snow is an excellent insulator and 10 inches of snow is roughly equal to a 6-inch layer of fiberglass insulation. If there is enough snow on the roof it can insulate the attic and warm the air inside, causing the snow to melt.
  • Low pitch roofs – These are particularly susceptible to ice damming. The lower the slope, the easier it is for the ice and water to anchor.

What is the Potential Damage?

ice damming image

The collection of water behind the ice dam can back up under the shingles and underlayment, causing a leak into the attic or living area. If undetected or neglected, this can result in water damage to roof decking, wood studs, insulation, drywall, paint and may even attribute to mold growth in the home.

Large amounts of ice and icicles can damage skylights, gutters, soffits, fascia, windows, siding and stucco.

In some cases, ice and water can build its way back up the roof 5 – 10 feet, causing lifting of the shingles and underlayment. Roofing systems are designed to shed water down the roof, not up, and underlayment is overlapped accordingly.


Solutions & Preventions

Your attic temperature should be relative to the outside temperature. Hot in the summer and cold in the winter. If this is not the case, your home may be at risk for ice damming.

If you are experiencing reoccurring damming, a water-tight membrane is a great solution. There are a number of underlayment options on the market to seal the roof deck and prevent water from penetrating the sheathing, such as Ice & Water Shield.

If ice damming persists and you’ve exhausted all other options, heat tape for the bottom edge of the roof may offer additional protection.

See the Best Course of Action for additional attic related solutions.