roof condensation damaged roof deck frost rot

Condensation in the Attic Causing “Leaks”

Is your roof leaking? You may see the telltale signs of water damage: water stains and drips coming from the ceiling. Maybe a moldy smell. But there may not actually be a leak. If the weather has just gone from -35 to +5 degrees in less than 24 hours, you may be experiencing roof problems caused by condensation.

Why is there Condensation in My Attic?

When air is very cold, like it gets in Edmonton every year, it can’t hold much moisture. So when warm air escapes from your house (and it will–there is always going to be some heat loss to the attic), the moisture quickly separates from the air and attaches itself to the attic.

Every house has places where warm, moist air can escape into the attic: bathroom vents, kitchen exhaust vents, chimney flues… Vents in general are big sources of attic heat and moisture.

Once warm air hits the attic, but before it vents outside, your cold attic air separates out moisture, which then turns into frost. The frost will build up on the underside of your roof deck, on nails, and even in the insulation!

The problems start when the temperature suddenly heats up and all that frost melts. That’s when you’ll start seeing signs that make you think your roof is leaking:

  • Water stains
  • Discolouration of ceiling/walls
  • Rust on the nails in your attic
  • Drip marks on the attic floor
  • Buckled or damaged roof sheathing
  • Moist insulation

But your roof may not have sprung a leak …yet. You could be experiencing roof condensation problems.

How Do I Fix Roof Condensation Problems?

Condensation problems can happen in any type of roof, residential to commercial. There are two main reasons for condensation problems:

Improper sealing or insulation of the vents that let warm, wet air into the attic.

When you’re dealing with roof condensation, you have to make sure that your vents are all properly sealed and that no warm air escapes through cracks or gaps.

Bathroom and kitchen exhaust vents need to be well insulated so that the hot air stays hot until it is all the way outside.

In general, your attic needs a certain amount of insulation. If there isn’t enough, it could make condensation problems worse. Add more insulation if your roof needs it.

Tip: Check to see if there are any major reasons for excess heat in the attic. @InspectorPeter found a broken furnace pipe!

Improper ventilation of warm air from the attic.

If all your vents are sealed up and no excessive heat or moisture is getting into your attic, that’s a great first step. The next step is making sure there is adequate airflow to allow hot air and moisture to escape.

There is always going to be some frost buildup on the underside of your roof in the winter, and good ventilation will ensure that the moisture gets out.

Check to make sure that you have intake and exhaust vents and that there are enough of them. Proper roof ventilation isn’t always as simple as it sounds, but a good roofer will be able to assess your roof’s ventilation situation and recommend any changes that need to be made.

Want to know more about the fascinating topic of roof ventilation? Read Roof Ventilation: What’s it all About?

Is your roof “leaking”? Do you think it might be condensation? If you’ve had a major weather change recently, that could be what’s causing water damage.

Another common winter roof problem is Ice Damming along the eaves of your roof.

Don’t Ignore Roof Condensation Problems!

You might be tempted to ignore a winter roof problem, hoping that once the weather improves, things will sort themselves out. But condensation makes great conditions for mold and rot, and in the worst case scenario, you could end up with roof holes or collapse.

For any of your roof needs, including attic insulation and ventilation to prevent condensation problems, the experts at Crest Roofing are just a phone call away! Give us a call at 587-400-7523 or send us a message.

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