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Tuesday, May 08, 2012

The Importance of a Properly Vented Roof

There are many things to consider when replacing your roof. Some are simple such as what style or color and others are more complex such as, what type of roofing system should be installed on my roof? Or, what are the requirements in order to qualify for the manufacturer’s warranty?  Today I’d like to talk about the importance of a properly ventilated attic space.

 There are a few important reasons to properly ventilate your attic space and here are just a couple.

 1.    Heat in the attic during the summer

 One of the main reasons for proper attic ventilation as part of your roofing system is to keep air flowing under the roof deck in the attic space to cool the attic and remove warm air from it. This helps to prevent shingles from baking on the roof deck and pre-maturely aging them. Most shingle manufacturers will not warranty the shingles unless the attic is properly vented with some form of attic vents which I’ll discuss later.

 2.    Condensation in the attic space during the winter

Have you ever looked inside your attic space in the winter and seen a beautiful layer of crystal white frost on the underside of your roof deck? It looks really neat and sparkly. Although it may look cool (no pun intended) it’s a sure sign of an improperly vented attic space. What’s happening is that some heat from the home will make its way into the attic space, sometimes even with proper insulation and vapor barrier. This warm moist air is condensing on the cold underside of the roof deck. The frost will continue to grow until it either melts or is able to evaporate and ventilate out of the attic space with air flow. This is one of the best ways to make it rain in your house either in January when you crank up the heat or on a nice warm spring day when the sun warms the roof deck and your lights and door headers start to drip. Talk about being confused! It’s raining in the house but not outside?  Trust me, those have been some of the most interesting telephone conversations I’ve had with soon to be customers. 

 All kidding aside, the basic idea is that in order to properly ventilate an attic space there needs to be proper air intake as well as proper air outflow or exhaust. A 50/50 balance between intake and exhaust is ideal. There are several types of each of these ventilators but let’s keep it simple. A typical home will have an overhang or soffit which is usually where the intake vents are located. Either air intake grills at approximately every 8’ to 10’ or it will have continuous vented soffit panels. The most common exhaust vents we see in Manitoba are static exhaust vents. Roof vents near the peak of the roof. Studies show that the best ventilation for a roof is called ridge venting. Essentially this is a strip vent fastened at the peak of the slopes with a properly sized strip cut out of the roof decking to allow proper air flow. One of the most common types used today is shingle over ridge venting. They work well and look great. Click on this link to view a great video on Lomanco’s LOR 30.  We like it because of its superior baffle system which prevents snow from blowing in during a storm and does a great job of venting.

If you’re having problems with attic venting or need your roof replaced, call us at 233-4664. We’d be happy to ensure your roof is properly vented.  Until next time, remember, “We look forward to serving you!”


Take care,

Lansard Bros Roofing



Posted by Lansard Bros. at 4:32 PM 4 Comments