The Dangers of Having Excessive Attic Heat
September 23, 2016
It sounds somewhat counter-intuitive, but many homes, particularly those that are older than 20 years, suffer from excessive heat in the attic. In most cases, it's an unseen problem, but could very well lead to other issues, both in summer and in winter. In summer, excessive attic heat can overheat the underside of the roof and compromises the shingles. In winter, excessive attic heat can allow for moist air to build up, and further cause ice to build up across the entire roof area.
Interestingly, excessive attic heat can also cause some types of attic insulation to compact. This will naturally reduce insulating effectiveness and affect R-Values. As it is, there are a few reasons for attic heat to build up. Firstly, if attic insulation is inadequate, heat from inside the house will rise into the attic cavity. Secondly, when attic ventilation is either insufficient or non-existent, there's no opportunity for air flow or air exchange to ensure balanced ventilation for the space.
Another dynamic that many homeowners overlook in the attic is air sealing. And while sealing and ventilation may seem to be incongruent, they work together in collaboration, particularly in a space like the attic. Upgrading attic insulation is an excellent first step in confronting attic heat. It creates an excellent "line of defense" by preventing heat from migrating into the attic. As for the ventilation, this too requires either upgrading or retrofitting to properly address attic heat.
Excessive attic heat evidences itself very clearly in winter. In fact, as the winter approaches, many homeowners flashback on the previous winter when they witnessed "ice damming". And for the most part, this is not a roof problem or an eaves problem. It's basically an insulation problem. When attic insulation is old or compromised, the attic fills with warm air from inside the house, the roof snow is caused to melt, and the re-freezing of snow will cause unwanted "ice damming".
In short, indoor heat (during winter) should not be migrating into the attic, and good insulation will prevent this. As well, the attic cavity must be properly sealed - this will avert air movement and moisture collection, both of which are undesirable in any cavity. Finally, when the attic space is well ventilated, the "system" as a whole is properly balanced, allowing for installed insulation to perform at peak, and provide all of the advertised properties that a homeowner expects.
For professional insulation contractors, attic insulation is about designing a "system". Here, Spray Foam Insulation has proven itself as ideal for the attic or roof cavity. SFI is a product that does it all with one application - it completely seals the attic space; it inhibits any air movement; and it prevents moisture and vapour from collecting. Beyond this, the installed R-Value exceeds other comparable installations. All things considered, SFI addresses excessive attic heat with success.
Nothing on the market quite compares with Spray Foam Insulation. And with excessive heat in the attic, no other installation can compare with the long-term outcomes.