Okay, so we understand we have to ventilate our attic spaces, what exactly does that mean to the average layperson?
My apologies to any of my environmental consultant or building science expert friends who might saunter in here. This basic primer is geared more to helping the property owners who don’t understand the basic principles. Keep tuned though, as we’ll move onto some very interesting concepts regarding attics and ventilation concepts and huge energy savings. Well, first off, some of the components that you might see or need to understand would be:
* Soffit vents
* Ridge vents
* Gable vents
* Turbine vents – passive
* Powered fans
Soffit vents are where your roof extends beyond your exterior walls. Not all buildings have this feature. Go outside and look up, you’ll see vinyl or aluminum siding panels anywhere from 6? to 12? or so. There should be perforations for every rafter bay or every foot or two. If you have soffits, but no perforations they can be modified easily. Keeping insulation in the attic from blocking airflow through soffits is addressed by using Styrofoam baffles.
Ridge vents are at the peak of your roof. The sheathing should have a gap 3? to 4? wide. This gap is covered with a breathable membrane or vented piece of aluminum or some other building material. The concept is air will enter the soffit vents and take the heat, moisture and any gases and take them out the ridge vent. This is considered passive ventilation. This is a principle we call the stack effect – think of how heat rises. Proper ventilation will reduce the heat in your attic space in the summer reducing your energy costs and extending the life of your sheathing and shingles. In winter, the lack of proper ventilation has the same ability to create mold growth and the need for mold remediation.
Gable vents are what you generally find on the sidewalls of your building. There is usually one on each side. The wind has to blow in the right direction for them to work well. It’s generally agreed that they are inadequate in performing as well as the combination of soffit and ridge vents.
Turbine vents are amazingly effective as they work off the slightest of breezes and use no energy other than what Mother Nature provides.
Powered fans are just what the name implies, they can be electric or solar which is obviously more energy efficient. Bathroom and dryer vents should never be vented into the attic, as this will create an ideal environment for mold growth. Exhausts should go through the roof to be vented to the outside.
Mold has everything it needs to grow in most buildings and when you add water vapor you complete the formula perfect for mold growth and then you’re looking at degradation of building materials, possible indoor air quality issues and the expense of mold remediation.
Craig Camel, Advanced Mold Diagnostics