Many people have never taken the time to look carefully at a roof and to think about how it works.
It is common to think of a roof simply as a wall on top of your house.
Because it gets more exposure to sun and rain, and is less visible from the street, we cover this “top wall” with shingles to provide enduring protection from the elements.
But a roof is far more complicated than that. To understand how it truly works to keep you safe and dry, it is better to think of the roof as a living organism. And one of the most important thing a living organism does is breathe.
What are all those open spaces?
Vents, soffits, and air, oh my!
An insulated attic must breathe in order to stay healthy and dry. That is, there must be air flowing in and out of the attic, and often the most efficient way to achieve this is by simply providing vents for air to flow through.
This is accomplished through several different tools:
Soffit vents: soffit vents can look a bit like air conditioning or heating register covers. They are visible in the soffits where the roof sticks out over the edge of the walls of your house. They are simply opened spaces, covered with mesh to prevent bats and other pests from coming in with the air.
Roof vents: These small, shallow metal vents are painted to match or complement your roof tile or shingle. They have an opening that faces downward to prevent rain from getting in. These partner with soffit vents to allow for upflow when the attic air becomes heated. This air vents out and is replaced by air that comes in at the soffits.
Fans: in some larger or problematic insulated attics, fans are installed to make the system more efficient. They can draw air in from outside and force it more quickly out other vents or openings.
Temperature-triggered fans: If overheating is a problem, a vent fan might be attached to a thermometer that triggers the fan at a given temperature. This temperature can be set manually.
Many builders in climates that experience temperature extremes use a hybrid approach. Passive airflow is available through vents, but a temperature gauge will be attached to a fan, and it will come on when the attic gets too hot.
By “breathing” in this way, your insulated attic helps protect your home while staying dry and in good condition.
