Roofing ventilation is an important yet often overlooked feature of roofing systems. In today’s post, the local roofing contractors at Kroll Construction share a look at how roofing ventilation works and the problems that can be prevented with proper ventilation.
How Does Roof Ventilation Work?
Warm and humid air tends to move upwards and collect in the attic, which can cause various kinds of problems if not vented out. A basic roof ventilation system needs to have exhaust vents that will release heat and humidity from the attic and intake vents that will let cool and fresh air through. There are two types of attic ventilation systems that can be installed on sloped roofs:
Passive ventilation — Passive ventilation systems use the natural rising movement of heat to release warm and humid air through vents located at the roof’s ridges. This creates negative pressure in the attic that pulls fresh air located at the lowest point of the roof, typically at the soffits. Both sets of vents need to be proportionally-sized to ensure efficiency.
Mechanical ventilation — Some roofing systems may utilize powered exhaust fans to replace or support ridge vents. Large mechanical ventilation systems with onion-shaped tops are typically seen on commercial buildings.
The Effects of Improper Ventilation
Poor attic ventilation can lead to the following problems:
Damage to insulation — The materials used for attic insulation, such as cellulose, fiberglass blankets, and expanding foam, tend to form clumps when in contact with moisture. This renders the material ineffective, as well as forms gaps in the insulation layer.
Structural damage — Prolonged exposure to heat and moisture can cause warping on a roof’s structural components, which can lead to a crooked or sagging roof line.
Mold growth — A warm, humid and dark space is the perfect environment for unchecked mold growth. Mold spores that spread to indoor living areas can trigger allergies and respiratory problems.