Why vents matter

Did you know wind-blown embers can enter attics and crawl spaces through vents, increasing the risk of fire to your home? Vents in attics and crawl spaces Attic and crawl space vents serve important functions. They provide ventilation to remove unwanted moisture from these typically unoccupied spaces and provide oxygen for gas appliances such as hot water heaters and furnaces. However, wind-blown embers are the principal cause of building ignition and can readily enter these spaces, which are often hot and dry. Providing air for ventilation, while also keeping out embers, can present a dilemma. Dry materials are more easily ignited by embers, so limiting the entry of embers into attic spaces is critical. Adding to the problem are the combustible materials we tend to store in these spaces (e.g., cardboard boxes, old clothes and other combustible materials) because embers accumulate against them and they can be easily ignited. Use mesh screening to reduce ember entry into vents Most vents consist of quarter-inch mesh screening. However, research shows embers can pass through quarter-inch mesh and ignite combustible materials, particularly smaller materials such as saw dust. Installing 1/8-inch mesh screening is suggested in wildfire-prone areas, as it effectively minimizes the entry of embers. It's important to note that 1/8-inch screening only minimizes the size and number of embers and does not eliminate them entirely, making it very important to reduce what's stored in the attic and crawl space. You can buy rolls of 1/8-inch mesh screening at your local hardware store and simply staple them over your existing vents. More sophisticated fire-resistant vents, such as Vulcan Ventrs, are also available to replace your existing vents. 3 tips for upgrading your home's vents For attic vents under the eaves, opt for a soffitted eave design. Research demonstrates that vents that are perpendicular to the wind are more vulnerable to wind-blown embers. By having vents that are parallel to the wind flow, as those in a soffitted eave design. For outlet vents, opt for a ridge that is rated to resist wind-driven rain. These vents have an external baffle at the vent inlet. These vents have been approved for use by the California Office of the State Fire Marshal. Turbine vents also help keep embers out, but you should attach a piece of 1/8-inch mesh to the bottom of the roof sheathing at the opening for the vent. Upgrading your home's vents are one of the most important things you can do to protect it from wildfire. For more information, contact your Firewise Resident Leader or Dory Cox at 530-401-1750.