A newcomer to my suburban neighborhood asked me why the peaks of all the houses on my street stick up. Since he is a fellow firefighter, I assumed he knew what I was talking about when I quipped, “ridge vents.” When I questioned other firefighters, I realized ridge-vent knowledge is not as common as I thought. A thorough explanation of the subject elicited a yawn from the newcomer, so I put the topic to bed.
One month later, I was at work in Buffalo when one of my daughters called to tell me a column of thick black smoke was rising a few streets away from our house. I said it was probably a car fire and asked if the local fire department had been notified. She said she could hear sirens and the column was becoming even bigger and blacker. I told her it had probably caught the garage, too.
When I got off work several hours later, I went by the scene of the “car fire.” I could see aerial platforms rising above the neighborhood from a block away.
It turns out that a car had started to burn in an integral garage of a large two-story, wood-frame home. The flames quickly spread to the vented soffit material above the opened garage door and then traveled up the Styrofoam channels to the ridge vent. There could not be a better example of a fire triangle, as the fire quickly roared out of control.
The house and its contents were a total loss. The burned out shell was later demolished and a new house was built in its place (see bottom photo, this page). Building codes dictate that a separation must exist between the garage and living space. The vented soffit, Styrofoam channel and ridge vent do not violate the code because they do not come into contact with the living space.
Ridge Vents Defined
So what are ridge vents? They are actually part of a total roof-venting system designed to provide air circulation in attics, thereby helping to keep homes cooler in summer, reduce humidity and increase the life of roofing materials.
Although the use of ridge vents has grown during the past 10-15 years, it is not a new idea; for example, one article found in a 1935 issue of Popular Mechanics magazine was titled “Homes Cooled By Heat Valve On Ridge Of Roof.”
Early ridge vents appear strikingly similar to modern-day ridge vents; the early design draws in outside air at the base of the building and uses convection currents to push out heated air through the ridge-a good thing on a hot day, and a great thing if your house is on fire.
The main components of the modern air-circulating system include soffit or eave intakes (vents), a pathway for the air to travel to the ridge and the ridge vent. The vents at the eaves are usually perforated sections of aluminum or vinyl siding designed specifically for soffits.
After the air moves through the soffit material, it must travel through a channel to the ridge. In an unfinished attic space, the channel between the roof rafters would be open and air could easily move to the ridge. In a finished or partially finished area with insulation, Styrofoam channels are usually utilized to allow air to pass in between the roof sheathing and the insulation.
Depending on manufacturer recommendations, a two-inch (or more) section of sheathing is removed on both sides of the ridge. This section could run the length of the ridge. If the manufacturer called for an opening at the ridge of two inches on each side, and that ridge was 30 feet long, the opening would measure 10 square feet-a good initial size opening for ventilation. A 4′ x 4′ hole is 16 square feet.
There are several different styles of ridge vents. One example features a membrane material that comes in a roll, which is nailed to the ridge with roofing nails and then capped off with shingles nailed through mesh into the roof sheathing. Another type is made of hard plastic that comes in approximately 4′ sections. This one is also nailed down to the ridge and then covered with a top cap of shingles.
If you encounter the metal type of ridge vent that lacks a shingled cap on its top, you will find you can easily remove it. This vent is attached with roofing nails that either pull out when you pry on the vent or simply pop through the material. (There may be other types and installations on the market, but these descriptions should provide some general information about most installations.)
Venting the Vents
Almost all ridge vents you will encounter are easier to remove than chopping through the roof. I recently worked a fire in an older home that had just been remodeled. The remodeling included a new roof. The fire had taken a good hold of most of the house, and I was asked to vent the roof. So I went to the peak and straddled it in preparation to start chopping. I felt tremendous heat on my inner thighs and realized the peak I was straddling had a ridge vent out of which superheated air was oozing.
This vent was the rolled-mesh type. With the pick end of my axe, I pulled on the shingle cap and the rolled ridge vent, and big chunks of them began to come off. Dark black smoke began to chug out of the 4-inch-wide slot in the peak for the ridge vent. I vented the roof without ever having to chop through wood. Was it enough of an opening? It was at first. There was a hole in the highest point over the fire when crews on the inside needed it most.
What’s the Verdict?
So are ridge vents a good thing or a bad thing? Well, it depends. If they help spread the fire, that’s bad; if they help ventilate, that’s good.
If a house features vented soffit material outside a window and fire is blowing out that window and traveling up the channels to the ridge vent, that’s bad. If you have a 40-foot-long roof equipped with a ridge vent, and you must open the roof quickly, you will create a pretty good-size hole just by pulling off the ridge vent. That’s good. As more ridge vents show up in our buildings, we’ll just have to take the good with the bad.
Peter F. Kertzie is a 17-year veteran of the Buffalo (N.Y.) Fire Department, currently serving as captain of Truck 14. He is a New York State-certified Municipal Fire Training Officer and holds a Bachelor’s degree in business and an Associate’s degree in fire-protection technology.
