Garage Door Child

Take A Closer Look
At Being Too Snug In A Garage

If you live in a colder climate, the issue of how much R-value your garage door has may seem like a big issue.

Take a closer look.

With some manufacturers hyping R-values, one key issue of safety is being ignored.  Proper ventilation in a garage is critical.  It can be a matter of life and death.

R-values may give you a sense of being snug and secure, but a different value should be applied to the garage.  A garage, especially one that houses anything potentially combustible, should not be insulated like a home.  If anything proper ventilation is among the most critical of items.

There has been a measurable trend of garage explosions throughout the U.S. in the past few years as combustible materials are used in increasingly sealed off garages.

A Time Bomb Waiting To Explode In The Garage?

Expert: R-Value or Home Safety?

Can R-value be too much of a good thing?

Insulating the garage and trying to seal off the flow of outside air seems like a logical thing for a homeowner to consider.  After all increasing the R-value of an insulated garage can only make it more snug.  In cold weather regions, this may seem especially appealing.

However, a snug garage can be a time bomb waiting to explode, according to some experts.

Ralph Rangel, a senior technical staff member of the International Code Council (ICC), says proper ventilation of the garage is very important.  He suggests that investing in a garage door or anything that seals up the garage is a “misapplied value. “

Antone Clarck inspecting explosion
The remains of a Utah garage and home are nothing but rubble, as illustrated in this May 2005 photo. An explosion in the garage of this particular home blew the garage doors off this structure into the neighbors yard. Experts warn about the dangers of sealing off the ventilation in the garage.

“If it’s going to be sealed, this can create some problems,” Rangel said of the garage. 

Based in Chicago, the ICC is a membership group dedicated to developing codes that create better building safety and fire prevention for commercial and residential buildings, including homes.

Other experts agree with Rangel.

Dr. Greg Linteris, of the National Institute for Standards and Technology, describes the garage as a tremendous ignition source.    He said how much a garage leaks air, would be a factor in how combustible a garage could be.

The ventilation of the garage appears to be gaining some momentum, as far as potential safety and fire standards.  The state of California’s mechanical code calls for ventilation requirements for any garage that has a fuel-burning appliance.  It is especially stringent for new home construction---which is described in the code as “unusually tight.”

All of which negates claims by some manufacturers in the residential garage door or window business, for example, that having a high R value, with thermal breaks, double seals, or high-insulated value windows etc. is a benefit for the homeowner.

Mike Martin at garage fire

Unusually tight too often translates into potential carbon monoxide danger. 

The U.S. Environmental Protection Agency lists a number of cautions, involving the garage, in handouts outlining the dangers of carbon monoxide.

The outline lists sources of carbon monoxide as gas water heaters, wood stoves, fireplaces, gas stoves, generators and other gasoline powered equipment, auto exhaust from attached garages and tobacco smoke.  It stresses that a key step to reducing carbon monoxide dangers is ventilation.  More details on the dangers involving carbon monoxide are available at

Michael Lavallee, chief building inspector for Daly City, California, said any enclosure made unusually tight---i.e. caulking, sealing the windows, and buying a garage door with a high R-value---requires venting.

Historically part of the venting requirement for the garage has been dealt with by homeowners putting a vent in the garage door, according to Lavallee.  He said anytime you put a fuel-burning appliance in a confined space with limited airflow, you create the potential for carbon monoxide. 

“The room needs to be ventilated,” Lavallee said.

Exploded Garage

The garage doors were blown off and a car destroyed in this Pullman, Washington explosion.

Andre Desjarlais, group leader for Building Envelope Research of Canada, said garages should only be insulated if they are part of a conditioned space.  He said there are no guidelines in place for insulating an unconditioned space.  In most cases, garages are unconditioned spaces.

There appears to be growing evidence to suggest the argument about over-insulating the garage is not merely a theory. 

Consider the following recent news reports:

---a garage explosion in Susanville, California is linked to a man trying to siphon gas from his wife’s vehicle.  The man generated enough static electricity to ignite those gas fumes in a sealed garage. 

---in Hamilton, Ohio a home was destroyed after an explosion sparked a fire.  A person working on a car in a detached garage started the blaze.

---in West Jordan, Utah in April of 2005, a garage explosion was felt four blocks away.  The blast was so strong that the garage doors were blown off into the neighbors yard, almost 100 feet away.  The house was left as mere rubble in a matter of 10 minutes, one neighbor claimed.

        ---in Decatur Alabama, a garage explosion leveled a  home and rattled windows more than two blocks away.  The family was away on vacation at the time of the blast. 

        ---a faulty gasoline fitting on a vehicle was blamed for a garage explosion in Pullman, Washington.   The blast blew the garage doors off the building.