Posted by Karen Duke on 8/31/2018 to Tech
As owner of a bicentennial era home myself, I can attest that equipment from 40 years ago regularly breaks or becomes unserviceable when repair parts can no longer be had. However, when a water heater dies you're probably just going to have a cold shower. But when a metal fireplace has deteriorated you may not know it until a dangerous house fire occurs.
These prefab fireplaces became popular in the 1970's as an inexpensive alternative to building a masonry fireplace. Of great concern is the fact that they're now approaching 30 to 40 years old and causing a tremendous number of house fires. While a masonry fireplace may last as long as the house stands, a prefab wood burning fireplace is considered within our industry to have a lifespan of 10 to 30 years.
Prefab decorative wood burning fireplaces are made of relatively light weight metal; precast "firebrick" style panels and air chambers are all that separate the fire from your framed walls. This photo shows a fireplace installation before sheetrock has been installed. Isn't it kind of scary that framed walls are actually that close to a wood fire? Many really are made like a cheap tin can and installed against the walls of your home. And there's a lot that can go wrong.
Even when installed correctly - meeting the manufacturer's minimum clearances to combustibles - they just were not designed for heavy duty use for decades. Unfortunately, time and age are beginning to show on these old fireplaces, and tragic house fires are now occurring on a regular basis.
PRIMARY SAFETY CONCERNS
*Improper Installation is far and away the most common cause of failure. If clearances to combustibles weren't closely followed, along with exact configurations of the metal chimney venting, the ignition temperature of the wood and sheetrock nearby the fireplace can be reduced over time, a process called "pyrolysis".
*Improper Use Keep in mind that a prefabricated wood fireplace is designed for occasional, recreational type fires. Don't overfire by building large, hot fires or use them for hours and hours on end to try and heat. By and large, these fireplaces are considered decorative appliances and are not designed to provide substantial heat.
*Field Modifications It is extremely inadvisable to install a wood stove (such as a wood burning insert) into a prefab fireplace. Use caution when attempting to install after-market glass doors, too, that may interfere with the fireplace's design to circulate and disperse heat properly. Never attempt a renovation project that covers louvers or air channels that were designed to help keep the fireplace properly cooled.
*Inadequate Maintenance It's imperative that you have your chimney checked annually and the chimney swept when needed. One of the most important aspects of the inspection is the chimney termination on your roof. The flashing surrounding the chimney pipe easily becomes
deteriorated over the years, contributing to water damage, rain leaks and rotting wood. Deteriorated flashing can also allow birds and animals to enter the chimney chase (the framed "wooden" chimney area) where varmints often build flammable nests adjacent to the pipe.
If you're advised of a safety or performance issue, DO NOT use your fireplace. It's time to investigate replacement or alteration.
REPLACEMENT OPTIONS Keep in mind that the fireplace must be removed from either the front facing wall, or from the rear. Removal from the rear is usually the easiest method, especially if the framed chase has been covered by siding. Remove the siding and underlayment to gain access to the inside of the chase. The chimney is normally removed from the top and sometimes the chase is large enough to actually get inside of in order to assist in unscrewing and disconnecting the chimney sections. Removal from the front of the fireplace opening commonly involves removal of the facing material (slate, marble, tile, etc) and the mantel, resulting in a bigger mess and more work overall.
When it comes time to choosing a new model to install, consider the options available to you. Commonly the original model was a "builder grade" appliance, an inexpensive model with minimal features.
New, high-efficiency wood burning prefabs are available that are manufactured with quality metal, tightly fitting doors and energy efficient combustion designs that provide burn times and heat output comparable to a woodstove. If you still enjoy wood fires then why not consider a high-efficiency model that can help provide substantial heat when needed? This classification of wood burning fireplaces also uses upgraded chimney systems meant to withstand higher temperatures.
Gas Fireplaces provide the beauty of real flames without the work and mess associated with burning firewood. Like wood burning fireplaces, gas models are classified as "decorative" or "heater rated". Heater rated models have a glass window instead of an open fire, protecting against contact with open flame. Most models also work during power outages, providing excellent backup emergency heat if you've chosen a heater rated fireplace. Unlike woodburning fireplaces where the type, condition or amount of wood greatly affects heat output, gas fireplaces are designed to withstand a maximum constant heat production so overfiring is never a concern. Heater rated gas fireplaces use the gas more efficiently and tranfer that heat to your living space, providing substantial heat when desired. Better models also offer thermostat control that modulate the flame to adjust the heat output so you're never too warm. Direct vent models, which use outdoor air for combustion, provide versatile installation and venting options where a woodburner couldn't be used.
ALTERATION OPTIONS The expense and labor involved in a prefab fireplace replacement may lead you to consider a conversion or alteration of your fireplace. CAUTION: ABSOLUTELY DO NOT PUT GAS LOGS into a damaged or deteriorated woodburning fireplace. Vented gas logs require the fireplace and chimney to be suitable for use with wood; if it's not safe to burn wood, it's NOT SAFE to use with gas logs, either! Ventless (vent-free, unvented) gas logs are far worse; they're designed to allow you to close the damper, keeping the heat produced concentrated in the fireplace where they're more likely to cause a problem including pyrolysis of the adjacent wood framing within the wall.
A GAS INSERT is essentially a stove that inserts into your fireplace and may be a practical option to tearing out the fireplace that's already there. As some gas inserts carry a dual listing as either an insert or a complete fireplace system, inserting it into a metal fireplace should not cause fire safety concerns. Again, you'll have the convenience of burning gas and it's comparatively inexpensive versus replacement of the fireplace. They heat great, have a great flame and you'll never have to tote wood again!
An ELECTRIC INSERT is a very inexpensive option. An electric fireplace is uniquely capable of offering you flames with no heat so you can have a romantic fire in the summer, or use with the heater when the weather turns chilly. This at least provides you the ambience of a "fire" with no need to tear anything out, and is an option many of our customers have chosen in recent years.