Change your decor in complete safety!

The installation of a fireplace mantel made of combustible materials (such as wood, gypsum, etc.) requires certain fire-safety standards regarding the minimum distances to be respected between materials around a prefabricated fireplace or the hearth of a masonry fireplace.

These distances DO NOT APPLY TO OUR MANTLES, STONE WALLS AND WALL SHELFS, which are all made from our fabulous MICRO-ROCK® product!

MICRO-ROCK® fireproof technology is the basis for all our products. Discover it here.

Zero-clearance fireplace decoration: not to be taken lightly!

(Exergue) Minimum distances must be respected when installing a chimney mantel.

In the 90s, fireplace manufacturers developed and perfected a technology commonly referred to as "zero-clearance", whereby the fireplace can be placed directly against normal building materials such as wood, plywood, gypsum board and decorative wood panels. These "zero-clearance" fireplaces, with their perfectly safe insulated casing and combustion chamber, are in fact safe from any risk of fire in the very structure of the wall in which they are built, as long as they are installed to the prescribed standards.

A clarification is in order!

So far, so good! But where things get dangerously complicated is when it's time to dress up the fireplace, even though popular belief has it that the same rules apply to mantels. But that's not the case at all!

The Underwriters' Laboratories of Canada installation, use and safety guide clearly states that the term "zero-clearance fireplace" - implying that there is no need to leave a clear space between the fireplace and surrounding combustible materials - can be misleading to consumers.

Minimum clearance zones

In fact, no matter what anyone says or hears, it's essential to respect certain minimum clearance zones from combustible materials at right angles to the fireplace, regardless of the design or build quality of the fireplace model. We're referring here, of course, to the mantel, the decorative part that projects above the fireplace, but also to the hearth extension (floor in front), the side wall and the ceiling.

As a rule, the installation manuals that accompany the purchase of a fireplace mention these requirements, although they are not always given the importance they deserve. What's more, the diagrams illustrating the distances to be respected are often open to interpretation.

While these clearance zones may vary considerably from one model to another, on average there should be a clearance of about 50 inches between the bottom of the fireplace and the first wooden moulding fixed above the fireplace; the hearth extension should be made of non-combustible material over a distance covering a depth of 16 to 24 inches in front of the fireplace and a width of 42 to 72 inches; a space of at least 12 to 18 inches must separate an angled wall from the corner closest to the fireplace; finally, the ceiling must be at least 84 inches (7 feet) from the bottom of the fireplace, with the exception of a few zero-clearance units on top.

70% of households are non-compliant

Of all these restrictions, the one concerning mantels is by far the most flouted. Easy to understand! Few homeowners will call in experts to install a mantel, an accessory that's more a matter of decoration than the actual framing of the fireplace.

A lack of knowledge coupled with the confusion sown by the notion of zero-clearance fireplaces.

A lack of knowledge coupled with the confusion sown by the notion of zero-clearance fireplaces leads do-it-yourselfers down a very wrong path. In the opinion of Mr. Jean-Paul Jodoin, an expert who has been working in the fireplace decorating industry for 15 years, 70% of fireplaces transgress the basic safety standards laid down by the CMHC and the Building Code.

Perfectly contouring a fireplace obviously adds a more aesthetic look, which is nothing to sneeze at; especially since a fireplace can look a little "lost" under a mantle that respects the permissible limits.

This is what prompted Mr. Jodoin, president of Fini-Plus, to develop a fireproof product marketed under the name Micro-Rock in the mid-90s. In fact, it's a sure-fire way to legally evade these restrictive guidelines without endangering the lives of those around you.


In Quebec, the certification of heating appliances is carried out by Les Services d'essai Intertech. Formerly known as Warnock Hersey, this laboratory certifies compliance with the safety standards set by the Standards Council of Canada.

Whether or not they are zero-clearance fireplaces, each model must be tested, certified and installed in accordance with the prescribed standards, and the combustible mantel is no exception.

"The certification given by the laboratory is proof that this installation is safe, which doesn't mean that another one isn't", says Claude Pelland, Regional Director of Physical Testing and Certification. Except that no one can ensure or guarantee its safety.

Failure to do so could result in overheating and pyrolysis of the mantle. "Generally speaking, it will degum; no varnish or paint will hold," says Pelland. In the worst case, it could char and start a fire.


To date, a fire caused by failure to respect minimum clearance zones between the combustible mantel and the fireplace would not be a cause for claim rejection, however, assures Raymond Medza, General Manager of the Insurance Bureau of Canada (IBC). "Unless there is criminal intent, loss or damage caused by fire is covered, regardless of whether there was a procedural defect in the installation," says Medza.

Par contre, il n’est pas exclu que des recours soient entrepris contre les installateurs s’il s’agit de professionnels à leur compte ou d’entreprises ayant pignon sur rue.

“"The most frequent cases we have to deal with are fires caused by auxiliary heating appliances, i.e. slow-burning stoves"., notes Mr. Medza, pointing out that most fireplaces play a more ambient role. "Fireplaces give off heat, but you can't rely on them to keep your home warm"., soutient-il.

Yet new technology makes prefabricated "zero-clearance" fireplaces just as efficient as slow-burning stoves, says Jean-Paul Jodoin, our fireplace facing expert. As proof, he points to some fireplaces that, after just one hour's use, heat to over 1,200 degrees F. at the hot air outlet. The installation guides distributed by some municipal fire departments put a lot of emphasis on auxiliary heaters and not necessarily on fireplaces," concludes IBC's General Manager.

If you're not sure about the standard of your home, contact us!

If you can't find information for your fireplace model with your manufacturer or on the Internet, contact us at or at (514) 592-9537, outside: 1-888-592-9537. We'll be happy to help you.

Our fire-resistant MICRO-ROCK® technology is the basis for all our products. Discover it here.

A BIG thank you to journalist Stéphane St-Amour, for this most educational article!