Building Code for Fireplace Mantel Placement

May 15, 2013
Tom Cox
General Manager

We often get questions about how near the firebox a fireplace mantel can be placed safely. I had to research this question myself when we built our house so I wrote this article. We will discuss the following topics:

I include some links to building code sites below so you may want to bookmark or save this article for future reference.

The location of a fireplace mantel or surround made of any combustible material like wood (see my previous article Are Your Mantels Solid Wood) are governed by national or local building codes.

Building codes are written to provide builders with the information they need to insure public safety. There are specifications written for every conceivable element of your home, condo or apartment building. They specify what materials can be used and how construction is to be done and cover everything from the foundation, walls, roof, plumbing and electrical to how close your mantel can be to your fireplace. Before we dig into some actual building codes, let us look at some easy cases.

Mantels for Prefabricated Metal Fireplaces

The easiest answers do not require any research into building codes at all. When you are installing a prefabricated zero clearance metal fireplace, like the one shown here, the installation instructions will come with all the clearances needed for safely installing a mantel or surround. These are the most common type of fireplaces installed these days.

If you are replacing a mantel or surround installed around one of these prefabricated fireplaces and you are confident the previous installation was done correctly, you can probably safely place a new mantel the same distance from the firebox, especially if you never had a problem.

Work Done with Building Permits

When the work in your home is extensive enough to require a building permit, a building inspector will visit your job. The building inspector is not someone to be feared. In fact they can be a great resource to get guidance on the placement of a mantel. They should not only know the local code requirements, since they are the person who will likely sign off of the final approval they have a vested interest in getting the job done correctly so there are no future problems.

Stone Mantels and Other Non-Combustibles

The safety concern about mantel placement usually applies to mantels made of some combustible material like wood or MDF. Real stone fireplace mantels or cultured stone mantels like the one shown below do not burn easily and therefore can be placed closer to a firebox. You can focus more on aesthetics than building safety.

Fireplace Mantel Building Codes

As noted above, building codes have been developed to protect public safety. A mantel made of a combustible material must be installed far enough away from the firebox so it does not get too hot.

Most developed countries have a well thought out set of building codes that apply. In fact there is an international organization surrounding building codes: International Code Council

National building codes frequently borrow from the international standards and local codes are often based on national codes. Most large cities have their own set of building codes that are adapted to the local environment. If high winds are common, there will be a tighter code for tying a roof to the walls. If earthquakes are common there will be additional requirements to tie the walls to the foundation and for adding sheer walls to prevent swaying and possible collapse.

However, many small cities and towns around the country do not go to the time and expense to write, adapt or maintain their own set of building codes. Rather, they rely on the national building code.

Individual states also have building departments that are responsible for building codes. For example in California you can find the website at Here is the exact wording from the California Building code covering wood (combustible) mantels and surrounds when installed on a masonry (brick) fireplace:

R1001.11 Fireplace clearance. All wood beams, joists, studs and other combustible material shall have a clearance of not less than 2 inches (51 mm) from the front faces and sides of masonry fireplaces and not less than 4 inches (102 mm) from the back faces of masonry fireplaces. The air space shall not be filled, except to provide fire blocking in accordance with Section R1001.12.


  1. Masonry fireplaces listed and labeled for use in contact with combustibles in accordance with UL 127 and installed in accordance with the manufacturers installation instructions are permitted to have combustible material in contact with their exterior surfaces.
  2. When masonry fireplaces are part of masonry or concrete walls, combustible materials shall not be in contact with the masonry or concrete walls less than 12 inches (306 mm) from the inside surface of the nearest firebox lining.
  3. Exposed combustible trim and the edges of sheathing materials such as wood siding, flooring and drywall shall be permitted to abut the masonry fireplace side walls and hearth extension in accordance with Figure R1001.11, provided such combustible trim or sheathing is a minimum of 12 inches (305 mm) from the inside surface of the nearest firebox lining.
  4. Exposed combustible mantels or trim may be placed directly on the masonry fireplace front surrounding the fireplace opening providing such combustible materials are not placed within 6 inches (152 mm) of a fireplace opening. Combustible material within 12 inches (306 mm) of the fireplace opening shall not project more than 1/8 inch (3 mm) for each 1-inch (25 mm) distance from such an opening.





As you can read in the building code, a 12 inch distance should be maintained but when a 12 inch distance is not desired, then the following rule applies. The trim material can protrude only 1/8 inch for each inch away from the firebox. So, if you are using 3/8 thick wood trim, it must be a minimum of 3 inches from the firebox on a masonry fireplace.

Local Building Codes

It is a good idea to check for any local building codes but there is a good chance they will just refer to the national or international codes. A search of the Los Angeles Department of Building and Safety website for this article sends visitors to the International Code Council website noted above for building codes. If a large city like Los Angeles uses the ICC then there is a good chance most cities also do so.


From this research it appears that you will want to keep any combustible mantel at lease 12 inches above your firebox and more if possible or if the mantel projects more than 6 inches. For aesthetic purposes, the chances are you will want your mantel more than 12 inches above your fireplace anyway.

For fireplace surrounds use the chart above to determine the distance and thickness of the trim nearest your firebox. For prefabricated fireplaces use the instructions and for stone mantels just mount them where they look the best.

In all cases, check with your contractor if you have one and do at least a cursory internet search to see if your city uses the international standards. And finally, if you have pulled building permits, talk to the inspector.

Good luck, have fun installing your new mantel and give me call at 720-432-1238 or leave us a message on our Contact Us page and we will do our best to answer your questions or help with research.

<< More Fireplace Articles and Advice


© 2006 - 2015 Fireplace Mantels 123. All Rights Reserved.