Ask the Builder: Rehabbing your fireplace
By Tim Carter,
I have an old rock fireplace that I hate. The built-in heat-a-lator has also stopped working. I want to change the rock face to one that’s wood. I have some extensive woodworking experience, so is it possible to make these fireplace repairs myself? Can I build a wood frame over the rock and disconnect the gas log-lighter in the firebox? —Suzanne H., Richmond
Fireplace restoration can be an enormous job. I always say that anything is possible if you have enough resources, which sometimes includes lots of money. This job, however, needs abundant skill, time and a deep knowledge of the building code.
The quick answer is that it’s possible to do what you want. You can transform the exterior look of the fireplace. But I would caution you about removing the gas log-lighter. A future homeowner may want this convenience.
Many masonry fireplaces are constructed much like the way cars were built before the advent of unibody construction. There was a chassis or frame and the body skin of door panels, fenders, quarter panels, etc. All were bolted to one another and then to the frame.
Fireplaces are somewhat like this. Modern masonry fireplaces often have a concrete-block core that contains the clay flue liners and a firebox made with high-temperature firebrick. The outer skin can be rock, brick, wood, plaster, drywall or what have you. These materials are attached to the concrete-block core.
Assuming you have a masonry fireplace constructed with a block core, your challenge is to see what’s easier: removing the rock facing or building a code-approved wood frame out beyond the rock.
If you decide to attach your finished wood to a wood frame that’s attached to the rock, you may find that the thickness of the wood frame and finished wood skin causes the firebox to be more deeply recessed. Aesthetically, that may be undesirable. It could also be a building code issue.
Before you do anything, you need to visit your local building department and get a copy of the current building code. Take photos with you and meet with the building inspector or the head of the building department. Remember, these are public employees;it’s their job to assist you and answer your questions.
You want to be crystal clear on all the clearances mandated in the code with respect to the proximity of combustible materials to the firebox. Don’t leave this meeting unless you completely understand what the minimum requirements are. Make drawings there and have the building inspector sign them or otherwise approve your understanding.
You’ll discover quickly that the code talks about horizontal and vertical distances to things that burn. It also may have a section that talks about maximum overhang of combustible materials.
Once you have a firm understanding of these code requirements, take the time to draw a simple scale plan of what you’re allowed to do. See if is going to look right. Make sure to do a side elevation (that is, drawn as if you’re looking at the fireplace from the side). This will be on a scale that measures perhaps 1 inch to 1 foot. You only need to draw from the hearth up to about 3 feet above the mantel. This will give you a good idea of the mass of the new exterior skin.
As for the heat-a-lator, you’ll have to determine if the fans are bad or if it’s some other electrical problem. If there are no fans and it’s just a gravity air-convection system, perhaps you can determine why there is no or little airflow as you take apart the fireplace. It could have been poorly designed from the get-go, and there may be little hope of making it work without a massive reconstruction effort.
You’ll have to incorporate a new stone material that surrounds the firebox and transforms to the wood. You may choose to use a natural stone like marble or granite for this. You can also use ceramic tile. We had a fireplace that had a green serpentine marble surround that complemented the walnut wood surround. Our living room fireplace had a traditional decorative ceramic tile facade just outside the firebox.
All of these treatments usually need perfectly smooth surfaces to bond the tile or the stone to the fireplace core. You’ll have to engineer all of this into your plan before you start the job. This may require you to tear off all the stone to get to thecore of the fireplace. Be prepared to punt frequently, as you’re entering unknown territory.