Asked on Sep 13, 2012

How to build a solid granite stone hearth for underneath a wood stove?

Jason Schiffner
by Jason Schiffner
We intend to hire professionals to install a wood stove, but we want to save money and build the hearth ourselves. We want to build the hearth of one solid granite stone and not tiles. There is plenty of information on the internet on how to build a tiled hearth, but none about one made of a solid stone. We only want the hearth under the stove (less money and space used this way).
We chose Lopi's Cape Cod as the wood stove we want. Attached is the picture and a link to the website below. The minimum dimensions for the hearth under this stove are 41 3/4" x 44 1/4". The non-combustible flooring need only be .018" thick. Ideas?
Lopi's Cape Cod Wood Stove
  7 answers
  • Before you reinvent the method of installing a hearth, Although I see no real issue with a solid stone being used. Check out some of the photos I provided so you understand the basic clearances required. I would also check with both the stove manufacture as well as the local building department on their requirements for clearances to combustible materials or you may end up with something that may look great, but cannot be used due to safety issues. You will notice different requirements for floor protection depending upon the leg length of the stove. Just understand that these are a sample of how it needs to done. Your stove install requirements must be followed.
  • KMS Woodworks KMS Woodworks on Sep 14, 2012
    A single slab of granite that is roughly 4 feet by four feet is about 1/2 of a commercial slab ( that you might use for kitchen counters etc) These are generally 3 cm thick. You might be able to find some thinner stock but with thinner material comes a weaker slab. The cost to purchase a slab may run 15 to 35 bucks a sq foot plus what ever edge treatment you want. I have polished many stone edges and all that you would need are low speed grinder and full set of diamond polishing pads. Those tools might set you back a couple hundred. Since you are only doing 1 slab you may find the price more economical to have it polished for you. Another thing about working with a big slab is they a very heavy and moving them about is a pain with out a handful of big strong arms and backs...tile is easy by comparison. one thing I like when working with granite tile is the ability to create pattern and design. Here are some wood stove hearths I've done
  • Jason Schiffner Jason Schiffner on Sep 14, 2012
    I am comfortable with the clearances and I have a copy of the owner's manual. My plan for the slab will give me some extra room on all the sides. The minimum is 6" for sides and back and 16" for front and I'll make it about +2" on all sides depending on the granite slab we find. I want to build a floating hearth slab. Similar to the kind one could purchase from the store. It will simply rest over the carpet. I'm not ready to rip out carpet and I'll build a decorative wall behind it another day. For a tiled slab the steps to build consist of plywood, cement backer board, cement or mortar applied with trowel, tiles, grout, then edge. I'm thinking to follow all the same steps minus the grout. The edge I make will only cover the plywood and cement backer board. I will pay for the granite dealer to give the stone a very nice rounded edge. Lastly, the requirements of the stove for flooring are only .018" inch of noncombustible material. But I will buy the thickness the granite dealer recommends is best for the integrity of the stone. 3cm or so is what I imagine.
  • Carpet next to a wood stove is not the greatest of ideas. However if you are planning that move, purchase a low cost fireproof carpet runner that can be placed in front of the stove when its being used. Any spark that files out from the front when the door is opened, can result in a carpet burn quite quickly. The noncombustible material thickness does have any thing to do with clearance issues. If you used a half inch thick slab of steel, and it was to close to the stove, the floor under will still burn. Just be sure about that clearance and get the local code approval as well. Quite often then not they have their own set of rules for this. Be sure to take photos before, during and after and post them here for everyone to see! Good luck.
  • Jason Schiffner Jason Schiffner on Sep 14, 2012
    Good tips. My main question is do you think I should attach the granite stone to the cement backer board and plywood as if it were tile?
  • No reason I can see why you would. As long as your floor is strong enough to support the weight of the stone and stove. Any trims used will prevent the stone slab from moving, or simply use some contractors adhesive in a few small dabs just to prevent sliding, which most likely will not happen.
  • KMS Woodworks KMS Woodworks on Sep 15, 2012
    every code I have read for a wood stove has a min 18" of clearance in front of the loading door. And from a practical use point of view having 2 wood stoves in my home and a lifetime of their use...I would recommend at least 2 feet in front...and then would NEVER consider having a stove in a carpeted room. I have seen coals "jump" out over two feet...In my living room ( pictured above) the tile extends out about 28" and even then coals have gone out onto the hardwood floor. The hardwood extends out from there another 18" or so before it meets the area rug....with the tile being set at the same height as the hardwood it is easy to quickly push a coal back onto the tile...even with a bare hand...then get the ash shovel and scoop it up ...if your pad is higher than the carpet this quick response is not going to happen. The wood stove I installed in our cabin is on a complete tile floor and the easiest to maintaine...aside from the fire issues clearances etc. Wood stoves are dirty...ash will fall out when cleaning, transferring to the ash bucket etc. uniform height tile ( or tile wood combo) is far easier to keep clean. I have been burning 5 to 6 cords each year for a bout 20 years now...needless to say I have a bit of experience with fires in wood stoves.