How to Install a Wood or Coal Stove

small wood stove on hearth pad in front of stone wall

With the cost of heating your home going up seemingly daily and the reliability of our electrical grid in question, more and more people turn to wood and coal stoves as a main or at least a backup source of heat.

After all-fire has worked as a heat source for thousands of years, and wood is as renewable as it gets. Plus-what is more relaxing than spending an evening in front of a fireplace?

The problem with installing a wood or coal stove on your own is that you're working on a project that will regularly heat up to over 2000 degrees. You'll be placing it within close proximity of highly flammable walls, roofing, and, well, just about everything else in your home.

This is a job where getting it done right and done right the first time is as close to mandatory as it gets.

Let's take a step-by-step look at what it takes to install a wood or coal stove safely, efficiently, and without catching your home on fire.

Minimum Fire Requirements and Location

Your stove will radiate heat to its surroundings as you burn wood or coal. Wouldn't be much point in having one if it didn't-it's why we go through the trouble of installing it.

The problem comes up when a surface around it absorbs enough heat to raise its temperature significantly and start a fire. This is why the rules on distances from flammable objects are stressed by stove manufacturers, code inspectors, and fire departments.

The first step is determining where the stove is going to go in relation to the flammable walls and other objects around it. Look on the back of your stove for a certification label.

If it has one, the stove is "listed,"-meaning the manufacturer did multiple tests to determine the minimum distances this particular model can be placed from flammable objects. The numbers should be right on the label, as well as the recommendations for the type of hearth needed to protect the floor.

If your stove is older than 25 years, the label has been removed, or you've bought a homemade contraption-the National Fire Protection Association recommendations will apply, and the distance to the walls will depend on your willingness to add heat protection to the flammable surfaces. :

  • No fire protection-36 inches to the nearest combustible surface from the stove/18 inches from the pipe
  • A cement board with 1 inch of space behind-18 inches from the stove/12 inches from the pipe.
  • 28 gauge steel with 1 inch of space behind-12 inches from the stove/9 inches from the pipe.

A well-built fire protection will consist of a layer of non-flammable material(steel, cement board, etc.) that's positioned 1 inch away from the wall with the bottom edge spaced 1 inch from the floor for air circulation. Keep in mind that the spacers that keep your chosen fire protection away from the wall can not be flammable themselves-wooden strips will negate the exercise.

Metal joists or strips of cement board cut 2 inches wide and sandwiched together to generate 1-inch thickness (it'll usually take two board strips).

wood stove installation in open wall

Hearth and Fire Protection

A hearth will protect the floor from catching fire, keep the smoldering embers off the floor and add a touch of old-world cool to the aesthetics of the room.

You will need to build up the thickness of the hearth according to the stove manufacturer's requirements or the general National Fire Protection Association minimum standards, as well as the dimensions to meet the code and protect the floor.

If you don't have a label to go from, the standard is to extend the hearth 18 inches to the front and back of the stove(if you're working with a round stove, the front is the side with the opening) and 12 inches to the sides.

The thickness and construction of the hearth will depend on how far the bottom of the stove is located from the ground.

If the floor you're setting the stove on is not fireproof(made out of stone or concrete), it's recommended to place a 24 gauge metal sheet on top of the floor under the stove. The sheet does not have to be the full size of the hearth but should, at the minimum, match the dimensions of the stove. On top of the metal sheet:

  • Stoves with legs 6 inches and taller will do fine on 1-2 inches of the fireproof material-cement board, tiles, etc.
  • Stoves with less than 6 inches will need 4 inches of masonry, preferably hollow, to allow for air circulation beneath the stove.
  • Another option is to build up the carcass of the hearth, 4-6 inches tall, providing air circulation under the platform, and then a fireproof surface on top, 1-2 inches thick.

Whatever you've chosen as the top layer for your hearth, make sure the surface is continuous, without cracks or spaces to meet the code, and prevent a stray ember from falling through and reaching the floor.

Chimney and the Stove Pipe

Your stove's chimney's main job is to move the smoke out of your home, but it's also responsible for creating a proper draft( the pulling force moving the smoke up and out of your chimney), allowing the wood or coal to burn properly.

A well-designed chimney will keep as much heat as possible from escaping outside your home into thin air above it and, hopefully, keep the fire in your stove from setting your roof on fire.

Your chimney/stove pipe will consist of three major sections:

Stove Pipe

The inside, non-insulated stove pipe leads from the stove itself to the ceiling of your room. This part of the chimney pipe is usually single-walled and made out of 24 to 28-gauge steel. Its purpose, besides moving the smoke out of the house, is to radiate leftover heat into the room before it gets wasted into the cold air outside.

Chimney Support Box

The middle part of the chimney, the chimney support box, is designed to connect the inside pipe with the outside section while keeping the highly flammable wooden joists and insulation populating your ceiling from catching on fire. It usually comes with a metal outside box that positions the pipes at a sufficient distance from the parts of the roofing assembly.

Exterior Chimney

The part of the chimney you'll see sticking out above the roof is usually insulated or double-walled in an effort to prevent cold outside air from extinguishing the fire in your stove. As the air drops in temperature, it gains in weight, making the outside air in the colder months you're likely to be using a stove much colder and heavier than the air attempting to come up from your wood stove.

Once the stove is running nice and hot, the temperature of the outside air is not much of an issue, but a well-insulated outside pipe is a huge help in starting a fire in your stove without filling the house with smoke.

The other consideration when picking an outside chimney pipe is the height. To develop a good draft and meet the building code, a chimney should come up 2 feet higher than any spot on your roof within ten feet. The best draft is usually achieved at the peak of the roof, but that also makes for the hardest installation.

Installation Process

Start the installation by deciding how you're going to run the stove pipe straight up through the roof or run it through the wall and coming up outside it. Most of the time, the architecture of your home will help you make that decision.

Keep in mind that straight-up installation is usually preferred since it allows more heat to stay within the room and creates a better draft, but it will put you in a position where you'll have to make a huge hole in your roof, inviting the possibility of leaks. Traditional and the most effective position is right in the center of the house, allowing you to retain the most heat and generate the strongest draft.

  • Once the stove is in position on the hearth, grab a step ladder and a plumb bob(or a piece of sturdy string with a weight on the end) and position it on the ceiling above the chimney pipe opening on your stove. Adjust the position until the plumb bob hangs directly above the center of the opening. Mark this point.
  • Cut the hole for the support box centered on the point you've just marked-be careful to stick close to the dimensions of the box when cutting the opening-with most kits, you don't have more than an inch or so to the side of the box that will be covered by the trim. This is definitely the "measure thrice and cut once" situation.
  • Using the plumb bob once again, cut a hole in the roof itself that lines up with the opening you've cut for the support box and the stove. The easiest way to do that is to use a drill with a long wood bit to drill the center from the inside and then cut a hole from the outside of the roof using a sawzall, jigsaw, or a handsaw. keep the opening a touch larger than the chimney pipe you'll be using.
  • Install the support box, attaching it to the ceiling joists using a 1 1/2-inch screw. Build up blocking using two-by-4s if the joists are too far away from the location of the support box. Move the insulation away from the chimney pipe-it's ok for it to touch the support box, but insulation next to the stove pipe will be a serious fire risk.
  • Install the outside part of the stove pipe into the support box, twisting it in place. Pull up the shingles directly around the pipe, run a bead of silicone on the underneath of the roof flashing, and slide it over the pipe. Run another bead over the top of the flashing and place the shingles back in place. Using roof screws, attach the flashing to the roof. Silicone over the screw caps.
  • Assemble the full height of the outside chimney pipe by placing the male end into the female and twisting them together until they click together.
  • Run a bead of silicone on the inside surface of the storm cap and slide it over the stove pipe.
  • Attach a rain cap over the top of the stove pipe and screw it in place.
  • If your chimney pipe extends over the roof more than 2 feet, attach a set of metal supports to the pipe and screw them to the roof. Don't forget to silicone the tops of the screws.

With the outside section of the stove pipe in place, it's time to get inside and connect the stove to the support box.

  • Use a telescoping section of the black single-walled pipe to connect the male end of the adapter to the female end of the pipe. Use a level to make sure the pipe is installed straight.
  • If your stove pipe did not come preassembled with a stove damper, you'll want to install it before going any further. A damper will let you control the flow of air into the stove, allowing for a more effective burn. Drill two holes in the pipe opposite each other, the size of the damper rod. Thread the damper into one side and attach the damper flap. Thread the damper rod into the opposite side of the stove pipe wall.
  • Add extension pieces of the pipe until you reach the stove. Insert the bottom pieces' male end into the stove. Make sure that the male opening on the pipe pieces is always facing down to avoid creosote leaking out of the joints.
  • Use two self-tapping screws to reinforce each joint between the pieces.
  • Attach the trim that came with the support box around its perimeter.

With the new stove in place, it's a good idea to burn a couple of small fires to cure the new paint and season the firebricks. Start a fire using wooden kindling and let it burn out. Repeat a couple of times. This also allows you to make sure the stove is operating properly, you're getting a sufficient draft, and there are no smoke leaks inside the house.

Installing a wood or coals stove, while a sizable project, is completely within the capabilities of an average DIYer. Take your time, make sure you understand the position and function of each piece you're installing, split the project into manageable pieces, and you'll be enjoying the warmth and comfort of your new stove in no time.