How to Build a Brick Hearth for a Wood Stove

Things You\’ll Need

  • Measuring tape

  • Bricks

  • Pencil

  • 3-inch hardwood trim

  • Miter saw

  • 1/2-inch asbestos millboard

  • Dust mask

  • Utility knife

  • Straightedge

  • Construction adhesive

  • 24-gauge steel

  • Aviator snips

  • Mortar

  • 5-gallon bucket

  • Trowel

  • 1/2-inch notched trowel

  • Rubber mallet

  • Trim nails

  • Hammer

  • Mortar bag

  • Damp rag

  • Wood putty

Wood stoves are efficient sources of heat for a home and are safe as long as you install them correctly. Stray cinders or sparks can start fires in combustible carpet or wood flooring without the proper hearth. The proper installation always includes a fireproof hearth built large enough to accommodate the size of the wood stove.

Step 1

Measure out the area where you want to build your hearth. Take the depth and width of your wood stove and add 18 inches or more to both of them to arrive at the size of your hearth. The extra 18 inches is the minimum of most building codes for a safe hearth in protecting your floor from the risks associated with a wood stove. Situate the hearth at least 36 inches from any combustible walls and 18 inches from a fireproof wall.

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Step 2

Put down a layer of bricks to form a dry run, giving yourself a chance to perfect your layout. Laying the bricks flat creates a 2 1/4-inch layer of masonry to protect your floor. Leave a 3/8-inch gap between the bricks for the mortar. Measure the length and width of the actual area that the bricks cover. Mark the floor with a pencil, outlining the area.

Step 3

Cut 3-inch hardwood trim to fit the length and width of the bricked area for all four sides. Use a miter saw to cut 45-degree angles on the corners.

Step 4

Remove the bricks from the hearth area. Lay down a section of 1/4-inch fireproof millboard, cut to fit within the penciled outline. Cut the millboard outside with a utility knife and a straightedge. W ear a dust mask to protect against inhaling any asbestos fibers.

Step 5

Apply a bead of construction adhesive around the perimeter of the millboard. Place the millboard over the measured area for the hearth. The millboard insulates the floor from any excessive heat from the wood stove.

Step 6

Cut a piece of 24-gauge steel to fit over the millboard using aviator snips. Apply a bead of construction adhesive around the perimeter and set the steel over the millboard. The sheet of steel protects the floor from any cinders or sparks from the fire in the stove.

Step 7

Mix a batch of mortar in a bucket with just enough water to make a thick, but workable mixture using a trowel to mix.

Step 8

Cover a small area of the steel with a layer of mortar using a 1/2-inch notched trowel. Butter the back and adjoining sides of the bricks and set into the mortar, twisting them a quarter turn to set them into the mortar. Use a level to lay the bricks evenly, tapping them with a rubber mallet and leaving a 3/8-inch gap between the bricks. Continue laying the bricks over the mortar until you have covered the hearth.

Step 9

Add the hardwood trim around the perimeter of the hearth, nailing the edges together with trim nails, enclosing the bricks. Putty over the nail heads and finish as desired.

Step 10

Grout between the bricks with the mortar using a mortar bag. Fill in the gaps with the mortar and smooth flush with the surface of the bricks with a trowel. Clean off any extra mortar that gets on the surface of the bricks using a damp rag. Allow the mortar to dry for 5 to 7 days before setting the wood stove on top of the brick.