Tiling Around a Fireplace
This is the job people book in the winter, and it is the one where a misunderstanding can cost a homeowner more than the tile. Tile belongs on a fireplace hearth. The part that needs care is the joint between the hearth and the floor, and the part that has nothing to do with tile is the clearance behind the wall.
The Short Answer
Tile Is Fine Around a Fireplace. A Clearance Problem Is Not a Tile Problem
Tile is a noncombustible finish, which is exactly why it is allowed on a hearth and around a masonry fireplace. It does not burn, it does not scorch and it does not carry heat the way wood and drywall do. So the material is the right one.
The two things that cause trouble are the movement joint where the hearth meets the floor, and the clearance between the fireplace and whatever is behind the wall. Both of them get decided before a single piece of tile is cut.
What the Heat Does
Where the Heat Goes, and What It Does to the Tile
The heat in a wood burning fireplace goes up the flue. That is the design. It leaves through the chimney and it does not come out the front of the firebox. So the front of a masonry fireplace is not a hot face in the way a wood stove is.
What reaches the room is the heat that comes off the glass and out of the firebox opening, and the rising warm air that collects at the ceiling. On the floor in front of the fireplace, the effect is a warm zone that cycles with the fire. Cold air comes in low, warm air goes up.
Why Cycling Heat Cracks Tile
That cycling is the part that matters for tile. Everything on a hearth expands when it warms and contracts when it cools. Over a season, and over a few years, that movement adds up. A tile floor that is locked tight to something that moves a different amount ends up taking the difference in tension, and tension in tile means a crack.
Gas Fireplaces Are a Different Machine
A gas fireplace is a different machine. It puts less radiant heat into the room and no wood smoke, but the unit and the glass still get hot, and the fireplace listing still sets the clearance. Ask which kind it is before you plan the tile.
The Clearance Rules
The Hearth Extension, in Plain Terms
Connecticut adopted the 2022 state building code, which is based on the 2021 residential code. For a masonry fireplace, section R1001.10 sets the size of the hearth extension. It has to extend not less than 16 inches in front of and not less than 8 inches beyond each side of the fireplace opening. Where the opening is 6 square feet or larger, it becomes not less than 20 inches in front and 12 inches beyond each side.
How Thick the Extension Has to Be
Section R1001.9.2 covers how thick the extension has to be. The minimum is 2 inches. There is an exception, and this is the one that matters for tile. Where the bottom of the firebox opening is raised not less than 8 inches above the top of the hearth extension, the extension can be as thin as three eighths of an inch of brick, concrete, stone, tile or other approved noncombustible material.
When a Thin Tiled Hearth Is Allowed
So a tiled hearth is allowed, and the tile is allowed to be thin, provided the firebox opening sits high enough above the tile. The hearth itself is a thicker slab than the extension in front of it, which is why there is usually a step between the two.
Factory Built and Gas Fireplace Clearance
For a factory built fireplace or a gas unit, the clearance comes from the appliance listing rather than from this section, and the wall has to be built to meet it. Here is the part worth remembering: the clearance is measured to the combustible material, not to the tile. Putting tile over a wall that is inside the clearance zone does not fix the clearance. It hides it, and it puts tile where it should not be.
The Substrate and the Gap
The Joint That Saves the Job
A hearth is normally a slab of concrete or masonry, sometimes with brick or stone on top of it. The tile goes on that slab in a mortar bed or a thin set. The slab is what carries the heat and what takes the weight, and it is not the part that moves.
The Floor Around the Hearth Moves
The floor around it is a different story. A wood floor expands and contracts with the season. So does the tile. And they do it by different amounts.
- Leave a joint where the hearth meets the floor. It is filled with flexible sealant, not grout, and it lets the two surfaces move independently.
- Leave a joint where the tile meets the vertical face of the hearth breast, for the same reason.
- Do not grout those joints. Grout is rigid, so it takes the movement and cracks, and a cracked joint next to a fireplace is a joint that collects dirt.
- If the hearth is a floating slab, it is isolated from the framing. A slab that is tied into the framing moves with the house and cracks at the corners.
What the Code Does Not Cover
The code sets the size and the thickness of a hearth extension. It does not say anything about a slope. Water still has to get off a tiled hearth, so ask how the tile is laid to shed it before the work starts.
Questions to Ask
The Code Questions Worth Asking
- Is this a masonry fireplace or a factory built one, and is it wood burning or gas? The answer decides which clearance rules apply.
- How big is the fireplace opening? Under 6 square feet or over it, the required hearth extension is a different size.
- Is the bottom of the firebox opening raised at least 8 inches above the top of the hearth? That is the condition for the thin, tiled extension.
- What is behind the wall behind the tile? If the surround is on a framed wall, the clearance question has to be answered before the tile goes on.
- What is happening with the chimney and the flue? If the fireplace is being converted from wood to gas, that is trade work and it is not in the tile bucket.
- Does the building department in your town want a permit for any part of this? The tile is usually exempt. Anything past the tile is not.
Before We Start
What Gets Checked Before the First Tile Is Cut
- The type of fireplace and whether it is in use. An unused chimney and a working one get treated differently.
- The existing hearth. Is it brick, stone, tile or bare slab? Is there old mortar or adhesive to remove? Is the slab solid?
- The height of the firebox opening above the hearth, and the size of the opening against the required extension.
- The wall behind the surround. Framed, masonry or a combination, and what is on the other side of it.
- The floor outside the hearth. Where the movement joint goes, and what the tile has to meet at the edges.
- How the work is staged. A hearth in the middle of a living room has to be protected from the traffic and the dust of the rest of the job.
What Goes Wrong
Four Ways a Fireplace Tile Job Goes Wrong
- The tile runs tight against the wood floor with no movement joint. The joint cracks, or the tile cracks, and it happens on the same line every winter.
- A hearth extension that is smaller than the opening calls for. That is a code problem. It does not matter how good the tile looks.
- Tile put on a wall that is inside the clearance zone. The tile is not what makes the wall safe, and a new tile face can hide a problem that was there before.
- A joint packed with rigid filler where a flexible one belongs. Expanding foam and hard grout in a movement joint is a way of building in the crack.
What to Do Next
Get the Fireplace Measured Before the Tile Is Ordered
Send us a photo of the fireplace, the width of the opening, and the floor around it. We will tell you what the hearth extension has to cover, where the movement joint goes, and whether the wall behind the tile is a question somebody else has to answer.
What Happens on the Estimate
On the estimate we write down what is behind the tile, not just what is on top of it, so there are no surprises in the middle of the job.
Frequently Asked Questions
Tiling Around a Fireplace - Questions
Yes. Tile is a noncombustible finish, and the code allows a hearth extension of brick, concrete, stone, tile or other approved noncombustible material when the bottom of the firebox opening is raised at least 8 inches above the top of the extension. That condition has to be met for the thinner extension to be allowed.
The 2021 residential code says a masonry fireplace hearth extension has to extend not less than 16 inches in front of and not less than 8 inches beyond each side of the fireplace opening. Where the opening is 6 square feet or larger, it becomes not less than 20 inches in front and 12 inches beyond each side.
It depends on what is behind the tile and what the fireplace listing requires. The clearance is measured to the combustible material, so tile on a framed wall does not fix a clearance problem. Where a wall is inside the clearance zone it has to be a noncombustible assembly, and the fireplace has to sit further back.
Because there is no movement joint there. Tile and a wood floor move by different amounts and in different directions, and when they are locked together one of them cracks. The joint between a hearth and the floor around it is left open and filled with flexible sealant so the two can move separately.
The tile work itself is usually in the same exempt bucket as other finish work. Anything beyond the tile, such as changing the hearth structure, the firebox or the flue, is not finish work and has to go to your building department. We tell you which parts of the job are which before we start.
Still have questions? Call us at (860) 990-2332
Where this work gets done
Custom tile installation, How a tile installation goes by Dmtilellc across Connecticut. Ask for a free estimate.
Let Us Measure the Hearth and Show You Where the Joint Goes.
If you are in New Britain, Berlin, Newington, Plainville, Farmington, Avon or a nearby Connecticut town and need tile installation, bathroom remodeling, shower waterproofing, backsplash work, or floor tile installation, contact Dmtilellc today. Free estimates available.