Trying to figure out what kind of pipe you need to install for your fireplace, stove, or any other venting hearth appliance can be a daunting task.
The pipe needs to be a specific size in order to exhaust properly. You can’t mix different brands or metals or sizes. Plus, you need to make sure the pipe is fit for the type of fuel you’ll use.
There are plenty of other rules like these that contribute to the difficulty in buying chimney pipes. Today’s post will help you become a bit more familiar with chimney pipes.
What is a Stove Pipe?
A stovepipe is not the same as a Class A chimney pipe, although these two are often confused with each other.
Stovepipe is used for venting wood-burning stoves and is only for use inside your home, or more specifically, inside the room where the stove is installed.
Once the venting reaches the wall or ceiling, it must be converted to Class A chimney pipe. Depending on the type of stove pipe you use — single-wall or double-wall — you must also account for the proper clearances from combustibles.
For example, a single wall stove pipe requires an 18-inch clearance from ceilings or walls.
However, double wall stove pipe only requires 8-inches of clearance from the ceiling and 6 inches from a wall.
Once these clearances are met, you must convert your stove pipe to Class A chimney pipe for proper venting of your stove.
Many stove owners we talk to are actually surprised when we tell them the stove pipes are never permitted to go through the ceiling or the wall. No matter how much clearance you can create.
Therefore, it is never safe to use only stove pipe for venting.
If used outside, the stove pipe won’t be able to maintain the high flue temperatures required to adequately vent the gases. This will cause excessive creosote buildup and increase the risk of a chimney fire.
Class A chimney pipe only requires two inches of clearance because it is made to handle the highest temperatures for exhaust.
This is why you must convert from stove pipe to class A chimney pipe when you’re venting your wood stove.
How to Install a Stove Pipe Into a Chimney
There are a couple of different ways to make the conversion from a wood stove pipe to a chimney pipe for proper venting.
These include through-the-ceiling and through-the-wall venting methods.
Each installation calls for different components, depending on the transition point between the stove pipe and the class A chimney pipe.
For venting systems that run vertically through your ceiling, you’ll need to have a ceiling support box or round ceiling support piece to use as your transition point from the stove pipe to the class A chimney pipe.
The stove pipe will connect to the bottom and the class A chimney pipe will simply attach to the other side, either running through the ceiling support box itself or an attic insulation shield (in the case of round ceiling support.
From here, chimney pipe will pass through a pitched roof by use of roof flashing, or it can be built into a framed wooden chase, which must be topped off with a fabricated chase top flashing.
For venting systems that run horizontally through the wall, you’ll need to have a thimble.
A thimble is designed to that Class A chimney pipes can pass through the wall, run into the room where your appliance is installed, and then connect to the stove pipe.
If you have a double-wall stove pipe, the Class A chimney pipe must come into the room six inches. But if you have a single-wall stove pipe, the class A chimney pipe must come into the room for 18 inches.
Most wood burning stoves that we see are top-vent models, which mean the flue collar will be on top of the unit.
For any horizontal, through-the-wall venting system, you’ll need to have at least 12-inches of vertical rise from the top of the stove before connecting a 90-degree elbow piece to turn toward the wall.
Some older wood burning stoves are rear vent models, which require the use of a tee for cleanout purposes at the flue collar.
Like top-vent models, they require a minimum of 12-inches of vertical rise before directing the vent pipe horizontally.
In addition to the pipe and termination cap, there are still several components that you may need for the installation of your new chimney pipe.
Elbows are often needed in chimney systems for a variety of reasons.
Unless you are able to vent your chimney system vertically or horizontally without any obstructions blocking your path, you are going to need an elbow of some kind.
All manufacturers specify the offset parameters for each hearth appliance in the owner’s manual. So you’ll want to consult your manual for this specific information regarding your unit.
Elbow Strap/Wall Strap
Many manufacturers provide elbow straps for many kinds of pipe to support chimney systems with offsets.
You’ll use wall straps — one every 4-5 feet of vent rise — when running a direct vent chimney pipe vertically inside a chase or alongside a wall.
Ceiling Support Box/Thimble
These components are necessary for use when the pipe is exposed and exiting the room where the appliance is located.
If you are venting vertically through the ceiling/roof, you will need a ceiling support box or a round ceiling support. If you are venting horizontally through the wall, you will need a thimble.
In direct-vent systems, these will be used only for support, as there is no transition to another kind of pipe.
Firestop/Attic Insulation Shield
When passing through a ceiling, floor, or attic, you will need to use one of these components.
If ceiling support is not used, the firestop is required for passing through ceilings in multi-story homes, while the attic insulation shield is required when passing through an attic.
Both of these pieces ensure your pipe maintains proper clearances as it passes through combustible ceilings and floors.
Chimney Tee/Tee Support
When your chimney system passes through the wall, you will need a tee and tee support to serve as a 90-degree bend to turn your chimney up toward your roof.
Placed underneath the flashing on the roof, the roof support is designed to support pipe both above and below the roof.
There is a limited amount of pipe it will support, particularly below the roof, but this component is ideal if you do not have a ceiling support box as part of your system.
A flashing and storm collar go hand-in-hand. They are designed to protect your chimney system from weather damage.
The flashing is the piece that covers the hole in your roof where the pipe penetrates. The storm collar fits around your pipe just above the flashing to prevent rain or snow from getting into the minuscule crevice between your flashing and pipe.
You need to select a flashing appropriate for your roof pitch. A roof pitch is a measurement of vertical rise over a horizontal distance of 12 inches.
For example, if your roof has a vertical rise of 3 inches over a 12-inch horizontal distance, your pitch is 3/12.
Extended Roof Bracket
When your chimney extends more than 5 feet above your roof, you need an extended roof bracket to provide stabilization for your pipe against the wind.
How to Hire a Chimney Contractor
When you’re ready, you should schedule a time for a certified chimney expert to go to your home to take a look at the area you want your new class A chimney installed.
You can easily reach out to your local chimney company and have a done-for-you solution in no time!
But navigating through all of the chimney companies in your city can be a chore all on its own. And it makes sense, too.
Hiring anyone to come into your home to install a heat source involving fire shouldn’t be a task you take lightly. So I created a list that you can use to make sure you make the right decision when you need someone to help you in your home.
Questions to Ask
When you’re hiring a chimney company, you should always ask the following questions before allowing them to come into your home:
- Can the company provide references?
- Does the company carry a valid business liability insurance policy?
- Does the company ensure that a certified chimney technician will be on the job?
If they guarantee all three of those, then you are in a good spot. The technicians don’t necessarily need to be certified by the CSIA, but I do recommend putting in a bit more due diligence before accepting a certification that’s not by the CSIA.
This is because certifications are a tricky thing, especially in an unlicensed industry like ours. Any company can craft a list of job-related questions and sell them as an exam and certify those who pass.
I recommend you take a few extra minutes in your research before making your hiring decision to learn more about the certification the company has. Here are a few tips to make sure the certification is reputable:
- Is the word “certified” just part of the business name or is it an earned designation?
- Is the certifying body a for-profit business or non-profit?
- Does the certification need to be maintained and renewed through continuing education as the industry evolves, or is it well enough to be certified through a one-time exam?
- Is the certifying body well-established or are they relatively new to the scene? New doesn’t mean “bad” but you should make sure the requirements for certification are more or at least equally stringent as those of more established certifications
- Is the mission statement of the certifying body focused on educating and protecting homeowners or is it more focused on making it easier to earn a certification?
- Does holding the certification require following a code of ethics?
If you can answer all of these questions, then I think it will be safe to allow the company in your home to work on your chimney.
Please note that If you are hiring a chimney company to install a cap for you, most of the time, they will need to buy the cap themselves. This is primarily for liability and insurance purposes.
It doesn’t matter if you are in Roanoke, Lynchburg, Blacksburg, or some other city anywhere in the USA — if you have any questions about the safety of hiring a chimney company, please don’t hesitate to email me at email@example.com or call me at 540-225-2626. I’m happy to help!