Chimneys are typically vertical, or as near as possible to vertical, to ensure that the gases flow smoothly, drawing air into the combustion in what is known as the stack, or chimney effect. ... The height of a chimney influences its ability to transfer flue gases to the external environment via stack effect.

Why do chimneys need to be tall?

The main issue with chimney height has to do with draft. If the chimney is not tall enough, your fireplace will suffer from inadequate draft and not function properly or safely. The column of rising hot gases inside your chimney will not be able to develop a safe and adequate draft.

Does the height of a chimney matter?

It is often better to make the chimney taller to avoid wind turbulence. A good objective is to have the top of chimney above the roof peak, and this is much easier if the chimney penetrates the roof near the peak.

Can a chimney be too tall?

A chimney that's too tall can result in the heated air cooling off by the time it reaches the top of the chimney stack. This can create a negative pressure inside of the smokestack that pushes smoke and other gases back into the home.

Does a higher chimney draw better?

The two main things that contribute to draft size are:

The reason that a taller chimney creates a better draft is really rather simple as the higher up in the atmosphere the chimney reaches, the greater the differential pressure.

Is your chimney the right height?

15 related questions found

Can a flue be too big?

When a flue is too big, the chimney can be too cold. Cold chimneys make keeping a fire lit more difficult. They also lead to condensation and possible mold inside the chimney brickwork. They key to making and keeping a great draft in your fireplace is making sure the proper sized flue is installed.

What is code for chimney height?

Chimneys must end at least 2 feet above any section of the building within 10 feet of them, and must be 3 feet above the section of roof it is built through.

Can a wood stove chimney be to tall?

Chimney Height and Draft

The chimney should extend at least 3 feet above the roof surface it penetrates and 2 feet higher than any roofline or other obstacle within a horizontal distance of 10 feet. Taller chimneys make more draft, but chimneys exposed to outside cold don't.

Does a chimney have to go straight up?

6 Answers from MyBuilder Chimney & Fireplace Specialists

The straighter the chimney the better it works and at least 80% of the chimney must be vertical. In a factory made system (twin wall flue) there can be a maximum of 4 bends with a 45 degree bend counting as one and a 90 degree bend counting as two.

What is the 3 2 10 Rule chimney?

This rule means that your chimney's shortest side needs to be at least 3 feet above the roof penetration, and its top has to be 2 feet higher than any part of the building that's within 10 feet.

Is there a minimum height for a chimney?

The minimum chimney height recommended for minimum performance of wood burning and multi fuel appliances is 4.5 m from the top of the appliance to the top of the chimney. ... It is best to position the chimney, so that it goes straight up as near to the roof ridge as possible.

How do I improve my chimney draft?

11 Quick Ways To Help Improve The Draw On Your Open Fireplace

1. Have The Chimney Swept. ...
2. Open Any Air Vents Or Windows. ...
3. Fully Open The Damper. ...
4. Leave Glass Doors Open Before Each Fire. ...
5. Prime The Chimney Flue. ...
6. Build A Fire Using The Top-Down Method. ...
7. Use Low Moisture Content Logs. ...
8. Burn Smaller, Hotter Fires.

What causes a chimney not to draw?

The main reasons why your wood stove does not draw can include: The stove or flue is too cold. The flue or chimney is dirty. The room or house is too airtight.

Should a chimney have a bend?

Bending a chimney's exhaust pipe is not recommended as it can cause damage to the entire chimney. Apart from this, a chimney is meant to offer a proper inflow of oxygen to help in combustion and the outflow of gases and fumes.

What size are most chimney flues?

It is available in several sizes. The most commonly used sizes in residential construction are 8 by 8 inches, 8 by 13, and 13 by 13 (outside dimensions). Flue tiles are connected together with cement mortar joints, struck smooth on the inside.

What is the 2 10 rule?

If you are farther than 10′ away from the peak, your chimney needs to be 2′ above the highest point within 10′. For example, your chimney is exiting 20′ away from the peak and you have a 6/12 pitch roof.

Why is smoke coming in from fireplace?

A smoking fireplace is the result of chimney draft issues. ... The air inside your home pushes air up the chimney, like a vacuum. Good draft conditions allow vented smoke to travel up the chimney quickly, while poor draft conditions can cause smoke to billow back out into your home instead.

How do you test a chimney draw?

The smoke test involves the following steps:

1. If there is an appliance fitted at the base of the chimney, burn some newspaper in the grate for 2 to 3 minutes to establish a flue draw. ...
2. Place at least two flue testing smoke pellets on a brick in the opening at the base of the flue or in the appliance if it is fitted.

Does a chimney cap Reduce draft?

A well chosen chimney cap will not adversely affect your chimney's draft, and it might even improve it. ... If you do not keep the screens clean and clear, they can reduce your chimney's draft, resulting in a dirtier chimney and in smoke backing up into your house.

Is my fireplace opening too big?

An ideal fireplace opening would be no more than ten times the cross sectional area of the chimney flue. For example if the inside dimensions of the flue are 10 x 10 equalling 100 square inches, then the fireplace opening should not exceed 10 times this or 1000 square inches.

Do chimney fans work?

Chimney fans work by employing mechanical venting to overcome fireplace and chimney gravity drafting deficits. ... Exhaust gases from the wood or gas fireplace rush into that vacuum and flow up the chimney and out the sides of the vents in the fan.

How tall should a wood burner chimney be?

Chimney Heights and Termination

The minimum chimney height recommended for minimum performance of wood burning and multi fuel appliances is 4.5 m from the top of the appliance to the top of the chimney. It is best to position the chimney, so that it goes straight up as near to the roof ridge as possible.

Does removing a chimney breast devalue a house?

Does removing a chimney breast devalue a house? The answer to this question depends on what type of house you have and its method of heating. ... Depending on the size of the rooms, hearths and chimney breasts, you might gain a small amount of extra space in each room.

How far does a chimney have to be from a wall?

STOVEPIPE PROTECTION: Stovepipe, and chimney connectors, must also be a certain distance from both combustible walls and ceilings. The NFPA calls for an 18" clearance to combustible walls for single wall stove pipe. Double wall stovepipe is used when you don't have 18" or more clearance from combustibles.

How high should a chimney be above the roof?

The chimney opening above the roof of a sticks and bricks house should be 3 feet above the roof line, or 2 feet above any part of the building within 10', whichever is higher. For most small structures like small cabins and tiny homes, the tallest part of the structure is within 10' of the chimney.