Gas Fireplace Hearth Requirements

Gas Fireplace Hearth Requirements (With Real Examples)

In Gas Fireplaces by James O'Kelly1 Comment

Although gas fireplaces don’t burn solid fuel like many other types of fireplace, gas fireplaces still do use a real fire to burn gas and generate heat.

Certain safety measures therefore still need to be met in order for a gas fireplace to be operated safely; one of which can be a platform of non-combustible material out the front and sides of the fireplace known as the hearth.

However, there are a number of different types of gas fireplace and the same safely measures that applies to one may not apply to others, so which gas fireplaces need a hearth?

The requirements for a hearth for a gas fireplace will typically come down to what is required by the manufacturer for that particular model of gas fireplace. However, natural vent gas fireplaces often require a hearth while direct vent and ventless versions may not, depending on the manufacturer requirements and local building codes and regulations.

Our own gas fireplace is a natural vent gas fireplace insert and a hearth of sufficient depth and size is required as per the manufacturer’s instructions.

We’ve covered the requirements for gas fireplace hearths in more details below, explaining what exactly was required for our own gas fireplace.

For more information on fireplace hearths in general, including what they are, what they do and what they’re made of see our complete guide to fireplace hearths.

Do Gas Fireplaces Need A Hearth?

Hearths are the platform on which fireplaces are placed to help protect the floor of a home.

The word hearth can define the platform on which a gas fireplace sits.

Hearth extension can mean the area that the hearth extends to out the front and sides of the gas fireplace.

A gas fireplace may have requirements for both the hearth on which it sits (such as thickness) and the heath extension that protrudes out the front (such as minimum coverage area).

Natural Vent Gas Fireplace With Chimney
Our gas fireplace and its associated hearth

Whether a gas fireplace needs a hearth can typically come down to:

  • The type of fireplace, such as natural vent, direct vent, ventless and zero-clearance.
  • The requirements set by the manufacturer within the instruction manual for a particular model of gas fireplace.
  • Local and/or national building codes/regulations.

When it comes to finding out the hearth requirements for your own particular situation, the below steps should be followed:

  1. See what the hearth requirements are for a particular model of fireplace, either by reading the instruction manual or speaking to the seller.
  2. Discuss the code and regulation requirements for gas fireplaces and hearths with a local installer for your particular area of residence.

The requirements of a hearth or hearth extension for each type of gas fireplace or gas fireplaces in general can differ depending on your area of residence.

Always consult a local installer for advice and guidance on the codes and regulations for gas fireplace hearth requirements near you.

Gas Fireplace Types

The type of gas fireplace can largely impact whether a gas fireplace needs a hearth, hearth extension and the requirements of that hearth.

The main types of gas fireplace include:

  • Natural Vent
  • Direct Vent
  • Ventless

Natural Vent Gas Fireplace Hearth Requirements

Natural vent gas fireplaces, often also referred to as B-vent, are the more traditional form of gas fireplace.

They can commonly be found as inserts for installation into existing masonry fireplaces but may also be standalone units that need to be vented through the roof with a pipe.

Natural vent gas fireplace inserts will typically have an open front so that the fireplace can use the air within the room and vent it up through the chimney.

An open front means that natural vent gas fireplace inserts typically require a more suitably sized hearth for safety reasons.

Our own gas fireplace is a natural vent insert.

Gas Fireplace

It was already installed in the living room fireplace when the house was bought. It sits on a suitable hearth that meets the requirements outlined from the manufacturer for this particular model of gas fireplace insert.

Gas Fireplace Hearth

The manual for our gas fireplace explains that in terms of the requirements of a hearth:

The appliance is designed for installation on to a non-combustible hearth of at least 300mm depth and of at least 12mm thick.

The hearth must extend a minimum of 150mm either side of the opening and a minimum of 300mm in front of the opening. The hearth must also be a minimum of 50mm in height or be surrounded by 50mm high fender.

No combustible material should protrude onto the hearth.’

Focal Point Fires

These are the hearth requirements for our own particular model of gas fireplace, and in line with regulations for where we live.

See the instruction manual for your own particular version of gas fireplace for more information on the hearth requirements.

Direct Vent Gas Fireplace Hearth Requirements

Direct vent gas fireplaces can come under the category of built-in gas fireplaces and differ to natural vent gas fireplaces in that both waste and clean air is vented externally.

This means that the air inside a direct vent gas fireplace doesn’t mix with the air inside a home and don’t need to be installed in existing masonry fireplaces like natural vent insert models.

A direct vent gas fireplace can therefore have less onerous hearth requirements because they will have a glass front.

Direct Vent Gas Fireplace
A direct vent gas fireplace may or may not need a hearth

A direct vent gas fireplace may not require any form of fireplace extension at all.

Again, the specific hearth requirements will come down to the model of direct vent gas fireplace.

We don’t personally own a direct vent gas fireplace but by inspecting the owners manual of this randomly selected model of direct vent gas fireplace shown here highlights the hearth requirements.

A hearth extension is not required with this fireplace. If a hearth extension is used, do not block access to the control compartment. Any hearth extension is used for appearance only and does not have to conform to standard hearth extension installation requirements.’

Innovative Hearth Products

It may therefore be possible to still use a hearth extension with a direct vent gas fireplace for looks purposes rather than functionality, if conforming with the fireplace’s requirements.

This gas fireplace is also zero clearance meaning that it may not require a hearth on which to sit on (separate to the hearth extension).

The fireplace is approved with zero clearance to combustible materials on all sides (with an exception).

Innovative Hearth Products

It can be common for many other forms of direct vent gas fireplace to also not require any form of hearth or hearth extension, but always read the instruction manual and speak to an installer or seller if unsure.

Ventless Gas Fireplace Hearth Requirements

Ventless gas fireplaces differ from the other types in that they don’t vent externally.

Ventless Gas Fireplace
A ventless gas fireplace may also not require a hearth

However, ventless gas fireplaces may follow similar hearth requirements to direct vent gas fireplaces in that a hearth extension may not be required.

Depending on the model of ventless gas fireplace and whether it’s zero-clearance rated it may also not need to sit on a non-combustible platform.

However, as always check the instructions for your chosen model of ventless gas fireplace for more information.

Further Reading

What Gas Fireplaces Look Like

What’s Inside A Gas Fireplace

How To Know If You Have A Gas Fireplace

Do Gas Fireplaces Need A Chimney?


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