A flange extension allows you to extend the mounting point of your fire pit valve through thicker stone, block, or paver enclosures. This makes it easier to install your valve flange flush with the outside of your fire pit while keeping the shut off valve properly positioned inside the enclosure.
When building a custom gas fire pit, enclosure wall thickness can create challenges for installing a standard shut-off valve and flange. A flange extension solves this problem by extending the valve assembly outward so you can maintain clean access to the valve key and preserve a finished, professional appearance.
This guide explains what a flange extension is, when you may need one, and how to properly use it in your gas fire pit project.
What Is a Flange Extension?
A flange extension is a threaded fitting used to extend the mounting point of a fire pit valve flange farther away from the shut off valve itself. This becomes especially useful when building a fire pit enclosure with thicker stone, brick, pavers, or concrete block.
Without a flange extension, the valve flange may sit recessed too deeply inside the enclosure wall, making it difficult to insert or operate the valve key properly. A flange extension helps bring the flange flush with the outside surface of the enclosure for easier access and a cleaner installation.
When Would You Need a Flange Extension?
Flange extensions are commonly used in custom fire pit builds where enclosure materials are thicker than a standard valve assembly can accommodate.
Common Applications Include:
- Stone veneer fire pit enclosures
- Concrete block fire pits
- Paver stone installations
- Brick fire pit surrounds
- Custom masonry projects
- Recessed valve installations
If the enclosure wall prevents the flange from sitting properly on the exterior surface, a flange extension is usually the easiest solution.
Parts Needed for a Flange Extension Installation
Before installation, make sure you have the following components:
- Gas shut off valve
- Valve flange
- Flange extension
- Coupler
- Valve key
- Proper drill or core bit for the enclosure material
You may also need a longer valve key depending on the final extension depth.
How a Standard Fire Pit Valve Works
A Standard Shut Off Valve & Flange
A standard fire pit shut off valve features three primary connection points:
- The gas inlet
- The gas outlet
- A 3/4-inch male threaded fitting where the flange normally attaches
In a typical installation, the flange threads directly onto the valve assembly and mounts against the outside wall of the enclosure.
How to Install a Flange Extension
Using a Flange Extension
Instead of threading the flange directly onto the shut off valve, the flange extension is installed between the valve and flange to move the mounting point outward.
The installation sequence typically works like this:
- Attach a 3/4-inch coupler to the shut off valve fitting.
- Thread the flange extension into the coupler.
- Thread the flange onto the opposite end of the extension.
- Mount the flange flush against the exterior wall of the enclosure.
This setup allows the valve to remain safely positioned inside the enclosure while extending the flange outward for easy access.
Sizing a Flange Extension for Stone or Block
The Extension Installed in a Paver Stone
Many flange extensions are designed around common enclosure wall thicknesses. In this example, the extension is 6 inches long to accommodate standard paver stones that typically measure between 7 and 8 inches thick when combined with the valve fitting, coupler, and flange assembly.
For this particular installation, a 1 3/8-inch hole was cored through the enclosure material to accommodate the fittings.
Before drilling or coring through stone or block, always verify the required clearance for your specific valve and extension components.
Custom Sizing a Flange Extension
Adjusting Extension Length
Every fire pit enclosure is different, so flange extensions sometimes need to be adjusted to match the exact wall thickness.
Depending on your project, you may be able to:
- Use multiple flange extensions together
- Trim an extension to a shorter custom length
- Adjust fitting depth slightly during installation
It’s important to note that the flange extension assembly itself is not part of the pressurized gas path. The extension primarily acts as a mounting and alignment component for the flange and key access. Even so, all gas components should still be installed carefully and inspected by a qualified professional when necessary.
Choosing the Correct Valve Key Length
Longer Keys for Extended Flanges
Once the flange extension is installed, you’ll need a valve key long enough to comfortably reach the shut off valve inside the enclosure.
Longer valve keys are often required for thicker fire pit walls or deeper installations. Choosing the correct key length ensures smooth valve operation and easier access when turning the gas supply on or off.
If you're unsure which valve key length is compatible with your setup, our product specialists can help you choose the correct configuration.
Frequently Asked Questions
Can you cut a flange extension?
Yes. Depending on the material and design, some flange extensions can be trimmed to fit custom enclosure depths.
Can multiple flange extensions be combined?
Yes. In some installations, multiple extensions can be connected together to accommodate thicker enclosure walls.
Do flange extensions carry gas?
The flange extension primarily functions as a mounting and access extension rather than part of the active gas flow path, but all components should still be installed properly and inspected when necessary.
What size hole is needed for a flange extension?
The required hole size depends on the valve and fitting dimensions, but many installations use approximately a 1 3/8-inch opening.
Final Thoughts
Flange extensions are a simple but extremely useful solution for custom gas fire pit projects with thicker stone, brick, or paver enclosures. By extending the flange outward from the shut off valve, you can maintain clean valve access while preserving the appearance and functionality of your fire pit installation.
If you need help choosing compatible fire pit accessories, shut off valves, flange extensions, or valve keys, contact our product specialists for expert guidance.
