Isokern Chimney Offset Blocks


Isokern Offset Blocks offer the ability to move a vertical chimney from side to side, allowing it to pass objects above the firebox. Many current architectural specifications require a diverse chimney system to allow for more custom applications. The offset block is used to create a 3-inch horizontal offset for each 5-inch of vertical rise.




Modular refractory masonry precast chimney components.

Designed for field assembly as a chimney unit.

All interlocking parts necessary for assembly of a complete Class “A” masonry chimney unit.

Interlocking double module chimney components.


Light weight concrete of a proprietary mixture of Icelandic volcanic aggregate and aluminum cement for precast chimney block and flue liner components.

Compressive Strength: Chimney Block: 972 psi.

Compressive Strength: Flue Liner: 1175 psi.


Tensile strength: 807 psi; Compressive strength: 2460 psi.

Tested per ASTM C109, ASTM C307, and ANSI 118.4.


Reference manufacturer’s installation instructions for standard configurations, weights, sizes and installation details.

Chimneys to be assembled on site oer manufacturer’s illustrated instructions.

Premixed EARTHCORE ADHESIVE is used at all joints between components.

Firebox to be lined with a minimum 1 1/8” rated firebrick.

Chimney system listed for “Zero Clearance” ti uninsulated wood framing members.


Warnock Hersey/Intertek Testing Services Report No. 632-912500

Meets or exceeds UL 103HT; UL 1777; ULC 5610


ICC NO. ESR 5017 / LARR#2823

We have owned an Isokern Fireplace in our home for over 9 years now. We like the Isokern pre-engineered firebox produces a consistent fire draw. In the past we had experienced some poor draws in our existing fireplaces and wanted a better fire experience. We also liked that the interior firebrick could be customized to give you various looks for the fireplace. We would definitely consider another Isokern Fireplace for our outside porch.

Barbara and Bob Dougherty

We have been working with Earthcore for many years. On the product end, the Isokern Masonry products they manufacture are second to none. The precision in which they build their components is unlike anything we have ever tried.

On the business end, we love the staff at Earthcore! From the employees I met at their factory, to the owner of the company I had the pleasure of meeting at a trade show in Nashville, TN……this company is a great organization that I look forward to growing with for many years to come.

Hill Dickerson
Dickerson Hearth Products

I’ve been woking with Earthcore for years. Claudia has been very helpful making things go smoothly out in the field and in helping with choosing the right fireplace to achieve the best looks. I have had great feedback from past customers on the product and plan on continuing to use these fireplace units.

Bruce Winfrey
Winfrey Design Build

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