Frequently Asked Questions about the Wildland Urban Interface

Establishment of the Wildland Urban Interface

Teton County is known for expansive vistas and large swaths of forested lands managed by private and public entities. Fires has historically been a natural part of the environment. As the valley watched the 1988 Yellowstone Fires many realized if it could happen there, it could happen here. A group of fire managers began work to study fire on the landscape; mapping the interface between forest areas and homes referred to as the wildland urban interface (WUI), forming the Teton Area Wildfire Protection Coalition (TAWPC), and writing a community wildfire protection plan (CWPP).

As new construction pushed into the interface areas, codes pertaining to fire resistant construction within these higher hazard fire areas would help prevent structure loss in the event of future fire. These codes were adopted in 2008 with the ability to adjust the ignition resistance of the structure in relation to the fire severity of the area.

Common Questions:

• Do all structures in the WUI need a review?  No. There is some work exempt from permitting.  One-story detached accessory structures used as tool and storage sheds, playhouses and similar uses, provided the floor area does not exceed 120 square feet and the structure is located more than 50 feet from the nearest adjacent structure.   Projects that are strictly interior and do not impact exterior components, including windows, doors, and decking, are also exempt.  Re-Roofs and interior only projects do not require a WUI memo.  Please call our office  prior to submittal if it is unclear for your project. 
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• How do I determine how much defensible space I can provide?  Defensible space is measured from the closest perimeter or projection of your structure to the lot lines or property boundary.  Additionally, the space between structures is also used in the determination.  The minimum amount of defensible space permitted by the IWUIC is 30 feet. If a new project cannot meet 30 feet of defensible space, increased ignition resistant construction shall be required. 
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• What kind of trees may I plant in the WUI? Deciduous trees are the best choice for the WUI. Per the IWUIC all trees must be planted 10 feet from the structure and 10 feet from each other.  Jackson Hole Fire/EMS will allow deciduous plantings to be closer to one another and closer to the structure as long as they are not hanging over the roofs.   Coniferous trees carry a heavy fuel load that only grows as the tree does, they MUST follow the conditions of the code. Although not required at the time of WUI application, we strongly recommend discussing your landscape plan with the fire department prior to building final.  A structure may not receive final sign off from this department if the vegetation requirements are not met.  
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• Will the fire department require me to remove my existing trees?   Only in the event of new construction.  If an addition or alteration is being made to a house, that property may have to remove or relocate plant materials.  If there is no new construction, the Fire Department does not have any requirements.  We do provide voluntary, non-binding, site visits to inform building owners about best practices.  Please all 307-733-4732 to make a request. 
• Diagram of defensible space:

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• What is your recommended roofing material?    Long lasting, weatherproof material that resists fire. Fire-treated wood shake roofs do not retain their fire resistance long in this climate due to UV light, snow loads, and other environmental conditions.  Effective January 01, 2025  Wood shakes and shingles are no longer allowable for any project in Teton County.  
• Synthetic Shakes are a common alternative for homeowners trying to achieve the same appearance as real wood shakes  There are many products available with varying degrees of fire resistance.  Roof products with code evaluation reports indicating a Class A rating, written by qualified testing agencies,  will be approved by this department when installed according to manufacturer’s requirements.
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• How do I determine if the material I want to use meets the ignition resistant requirements? The best place to begin is to look at your product's specification sheets. The IWUIC outlines which ASTM, UL, etc. listings need to be met for materials used to meet Ignition resistant construction.  You can also call the product manufacturer.   A quick reference is the California State Fire Marshal’s page which has an abundance information.  In general, if the California State Fire Marshal will allow a material, Teton County will as well.  Any products that requires a “fire rated assembly” should be directed to the appropriate building official. 
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• Under what conditions may I have a cold roof?  A cold roof is a roof assembly constructed with a ventilated cavity above the insulated roof to equalize exterior and interior temperatures through the process of air movement. Cold roofs are allowable when fire/ember resistant vent guards that comply with the requirements of the current version of the IWUIC are used.