The Wildland Urban Interface and our Local Construction Guides
For better or worse, we have all become a little more conscious of our built environment's proximity to wildfire-prone areas over the last couple years, and 2018 especially. For those in the construction industry, and those learning hands-on while rebuilding, the term "WUI' or "Wildland Urban Interface" is thrown around quite a bit. To break down that jargon barrier, I thought I'd share a little background on the technical requirements that go along with homes and other structures that are mapped as being within a Wildland Urban Interface. The WUI is also referred to, sometimes interchangeably, as the 'Very High Fire Hazard Severity Zone" by Cal Fire and it exists both within the State Responsibility Area or SRA (where Cal Fire responds to calls first) and the Local Responsibility Area or LRA (Where City of Redding responds to calls first). Basically, it doesn't matter whether you live in the City proper, or out in the County, it is equally possible for a property to be in a WUI, it will just determine which map you need to look at. The SRA WUI map can be found here and the LRA WUI map (proposed by Cal Fire and adopted by the City of Redding) can be found as a layer in the City of Redding Interactive Map View, found here. Although it is important to note that the 'Very High Fire Severity Zone' layer is located under the 'Crime Map (Public Safety)' drop down, don't ask me why.
Just a little background information to put you to sleep, Chapter 7A - Materials and Construction Methods for Exterior Wildfire Exposure was introduced to the California Building Code (CBC) in the January 2009 supplement, and has been Chapter 7A in each subsequent code cycle (2010, 2013, 2016). If you would like to review the complete code chapter for yourself, here is a link to an online reader set to that chapter. The same information can also be found in the California Fire Code - Chapter 47 and in the California Residential Code (each are a component of the California Building Standards Commission, also known as Title 24 of the California Code of Regulations).
The City of Redding took significant strides back in 2008 to implement and publicize the WUI-related Chapter 7A code changes into their city standards, as evidenced by their Fire Safe Building Construction & Methods Guide published in 2008 (Link here). This document is based loosely on FEMA's Home Builder's Guide to Construction in Wildfire Zones (Link here), which was also published in 2008. The problem however, is that neither of these documents has since been updated where the California Building Code has been further developed with each code cycle (every 3 years) over the last 11 years. Today's current code - the 2016 CBC - includes a number of revisions or updates to the original code that have not been adopted into our local review and inspection protocols, even though architects, residential designers and contractors are held to the higher standard of the CBC. A few notable upgrades being the restriction in size of ventilation perforations being decreased from 1/4" to 1/8" and the requirement for all soffit/eave vents to comply to a stringent ember-resistant testing standard - one that only (3) companies to date have been certified as compliant by the State Fire Marshal.
We have seen our local officials engaging in community planning sessions, and working on plans to be more resilient for the next big disaster, however, all of the re-build permits that have been or are in the process of being pulled are being held to the same deficient 2008 standards. For architects who follow the code changes and incorporate these into their plans, the risk is minimal. However, for residential designers and contractors who just submit the City of Redding approved details (found in the 2008 guide), the deficiencies are being perpetuated. Unsurprisingly, the higher standard of construction required by the 2016 codes brings with it a cost increase - one that some contractors and homeowners will be tempted to forego if they know the city won't be enforcing it, despite the increased risk to losing their home once again.
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Please note that the opinions in this article represent those of the author and not the Envision Redding group as a whole.
