07 January 2011

Newsflash: Strawbale MEETS Current Building Codes

This post is based on an article first published in the June 2006 issue of The Last Straw Journal and is also posted at www.buildnaturally.com

There seems to be a broad misconception that strawbale construction requires a fight with the local building permit office.  This is simply not true, and a fighting attitude will probably end up being counterproductive.  Instead, I advocate 3 simple steps to building permit success for your strawbale structure:  1) be informed, 2) get support, and then 3) collaborate with permit officials.  The bottom line is that non-structural applications of natural building materials, including strawbales, are in compliance with current building codes.  Structural applications generally require some additional support from a structural engineer.
Strawbale infill walls MEET codes
Rubble trench footers MEET most codes
THE FACTS:
  1. The intent of ALL U.S. building codes is to ensure health, safety, and, to some degree, durability.  Likely you have the same goal for your natural building project, so you are in alignment with the goals of the building codes.
  2.  The role of permit officials is supporting you to ensure #1 above.  If you are open & collaborative, permit officials will generally collaborate with you to help you achieve your building goals.
  3. U.S. building codes do NOT exclude alternative materials or techniques.  Rather, each code begins with a caveat that allows for anything not specifically listed in the code to be approved as long as you show that it meets the INTENT of the code for durability, effectiveness, and safety (including fire resistance).
  4. Demonstrating compliance with the building codes is possible thanks to many pioneers that have dedicated time & money to sponsor third-party ASTM (American Society for Testing and Materials) tests.  The results of these tests demonstrate that strawbale wall systems not only meet the building code, but in most cases surpass the intent of the code compared to standard stud-and-drywall construction.

How to use these facts to your advantage: 3 STEPS TO PERMIT SUCCESS!
I have used the following approach with a 100% success rate to obtain standard building permits for over 20 natural building projects, many of which were the first alternative structure in their jurisdiction.

STEP 1:  BE INFORMED
...on what you are building
Be familiar with your drawings and fully understand your natural building material of choice, whether strawbale, cordwood, cob, or whatever.  Understand how it is installed, what the physical properties are, and what the pros & cons are.  You will likely have the pro list at the tip of your fingers, since this is the material you chose.  However, I also recommend understanding the limitations of your material of choice so that you can address any questions that come up in a realistic and honest manner. 

...on your building codes
Confirm if your code jurisdiction has any building codes for natural building materials or methods.  If yes, then make sure your proposed plans are in compliance with that code.  If there are no existing codes, then find out which code is used.  Find a copy of that code (I recommend the library, since code books are expensive) and write down each section that is effected by your material choice.  For example, with strawbale walls, you will look for any code language that defines the performance of exterior walls (insulation, fire rating, etc.)  Then you simply need support information that describes how your material meets the INTENT of that code section.  For some items this is common sense...the fire rating for cob is a non-issue, since cob is non-flammable.   For some items, like demonstrating the insulating value of a strawbale wall, you will need that third-party data available from natural building pioneers.  Many of these tests are available for free online.  See www.dcat.net/resources and scroll all the way to the bottom of the page.  And remember, the question is not whether you can get a building permit, but rather, how to best communicate with local building officials that your natural building material is a viable, durable choice that meets the existing building code.

STEP 2:  GET SUPPORT

I find it is extremely helpful to have someone on your team that has experience with whatever natural building material you are using.  This can be whoever designs or drafts your building, it can be a structural engineer, or it can simply be a natural builder in your area that you hire as a consultant.  This gives you someone you can ask questions of, as well as a resource for the permit office with any of their questions.  A building official will generally have more confidence in your project when they know someone on your team fully understands and has experience with your alternative building material.


STEP 3:  COLLABORATE WITH PERMIT OFFICIALS
Here I recommend scheduling a pre-submittal meeting with the permitting official to communicate your intentions to build with an alternative material.  This meeting gives you the opportunity to describe the merits of your material, and gives the permit officials the opportunity to pose any questions they might have.  They can educate you on process and performance requirements.  You can educate them on your natural building material of choice.  I recommend bringing some printed information with you, perhaps a book with photos of similar buildings, any code research you've done, etc.  But try to keep the information to a reasonable quantity so it's not overwhelming.  You can always send along additional information if requested.

What I bring to the pre-submittal meeting:
  • drawings of the proposed building
  • an brief overview of strawbale construction (I use “House of Straw – Strawbale Construction Comes of Age” by the US Dept. of Energy, available from www.grisb.org/publications/pub23.pdf), or cordwood, or whatever you are building with 
  • some photos of similar buildings (from the internet or a book)
  • copies of related ASTM testing data (fire-related ASTM tests are at www.dcat.net/resources at the bottom of the page)
At a minimum, be prepared for the following common questions:
  • How does your wall system handle liquid water and vapor?
  • What is the fire rating & smoke development rating of the wall system?
  • Will the wall system attract pests, such as termites or rodents?
  • What is the insulating value of the wall system?
  • How is electrical and plumbing installed?

During the meeting, don't be afraid to admit you do not know something.  I find it's more productive to say you will find the information and follow-up to get it to them, then it is to disseminate incorrect information.  And don't be afraid to ask them to help you!  Ask specifically what they would need to have...drawings, information, stamps from a professional, etc...in order to approve your project for permit.  Remember that your building official is your ally not your adversary, and has the same goal as you: to ensure that what gets built is safe.  Acknowledge your common interest for occupant wellbeing and safety.  You will create connection instead of confrontation and open a dialog on how to achieve your common goal.

For the final permit submittal, my experience is that stamped structural drawings greatly facilitate the speed and ease of the permitting process, so I use a structural engineer on every project.


MY EXPERIENCE
I have to date not experienced any delays during the permitting process using this method of interaction with building officials.  Increasingly, I find that building officials already possess some level of knowledge about natural building materials, especially strawbale construction.  This was not the case on the East Coast of the U.S. even 5 years ago.  In most cases, interacting with permit officials brought them fully on board and garnered curiosity in other natural building materials & methods.

FINAL NOTE
Finally, I would like to address the issue of adopting existing codes and details in different climates.  I design structures in a wet, humid climate with hot summers and cold winters.  However, many of the now-standard strawbale details have mostly developed in arid and temperate climates that are not necessarily durable in this mixed climate.  For example, I do not recommend using rebar inside a strawbale wall in a humid climate, since the cold metal creates an artificial dew point inside the straw wall.  The result is elevated moisture around the rebar, which can lead to rotting the straw over time.  Instead, I recommend external pinning or using materials that are “warm”, such as bamboo.  Similarly, pea gravel at the base creates an artificial dew point, as well as creating a thermal break along the entire base of the wall.  My point is not that the originally developed details are inadequate, but rather that they are specific to an arid climate.  So when adopting codes and details in different regions with different climatic concerns, ensure that what you propose will perform durably in your climate.


RESOURCES
I think these two books are the best resources to learn about how to build with strawbales in wet climates.  All of the authors live in snowy, wet, humid climates.

         
click the book covers above for more info or to purchase

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