Excerpted from YURTS: Living in the Round, pp. 96-97 and Apendix I.
One of the most complicated issues people face in using yurts as either a home or workspace involves the building permit process. Code requirements vary from state to state and within counties and local communities. Individual officials, even within the same locale, may interpret the rules differently. Add to this the fact that many code officials have little or no experience with yurts, and the situation can become very confusing.
Before you buy a yurt, it’s a good idea to check with your local Building Department to see what the rules are in your area and how local officials are likely to respond to your particular yurt application. (The building department may be contained within your local Planning Department, or it may be connected to another office like the Fire Dept.) You also may need to check with your local Health Department regarding septic or sewer issues.
Here are some questions to ask your local officials:
- Which set of code regulations is the department using? Are they using the 2003 or 2006 ICC (International Code Council) codes, or are they still using the UBC (Uniform Building Code)? The two ICC rulebooks are: the residential IRC (International Residential Code) and the commercial IBC (International Building Code). The IBC is more comprehensive than the IRC and supersedes the IRC in the case of conflict.
- What are the local planning regulations (these vary per jurisdiction).
- What are the specific local requirements for snow load, seismic rating, and wind speed? Are there any other special requirements?
- What are the fire-rating requirements (for the insulation and outer fabric)?
- Has the department previously approved yurts in this city or county? If so, which manufacturers have been approved?
- If the building department hasn’t previously worked with yurts (or with your prospective company), is there a licensed engineer to whom your company can send engineering specs for review?
- Would it be helpful to have contact information for building officials in other places where yurts have been approved?
Here are some things to keep in mind as you go through the permitting process:
As a membrane structure, yurts are usually classified in the “alternative structures” category, which has a unique set of code regulations. (See “Building Code Excerpts” section below.)
If your yurt is classified as a permanent or long-term alternative structure, it will have to meet local requirements for snow load, wind speed, and seismic ratings. You will also have to show that the yurt materials are fire retardant. If your yurt is being set up as temporary structure, for six months or less, the requirements are much more flexible.
Local stipulations vary. For example, a town might have a snow-load requirement of twenty-five pounds per square foot, and the nearby ski resort could have a requirement of one hundred pounds per square foot. When you talk with your yurt company, you might find that their standard snow and wind kit would work for the in-town requirement, and that for the ski resort you would need to purchase a yurt that had been specifically engineered for heavier snow loads.
If your yurt will be used for residential purposes, it will also have to meet local regulations for residences (like heat source, size and type of openings, egress windows in sleeping areas, and so on). If you are using the yurt for commercial purposes, you’ll have to meet an additional set of commercial regulations.
Here’s how your yurt company can help:
- You can use the promotional materials provided by the company to show your code official what it is you are planning to “build.” You might also take in the book YURTS: Living in the Round, and let the building official leaf through it to get a better understanding of what yurts are and how they are used.
- The company may be able to supply engineering specs, if necessary, to a local engineer certified by your state who can sign off the plans for the local building department. The engineering specifications must relate to the strength and stability of the yurt as a complete assembly, not just the component parts (like rafters).
- The company can give you contact information for other code officials who have approved their yurts and can advise your local building department.
- The company can give you the specific information about your yurt that you need for your locale regarding snow loads, wind specs, seismic rating, fire retardance and insulation.
Yurts and the Energy Code
The biggest code challenge for yurts is insulation. Building codes rate insulation by R-Value alone. R-Value (resistance to conductive heat transfer) analyzes only conductive-type insulation like fiberglass; there are no guidelines in the codes for reflective insulation.
Reflective insulation will work only while your heat source is operating (reflective insulation reflects heat back into the space; it will not hold the heat in once the heat source goes out). However, while your heat source is operating reflective insulation is much more effective than conductive insulation.
Conductive-type insulation is up to 95 percent effective for reducing conductive heat loss; however, over 75 percent of heat loss is radiant. Reflective insulation reduces radiant heat loss by as much as 97 percent (conductive-type insulation reduces it by only by 5 to 10 percent). One test showed reflective insulation to be more than seven times as effective as R-19 conductive insulation.
Yurtco Manufacturing states it this way on their website:
It is a common misconception that insulation must be thick to perform well. It is also a common mistake to consider only a material’s R-Value when choosing insulation. It is highly possible for a thinner reflective material to provide better thermal performance than a thicker non-reflective product.
For the purposes of current building codes, reflective insulation does not exist. The type of insulation typically used in yurts can be rated only in conductive terms, which in the case of a layer or two of bubble wrap (the conductive element) provides a relatively low rating.
Your code official may understand the efficacy of your reflective insulation and be willing to figure in other factors, like your heat source.
It may be possible to get an exemption if you are incorporating a renewable heat source. Pellet stoves are an example of a heating method that utilizes a renewable resource (the pellets are made from agricultural waste products). Other examples are wood stoves using dead or thinned trees and electric heaters run with power generated by wind or water. People have been exempted when generating their own power to run heaters.
There is also the possibility of greater code flexibility if the yurt is not being heated continuously (such as when occupancy is “transient and intermittent,” as with camping rentals or a vacation retreat).
If, however, your building official feels compelled to stay within code parameters and you are planning a permanent residence, it may be difficult to get a portable fabric yurt approved. One final option is to provide your code official with the contact information for other building officials who have yurt experience and can point out ways to get around the apparent difficulties.
If yurts have been approved for resorts and parks from South Carolina to Alaska, and for uses as diverse as schools and offices as well as residences, a well engineered yurt should have strong potential for approval in most locales.
Building Code Excerpts
Some states use the UBC (Uniform Building Code), but many states, provinces and countries currently use the ICC (International Code Council) code books, which consist of the commercial International Building Code (IBC)and the International Residential Code (IRC). There are also sub-codes, such as the International Energy Conservation Code, which add to and modify the general code books.
These excerpted sections are drawn from the 2003 IBC (commercial code). Section 104 on the duties of building officials is the same in the commercial and residential codes; Section 3102 on Membrane Structures exists only in the commercial code; it defines the category for the residential code as well. The building code terminology for the fabric yurt is “membrane covered frame structure.”
As was stated above, in order to be permitted a yurt may have to meet requirements in the areas of snow load, seismic rating, wind speed and fire safety, but these are dependent on location and the information has to come from the local code official. Other requirements like egress and occupancy are dependent on the use of the yurt (e.g., residential or commercial).
2003 INTERNATIONAL BUILDING CODE
SECTION 104: DUTIES AND POWERS OF BUILDING OFFICIAL
104.10 Modifications. Wherever there are practical difficulties involved in carrying out the provisions of this code, the building official shall have the authority to grant modifications for individual cases, upon application of the owner or owner’s representative, provided the building official shall first find that special individual reason makes the strict letter of this code impractical and the modification is in compliance with the intent and purpose of this code and that such modification does not lessen health, accessibility, life and fire safety, or structural requirements. The details of action granting modifications shall be recorded and entered in the files of the department of building safety.
104.11 Alternative materials, design and methods of construction and equipment.
The provisions of this code are not intended to prevent the installation of any material or to prohibit any design or method of construction not specifically prescribed by this code, provided that any such alternative has been approved. An alternative material, design or method of construction shall be approved where the building official finds that the proposed design is satisfactory and complies with the intent of the provisions of this code, and that the material, method or work offered is, for the purpose intended, at least the equivalent of that prescribed in this code in quality, strength, effectiveness, fire resistance, durability and safety.
SECTION 3102
MEMBRANE STRUCTURES
3102.1 General. The provisions of this section shall apply to air-supported, air-inflated, membrane-covered cable and membrane-covered frame structures, collectively known as membrane structures, erected for a period of 180 days or longer. Those erected for a shorter period of time shall comply with the International Fire Code.
3102.2 Definitions. The following words and terms shall, for the purposed of this section and as used elsewhere in this code, have the meanings shown herein:
MEMBRANE-COVERED FRAME STRUCTURE. A nonpressurized building wherein the structure is composed of a rigid framework to support a tensioned membrane which provides the weather barrier.
3102.7 Engineering design. The structure shall be designed and constructed to sustain dead loads; loads due to tension or inflation; live loads including wind, snow or flood and seismic loads.
2003 INTERNATIONAL ENERGY CONSERVATION CODE
101.3 Intent. The provisions of this code shall regulate the design of building envelopes for adequate thermal resistance and low air leakage. It is intended that these provisions provide flexibility to permit the use of innovative approaches and techniques to achieve effective utilization of energy.
103.1 General. The provisions of this code are not intended to prevent the use of any material, method of construction, design or insulating system not specifically prescribed herein, provided that such construction, design or insulating system has been approved by the code official as meeting the intent of the code.
For further reading on codes and appropriate techonolgy, see this excellent article by David Eisenberg.