Coming Soon: Building Code Standards for SIPs

Coming Soon: Building Code Prescriptive Standard for SIP Construction
by Ted Cushman


The Partnership for Advancing Technology in Housing (PATH) program of the U.S. Department of Housing and Urban Development (HUD) website: (www.pathnet.org) has launched an initiative to standardize structural insulated panel (SIP) construction methods and include SIP techniques within the main body of the International Code Council’s model building codes. The 12-month push will be managed by the NAHB Research Center website: (www.nahbrc.org), in close cooperation with the Structural Insulated Panel Association (SIPA) website: (www.sips.org).

“We’re trying to level the playing field between alternative methods and wood construction,” said Nader Elhajj, the NAHB Research Center’s Director for Alternative Materials. Elhajj, who recently succeeded in similar efforts to create prescriptive code standards for steel framing and for insulated concrete forms, is already assembling a “steering committee” for the SIPs project that will include representatives of the panel manufacturing industry, design professionals, builders, code officials, and academic experts. Once the standard is complete, SIPA, PATH, and NAHB Research will propose the method for adoption as a dedicated SIP construction chapter within the International Building Code and International Residential Code.

The International Codes are adopted as official building standards by most states and municipalities in the United States; writing advanced SIP methods into the body of the model codes will remove the current time-consuming and costly requirement for SIP home projects to get case-by-case approval from local building officials as an “alternate method” under the code. The Prescriptive Method for SIP Construction will be inclusive enough to encompass the most popular techniques currently employed by SIP suppliers and builders around the nation; however, methods not included in the prescriptive code will still be able to gain individual approval, either by documenting equivalent or better performance to the satisfaction of building officials, or as part of a design analyzed and sealed by a licensed design professional (architect or structural engineer).

For the benefit of SIPA membership and the public, the following answers to commonly asked questions have been provided by Dana Bres, P.E., a Research Engineer with HUD's Office of Policy Development and Research and a director of the PATH program; by Nader Elhajj, P.E., director of the Alternative Materials Division of the NAHB Research Center; and by Damian Pataluna, Division Manager of FischerSIPS, Inc., and Vice President of the Board of Directors of the Structural Insulated Panel Association.

Q. Why is Housing and Urban Development’s PATH program supporting this initiative?

A. Dana Bres: The PATH program’s goal is to make housing better, through the use of technology. We want Americans to have housing options that are more energy efficient, safer to live in, more durable, more affordable — in a word, “better.” Some time ago we identified three technologies that we determined had good potential to do that: insulating concrete forms (ICFs), light-gauge steel framing, and SIPs. We have already accomplished creating prescriptive standards for ICF construction and for steel framing, and those standards have been incorporated into the building codes. A SIP prescriptive standard is the remaining one still left to accomplish.
Part of PATH’s purpose is to provide information so that builders and homeowners can make more informed decisions regarding housing. With prescriptive rules in the code, we open up the opportunity so that a builder, without having to go get an engineer to seal a set of plans, will be equally able to offer a consumer wood framed homes, steel framed homes, insulating concrete form homes, and structural insulated panel homes. So now everyone will be able to select, from this suite of technologies, the one that works best for any particular project.

Q. What is the role and function of NAHB Research Center in the project?

A. Nader Elhajj: NAHB Research’s job is to support PATH’s goal of leveling the playing field between wood-frame construction and the alternative technologies. PATH is providing all the funding for this effort, and we are doing the work. So we will be putting together the steering committee to oversee and advise the project, we will collect and analyze information from members of the SIP industry, and we will draft the proposed prescriptive standards and put them into code language.

Q. Why has SIPA’s Board of Directors voted to go forward with this process?

A. Damian Pataluna: SIPA believes that this initiative is really going to help launch our industry. We have had a goal for some time of reaching a five percent market share in the homebuilding industry. But we have been held back from accomplishing that in large part by the lack of building code acceptance. When a builder brings SIP plans to the building department, the building official typically covers himself by requiring an engineer’s or an architect’s seal. That adds $800 to $1000 cost to the project just for the professional fee, as well as added cost for details the engineer may specify that may not be entirely necessary. There is also the cost of a typical three-week to six-week delay for getting the engineered analysis done and approved. But once a prescriptive method is written into the building codes, you will be able to use SIPs as a standard building material, without having to get an engineer's seal or stamp on your plans. We have been discussing this idea for several years, and it is very exciting that we are finally getting started with it. We expect this to bring more interest and awareness as well as investment into the SIP industry, and open the way for a major expansion of our market.

Q. How do we know that putting SIP methods into the code will have an effect?

A. Nader Elhajj: Well, the inclusion of ICFs and steel studs into the building code is already making a big impact for those industries in just a short time period. Each of those industries has its own way of tracking those numbers. The Steel Framing Alliance, for instance, keeps track of the number of steel framed homes erected every year, as part of the builders’ practice survey that NAHB Research does every year at the International Builders Show. And the data on that are shown on a chart at their website. They are seeing a big increase, and part of that can be attributed to the introduction of their technology into the building code, and the building officials having this information in front of them so that they don’t have to second-guess the method any more. When we first started working with the steel framing industry back in the mid-1990s, there were only about 500 steel framed homes being built every year. Now it has gone up to about 35,000 or 40,000 homes annually. The ICF industry has also seen a big increase. So it is reasonable to expect that a similar increase in the market could occur with SIPs when that technology is also introduced into the body of the code.

Q. When certain specified details are written into the code as a prescriptive method, does that mean other details that are being used already will no longer be allowed?

A. Nader Elhajj: No, not at all. That is a common misconception, but in fact the prescriptive parts of the code do not limit the builder or designer to code-specified methods. The code tells the builder, “If you follow these prescriptive rules, you don’t need special approval — you can just do it. But if you are doing it some other way, you have to provide local authorities with substantiation that the way you are doing it is correct.”
Dana Bres: There is nothing in a prescriptive method that rules out other methods. It’s just like with the prescriptive rules for wood framing today: You don’t have to ask anyone’s permission to build a wall with 2x4 studs 16 inches on center — you just do it. But the code allows you to build with studs 19 inches on center if you want to — you may annoy a lot of people, but all you have to do is show that it will work. By the same token, with SIPs, if a prescriptive method were to go into effect tomorrow, a product manufacturer or a designer who had some innovative way of using the material would not be prohibited from doing the same thing that they did yesterday, the day after tomorrow when the prescriptive method was accepted. However, to do that, they would still need to document that their method will satisfy the same minimum requirements as the prescriptive method does.
Nader Elhajj: Some manufacturers have said to me that their product is superior to what the prescriptive method might require. But if the structural or other capabilities of a product or method meet or exceed the minimum permitted by code, that product or method will still be able to satisfy the code requirements as long as they can document the advantage. And the prescriptive method will now give them the opportunity to market and publicize that advantage as being superior to the code-required minimum.

Q. How are the details and product characteristics going to be selected for inclusion in the prescriptive method?

A. Nader Elhajj: We are going to follow the same methodology we did with steel and icfs. When we started to create the steel framing provisions back in 1994 that are now in the building code, there were more than ninety different manufacturers roll-forming steel studs, and every single stud was different. Every manufacturer had their own sizes, their own dimensions, their own method of connection – they were similar, but not identical. The biggest hurdle was to standardize the product. And it took a long time for 90-something suppliers to agree on one standard set of products.
However, it’s also true that the steel products were very similar because they were all variations of a basic C-channel shape. The SIP industry is more like the ICF industry, where you find a variety of different shapes used for concrete form products: Some are waffle-shaped, some have smooth faces, et cetera. For ICFs, we ended up proposing a set of general criteria for three main types of form systems, and eventually the manufacturers saw that it was worth the effort to adapt to one of those three types and meet the criteria, in order to get the opening up of the market that they got by creating a standard within the code.
We will be working very closely with SIPA to gather the information on all the SIP systems that are now being produced in the market — learning all the existing product characteristics and collecting the data on their performance capabilities. Then, probably, we will do something like what we did with the ICF industry, and propose generic standards for several main types of product, so that the product standard will be as broad and inclusive as it is practical to be. Then we will have some discussions and revise the standards as need be in order to get broad agreement in the industry that these are good standards. And the same general process will be applied to create the prescriptive methods for making panel connections and building panel assemblies for erecting house structures.

Q. When will this standard finally appear in the building codes?

A. Dana Bres: We hope to have all the test data that the industry has already invested in, collected and summarized and assessed by summer. We will be relying heavily on working with the industry to organize existing test data, and then we will perform additional structural testing as necessary. Then, by late summer or early fall we plan to have an early draft of the standard, and have a final version written in code language by the end of the year, and propose it for acceptance into the building code.
The 2006 edition of the building code will already be going into print by that time, so the next building code edition that we will have the opportunity to be included in is the 2009 edition. However, we are going to work to try to have the prescriptive standard published as a supplement to the 2006 code. A supplement to the code carries much the same weight as the main code, for some building departments, and it can be used to demonstrate code compliance. And if the standard is adopted as a supplement, we will then be lined up for quick acceptance into the main code book for publication in 2009.

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