Residential Buildings

Now that the State and Counties have adopted the new International Energy Conservation Code (IECC), specifiers and contractors need to be aware of alternatives that may be used instead of costly continuous foam insulation. For residential construction, the State has added exceptions to continuous foam. 

Once the four Hawaii counties adopted the 2006 IECC, many Hawaii steel framers were faced with complying with the new requirements. Adding continuous foam insulation has a significant cost impact on the construction of new homes. Not only will the builder have to take a look at the cost impact of the foam board, there are also additional costs for the washered screws to attach the foam to the framing, treated lumber trim boards to fur out the windows and doors to make up for the added thickness, extensions for the door thresholds, and a vinyl drip seal that is installed at the bottom of the wall.

Fortunately, in 2012, the Hawaii State Building Code Council approved a set of amendments to the 2009 IECC which included trade offs for the R-5 foam insulation. The four Hawaii Counties, while still on the 2006 IECC, will allow the use of the 2009 State IECC if it is referenced in the energy calculations. A copy of the State Amendments may be found here. The R-5 continuous foam trades offs may be found in section 3.181-15.

Otherwise, one could use the REScheck program, which is a free download from the DOE, and recognized by the City & County of Honolulu. (Please note that REScheck has removed the 2006 code provisions from their latest download. The older version has more trade offs available for steel framing. For a copy of REScheck program v4.4.4.2, please email [email protected] A copy will be provided to HSA Members compliments of PNNL.)

Using a combination of energy saving components such as windows and better SEER mechanical equipment, a steel framed home in Hawaii can still comply without adding the costly foam board. Many HSA members have benefited already from using these alternatives, or the REScheck program.

If you have any questions, please contact HSA Code Committee Chairman Tim Waite.