08-14-2019, 01:23 AM
See section R401.2.1 Tropical Zone
Essentially, if you don't have air conditioning, no insulation in walls or floors required, and reduced ceiling requirements.
I think Hawaii is actually using the 2015 IECC with amendments.
https://energy.hawaii.gov/wp-content/upl...dments.pdf
The above changes up the ceiling insulation requirement a bit, with a higher requirement (R-19) if you don't have a reflective "cool roof", and a lower requirement (R-13) if you do.
A exposed beam ceiling should still work. One layer of 2" foam board on the roof plus a white (reflective) steel roof surface would meet the requirements of the code.
When I contacted the code people about details of insulation requirements and options for a shall we say, unconventional dwelling, they sent me a link to this:
https://energy.hawaii.gov/wp-content/upl...cy2004.pdf
Yeah I know it says commercial, but I was told you can use the commercial system of passing requirements. The advantage of this system, if applicable, is that it works in a radiant barrier as a option to reduce the R-value requirement. In some cases, a white roof combined with a radiant barrier removes the insulation requirement entirely.
They have several combinations of roof surface, insulation, and radiant barriers that are acceptable. They have a calculated value that combines the three things (insulation, reflective surface, radiant barrier) to give you a single number to pass. They call this the RHGP (roof heat gain factor). See section 6.
Essentially, if you don't have air conditioning, no insulation in walls or floors required, and reduced ceiling requirements.
I think Hawaii is actually using the 2015 IECC with amendments.
https://energy.hawaii.gov/wp-content/upl...dments.pdf
The above changes up the ceiling insulation requirement a bit, with a higher requirement (R-19) if you don't have a reflective "cool roof", and a lower requirement (R-13) if you do.
A exposed beam ceiling should still work. One layer of 2" foam board on the roof plus a white (reflective) steel roof surface would meet the requirements of the code.
When I contacted the code people about details of insulation requirements and options for a shall we say, unconventional dwelling, they sent me a link to this:
https://energy.hawaii.gov/wp-content/upl...cy2004.pdf
Yeah I know it says commercial, but I was told you can use the commercial system of passing requirements. The advantage of this system, if applicable, is that it works in a radiant barrier as a option to reduce the R-value requirement. In some cases, a white roof combined with a radiant barrier removes the insulation requirement entirely.
They have several combinations of roof surface, insulation, and radiant barriers that are acceptable. They have a calculated value that combines the three things (insulation, reflective surface, radiant barrier) to give you a single number to pass. They call this the RHGP (roof heat gain factor). See section 6.