CI Requirement

[unegamacated]

Our office does a lot of TI projects in new shell buildings. More often than not the shell building does have CI as required per the IECC (06, 09, 12). Is this not required or is there a work around?

 

[Mech]

More often than not the shell building does have CI as required per the IECC (06, 09, 12).

Did you mean they DO NOT have CI as required?

COMcheck (free software at www.energycodes.gov/comcheck) allows alternate insulation values and techniques. Verify COMcheck is allowed (by the state, AHJ, whoever makes that decision for your project) as an alternate to the IECC.

Browse through the tech support documents when you need to fall asleep. It will tell you the assumptions made (materials and thicknesses used) in the program to generate the R and U values. I end up inputting my own assembly values because our building construction types hardly ever fit the available cookie cutter selections.

 

[unegamacated]

Thanks for the correction does not have CI as required.

I realize they are alternate ways to meet the code but I don't see how you get around no CI!

 

[Mech]

Not sure which version of IECC you are trying to comply with. With the older versions, I think we used extra fiberglass in the walls, heavier insulation in the roof (I do not recall if it was fiberglass or rigid) and heavily insulated doors. Whether all that was installed or not is another question.

 

[Frank]

That is an issue we have been dealing with the developers building new spec buildings that do not want to provide the insulation. Our position is it needs to be provided at the shell stage of construciton as almost any use requires heat and therefore energy code compliance.

 

[unegamacated]

Isn't the whole point of CI to minimize thermal bridging? So why would additional insulation on the roof, framed walls etc cancel out that requirement?

 

[Frank]

Isn't the whole point of CI to minimize thermal bridging? So why would additional insulation on the roof, framed walls etc cancel out that requirement?

Yes it is to reduce thermal bridging, in the past when insulation levels were lower adding additional cavity insulation could balance the effect of thermal bridging, current insulation requirements are such that that does not work any more where in some cases a R= 10000000000000 near perfect cavity insulation paired with thermal bridging would not meet the required overall U factor for the assembly.