# uhm.... I've never seen this.



## rktect 1 (Mar 18, 2010)

I have an existing ranch house at 1285 sq. ft.  A new 2nd floor addition is going on top for 1285 sq. ft.  The R-13 will go in the walls at 8' high.  The R-38 will go in the attic.  This is all on REScheck.  Then he added R-60 batt between the existing first and new 2nd floor in the 16" TJI @16" o.c.  And he passes by .4%.  Can he add insulation between conditioned spaces for an addition?  What is he insulating himself from?


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## vegas paul (Mar 18, 2010)

Re: uhm.... I've never seen this.

He may have two different HVAC systems up and downstairs... if he anticipates only occupying one or the other at times, this might make sense, but I agreee it is unusual.  Did the ResCheck take the R60 between floors into account?  I don't recall how that is done in ResCheck.


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## TimNY (Mar 18, 2010)

Re: uhm.... I've never seen this.

Seems strange, but I see nothing prohibiting it.

The way I look a it, if the 1st floor wasn't insulated at all, it would not only make more sense to put the insulation between the floors, but by putting the insulation in the space below the first floor you would be creating a nonconformity.

Otherwise you would have to verify U-Factor and existing insulation values on the first floor to be able to use insulation installed below the first floor.  They couldn't be required to bring them up to current code if they weren't compliant, yet the new addition must be.


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## rktect 1 (Mar 18, 2010)

Re: uhm.... I've never seen this.

The first floor is and always was livable space.  Probably r-13 in the walls and possibly only R-11.  SO why should he get R-60 between floors?


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## mjesse (Mar 18, 2010)

Re: uhm.... I've never seen this.

I agree with what TimNY says.

Bringing the second floor into compliance with the floor batts is cheaper than bringing the Complete (including 1st floor walls and windows) into compliance.

mj


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## codeone (Mar 18, 2010)

Re: uhm.... I've never seen this.

maybe hes just doing it for noise transmission.


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## JBI (Mar 18, 2010)

Re: uhm.... I've never seen this.

Sound attenuation?


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## rktect 1 (Mar 18, 2010)

Re: uhm.... I've never seen this.

Uh...no.  He needs it to pass REScheck by.4%  Without it he has to go prescriptive which means 2x6 walls with R-20 instead of R-13 in 2x4 walls. along with other items.


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## TJacobs (Mar 18, 2010)

Re: uhm.... I've never seen this.

Is part of the new addition over unconditioned space like an attached garage?  Maybe he's fooling REScheck so he can pass without really passing.


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## smeismer (Mar 18, 2010)

Re: uhm.... I've never seen this.

I suspect that he is gaming the program.  The program will automatically assign that floor area to either floor over unconditioned space, or floor over outside air.  In either case, the program will assume an enlarged exterior envelope.  Since that floor is heavily insulated, the average insulation of the exterior envelope is increased, and so by comparing it to a reference standard of a larger envelope, he passes.


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## Min&Max (Mar 18, 2010)

Re: uhm.... I've never seen this.

Question:  "What is he insulating himself from?"

Answer: ResCheck nonsense.


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## rktect 1 (Mar 18, 2010)

Re: uhm.... I've never seen this.



			
				TJacobs said:
			
		

> Is part of the new addition over unconditioned space like an attached garage?  Maybe he's fooling REScheck so he can pass without really passing.


Nope, he plans on insulating the 16" floor joist cavity between conditioned floors.


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## rktect 1 (Mar 18, 2010)

Re: uhm.... I've never seen this.



			
				smeismer said:
			
		

> I suspect that he is gaming the program.  The program will automatically assign that floor area to either floor over unconditioned space, or floor over outside air.  In either case, the program will assume an enlarged exterior envelope.  Since that floor is heavily insulated, the average insulation of the exterior envelope is increased, and so by comparing it to a reference standard of a larger envelope, he passes.


Ah ha.  That is where I see the mistake now.

His floor is shown on REScheck as a floor over unconditioned space, which it is not.  Now what to do about it?


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## peach (Mar 18, 2010)

Re: uhm.... I've never seen this.

resubmit based on actual conditions?

That would be my first choice...


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## Heaven (Mar 18, 2010)

Re: uhm.... I've never seen this.

That gets done around here all the time. Most of the time it is an attempt to control noise but sometimes to zone conditioned areas.


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## TimNY (Mar 19, 2010)

Re: uhm.... I've never seen this.

It is a good point, REScheck only has options for floors over unconditioned space or outdoor space.

However, I would think it is reasonable to accept.  If somebody submitted a REScheck for a floor over a basement, but selected over outdoor space rather than unconditioned space, would you accept it?  The insulation values would be higher.

Similarly, if he is selecting over unconditioned space and the space is conditioned, should it be accepted?

If they are adding a second floor to an uninsulated house, do they have to insulate the whole house?  I know you say the house is already insulated, but the precedent you set today should be applied to the uninsulated home that comes across your desk tomorrow.

If they are adding an addition _off the back_ of an uninsulated house, do they have to insulate the whole house?

I don't see anything in the definition of "BUILDING THERMAL ENVELOPE" that conflicts with what they propose.

Would it be better if they used prescriptive methods, R-21 in the wall and R-19 (assumed value) in the space between floors?  Why would it be different?

Just asking the questions, I'm really not passionate about it one way or the other.  I personally would allow it.


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## vegas paul (Mar 19, 2010)

Re: uhm.... I've never seen this.

ResCheck is designed to measure the thermal envelope of the home - the floor joist fill area described above is not part of the thermal envelope, therefore it should not be included in the calculation.  Perhaps there is a more sophisticated tool, other than ResCheck, that could assign some value to this insulation, but ResCheck always treats it as thermal envelope, so using this insulation in the calc skews the result.


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## TimNY (Mar 19, 2010)

Re: uhm.... I've never seen this.



			
				vegas paul said:
			
		

> ResCheck is designed to measure the thermal envelope of the home - the floor joist fill area described above is not part of the thermal envelope, therefore it should not be included in the calculation.  Perhaps there is a more sophisticated tool, other than ResCheck, that could assign some value to this insulation, but ResCheck always treats it as thermal envelope, so using this insulation in the calc skews the result.


By definition, it is part of the thermal envelope.  The definition of building thermal envelope includes "floors" (as opposed to "_exterior_ walls" as specified in the definition) that enclose conditioned space.

Indeed the proposed insulation is in a floor and encloses conditioned space.

The only problem I see (not a problem for me, but I could understand if other AHJs went the other way) is that REScheck does not have a floor option "over conditioned space".

That being said, I do not see how you could prevent the prescriptive values from being used.


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## rktect 1 (Mar 19, 2010)

Re: uhm.... I've never seen this.

He isn't using prescriptive values.  Here he would need R-20 or R-13/R-5 in the walls.  He only has R-13 in the walls.

Could he change this?  Sure, but that isn't my call.  I have to accept or deny his REScheck at this point.  But I don't see how adding insulation into the floors does any good at all.  All it does is waste money on insulation without adding one single benifit to the thermal envelope.  I could place a pallet of insulation in the center of this room on the floor and it would have the same effect as he is getting.


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## rktect 1 (Mar 19, 2010)

Re: uhm.... I've never seen this.

I've been emailing REScheck DOE about this.  So far I have been told to change on the project tab from new construction to addition/alteration.  Once you do this go to the envelope tab and a new section called alteration details will appear.  Where the new addition attaches to the existing building, in my case the floor, that componenet would change to one of the options available.  Again in my case it was "alteration exposes a framing cavity but is filled with insulation".  He doesn't get to pick his R-value for this.  I am still trying to get more confirmation regarding this issue, but it seems more correct now.

And now this project fails by 13.5%.


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## FredK (Mar 19, 2010)

Re: uhm.... I've never seen this.



			
				rktect 1 said:
			
		

> I've been emailing REScheck DOE about this.  So far I have been told to change on the project tab from new construction to addition/alteration.  Once you do this go to the envelope tab and a new section called alteration details will appear.  .....


Putting on my dummy hat as I didn't even know that was an option.  Thank for the heads up.


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## TimNY (Mar 19, 2010)

Re: uhm.... I've never seen this.



			
				rktect 1 said:
			
		

> I've been emailing REScheck DOE about this.  So far I have been told to change on the project tab from new construction to addition/alteration.  Once you do this go to the envelope tab and a new section called alteration details will appear.  Where the new addition attaches to the existing building, in my case the floor, that componenet would change to one of the options available.  Again in my case it was "alteration exposes a framing cavity but is filled with insulation".  He doesn't get to pick his R-value for this.  I am still trying to get more confirmation regarding this issue, but it seems more correct now.And now this project fails by 13.5%.


Both the 4.2.0 and 4.3.0 versions of REScheck for NYS don't have this option (or I can't find it).

I will respectfully disagree on insulation between the floors not doing any good at all, but I respect your position on having to accept or deny the REScheck.


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## rktect 1 (Mar 19, 2010)

Re: uhm.... I've never seen this.

DOE REScheck personel called me up.  They now explained that REScheck is not a performance based software program but instead is a tradeoff program.  They told me that the floor has to be removed from the list.  So what I had said in my previous post was incorrect.  I still am not 100% certain what the alterations details does but they are specific about exemptions which they told me for my project I had none.

I was also informed that when a person wants to use spray foam insulation to be sure they are giving you the "installed" R-value and not the "effective" R-value.  Just FYI.  These should both be listed in the product specs.


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## peach (Mar 20, 2010)

Re: uhm.... I've never seen this.

You're never going to get the entire structure to comply when you add an addition to an existing, under-insulated home.... and it's not the intent to require it.. people will stop doing additions and renovations if they are required to replace all windows and insulate every existing wall.  Renovations are a significant revenue source for most building departments.


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## barlovian (Mar 22, 2010)

Re: uhm.... I've never seen this.

Are you permitted to use the prescriptive requirements in Table N1102.1?  If you are Zone 4, it looks like you could comply as long as the windows are 0.40.  If you are Zone 5, you do not have enough insulation in the exterior walls.  As a rough rule-of-thumb, if the new construction in your project meets all of the requirements in the table, you stand a good chance on ResCheck, as well.   If your addition does not meet all of the requirements in the Table, you will not pass ResCheck unless you provide trade-offs with insulation or U-factor beyond what is in the Table.

The first thing that I do when checking a ResCheck is to see how far the values for insulation and window U-factor deviate from the prescriptive table.   Well, not really.  The first that I check is location and code edition, but after that, I look compare the insulation and the windows with the prescriptive chart.


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## jim baird (Mar 22, 2010)

Re: uhm.... I've never seen this.

Insulation vendor sold him a "bill of goods"???


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## JBI (Mar 22, 2010)

Re: uhm.... I've never seen this.

There's a reason that the only options for new construction are 'floor over unconditioned space' and 'floor over outside air', as well as a reason for not having 'floor over conditioned space'. And that reason has been offered... ResCheck is about 'thermal envelope'. That is, it's about creating a conditioned environment _within_ the 'envelope'. Insulating the floor/ceiling assembly within the 'envelope' will serve no useful heat loss or heat retention purpose. It may attenuate sound, but not much else.

It would be comparable to putting page two of a letter in a second envelope, with seperate postage, to the same address. The recipient will probably still get page two, maybe even the same day, but they will nonetheless wonder why you wasted a perfectly good envelope and the extra postage...


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## STB (Mar 23, 2010)

Re: uhm.... I've never seen this.

The above information is also in the "HELP" section of the RESCHECK software.

TimNY,

Although you have merit to what you are saying, the bottom line is the program is only designed to take area adjacent to or above outside air or unconditioned space.  If you built a model of how this software was reviewing compliance based on th OP original description, there would be a 12+ cantilevered floor system in this house  :shock:

I've had my share of RESCHECK nightmares like everone else here.


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## TimNY (Mar 23, 2010)

Re: uhm.... I've never seen this.

I'm willing to concede not accepting the REScheck based on the program not having an 'over conditioned space' and leaving it at that.  I understand and agree with STB, the program is designed to work within the parameters offered.

However, "BUILDING THERMAL ENVELOPE" specifies the "floor", not the "lowest floor", not the "floor over unconditioned space", nor the "floor over outside air".  If we're going to bring thermal envelope into the mix, IMHO, the space above the first floor in this scenario could meet the definition of building thermal envelope.

Again, no huge personal interest, but am enjoying the thread.  Learn something new every day!


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## rktect 1 (Mar 24, 2010)

Re: uhm.... I've never seen this.



			
				TimNY said:
			
		

> However, "BUILDING THERMAL ENVELOPE" specifies the "floor", not the "lowest floor", not the "floor over unconditioned space", nor the "floor over outside air".  If we're going to bring thermal envelope into the mix, IMHO, the space above the first floor in this scenario could meet the definition of building thermal envelope.


Not according to the DOE personnel in charge of REScheck. Floor has to be removed from the program.


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## fw. (Mar 24, 2010)

Re: uhm.... I've never seen this.

From the ResCheck definitions:  Building Envelope

All components of a building that enclose conditioned space. Building envelope components separate conditioned spaces from unconditioned spaces or from outside air (see conditioned space). For example, walls and doors between an unheated garage and a living area are part of the building envelope; walls separating an unheated garage from the outside are not.

Conditioned Space

A space is conditioned if heating and/or cooling is deliberately supplied to it or is indirectly supplied through uninsulated surfaces of water or heating equipment; uninsulated ducts; or uninsulated floors, ceilings, or walls between it and another conditioned space.

Not sure how the rest of the country is doing it, but the ceiling between the first and second floors would not be a part of the thermal (building envelope) in my neck of the woods.

We would only look at the addition for compliance, not the entire structure though.


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## Min&Max (Mar 25, 2010)

Re: uhm.... I've never seen this.

Well it sure is encouraging to see this much discussion over an issue that an ounce of common sense should resolve. The existing part of the home should not be part of the calculation as it relates to the energy efficiency of the proposed addition. For the addition, use typical methods for your area that achieve compliance in a newly constructed two story home. Without knowing for sure what typically works in your area I would guess that .27 u-factor windows, R-19 exterior walls, R-49 ceiling and high efficient HVAC would be adequate.


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## rktect 1 (Mar 25, 2010)

Re: uhm.... I've never seen this.



			
				Min&Max said:
			
		

> Well it sure is encouraging to see this much discussion over an issue that an ounce of common sense should resolve. The existing part of the home should not be part of the calculation as it relates to the energy efficiency of the proposed addition. For the addition, use typical methods for your area that achieve compliance in a newly constructed two story home. Without knowing for sure what typically works in your area I would guess that .27 u-factor windows, R-19 exterior walls, R-49 ceiling and high efficient HVAC would be adequate.


I have been told that with REScheck, there is no longer a tradeoff for high efficiency furnaces when it comes to the 2009 code.

Maybe a performance based software program would work out.


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## rogerpa (Mar 25, 2010)

Re: uhm.... I've never seen this.



> Maybe a performance based software program would work out.


There is no HVAC trade-off allowed at all in the 2009 IECC.  http://publicecodes.citation.com/icod/iecc/2009/icod_iecc_2009_4_sec005_par007.htm?bu=IC-P-2009-000014&bu2=IC-P-2009-000019.


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## peach (Mar 25, 2010)

Re: uhm.... I've never seen this.

If you try  to include "old" construction into RES check or try to fit it into IRC chapter 11 as a total building, an addition is never going to comply.

Well, unless they gut the entire building and replace all insulation and windows..

IF the existing construction has no insulation, but they replace the windows with all Low-E windows.. maybe.

IF the existing construction has no insulation, no new windows.. but they add a high efficiency furnace.. it's it still better than it was?

IF the existing construction has no insulation, no new windows, no new furnace, but a new dual flush toilet .. it's better than it was.

Add.. common sense to the equation.


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## TimNY (Apr 7, 2010)

@rktekt and fw: Sorry for the confusion, in post #29 the "building thermal envelope" I referred to was in the energy code ie prescriptive requirements.  I agree with the consensus on REScheck, no good.

@min&max: on more than one occasion common sense and the code don't jive.  My take on the matter is the code prevails.


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## incognito (Apr 9, 2010)

TimNY

"@min&max: on more than one occasion common sense and the code don't jive. My take on the matter is the code prevails."

If the code and common sense do not jive I will go with common sense every time. Just because a bunch of us get suckered by the likes of Simpson and NFPA does not mean the AHJ cannot accept alternatives that are determined to be equivalent.


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