# Insulation question



## VillageInspector (Feb 28, 2019)

I was told at an annual state training course that its required by NYS energy Code to staple the insulation flanges to the face of the stud rather than the side of the studs. Just recently I was challenged on this and I went into the energy code but came up empty. The IRC and IBC don't seem to offer any guidance either. What's everyone's opinion on this ?

Thank you


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## khsmith55 (Feb 28, 2019)

Manufacturers installation instructions have ALWAYS required the flange to be stapled to the face of the stud. I have pi.....ed off a lot of contractors over the years pointing this out. My specs have always said thi but know one seems to read anymore.


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## jwilly3879 (Feb 28, 2019)

There is absolutely nothing in the Code about the location of staples. Installation instructions I have seen allow either face or inset stapling. I had a go round with this very issue and contacted NYSDOS about it and either method is acceptable. Some sheetrockers will not install over face stapled insulation because of screw pops. Also, if face stapled the drywall cannot be glued or sealed at he top and bottom plates. It was also argued that it would not be continuous vapor retarder if inset stapled but the flanges on kraft faced insulation are only paper and again the word continuous is not mentioned with regard to vapor retarders.

https://www.certainteed.com/resources/TB__76_-_Stapling_Methods_and_Faced_Insulation_Products.pdf


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## steveray (Feb 28, 2019)

Why would the drywall have to be glued?


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## Pcinspector1 (Feb 28, 2019)

steveray said:


> Why would the drywall have to be glued?



R702.3.1 allows adhesives if conforming to ASTM C 557. 
Table R702.3.5 has applications with or without adhesive.

So if no poly is being used and the batt tabs are on the inside of the stud, adhesive can be used to reduce fasteners,  reducing visual drywall appearance issues.


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## mtlogcabin (Feb 28, 2019)

2018 IECC
Exterior thermal envelope insulation for framed walls
shall be installed in substantial contact and
continuous alignment with the air barrier.

If you staple to the side of the stud the insulation will not be in substantial contact with the air barrier (drywall)


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## Pcinspector1 (Feb 28, 2019)

On the 2009 IECC, can't find that section?


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## jeffc (Feb 28, 2019)

An insulation installer convinced me that a non-continuous vapor barrier is not the biggest offence you will ever encounter. It is the warm moisture laden air passing through the exterior envelope that is the cause of moisture damage. Let’s compare a non-continuous vapor barrier vs. a leaky house.

The vapor barrier with holes or gaps at studs will allow water molecules into the cavity, through diffusion, at a rate of one molecule at a time. Yes, one molecule at a time. How many molecules before you have a problem?

How about a leaky house? Visualize warm moisture laden air traveling through exterior wall due to stack effect or prevailing winds. Warm moisture laden air moves from inside, through the exterior envelope to the outside. As this air cools while moving through the exterior envelope, it loses its capacity to hold  moisture and deposits it on the closet solid object: a stud, bottom plate or exterior wall surface. Think relative humidity, as the air cools, the relative humidity increases. Leaky houses cause moisture problems.


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## jwilly3879 (Feb 28, 2019)

Inset stapled insulation only has a small area that is not in contact with the wall covering. "Substantial" is a subjective term, is 90% substantial, I would guess there is more contact than that. It has been argued that convection currents will occur along the studs but if the drywall is sealed to the top and bottom plates (as we do) no air is introduced to the cavity and there is no stack effect.


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## ICE (Feb 28, 2019)

This is one of those questions that should not be a question.....not for the last forty years.


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## Sifu (Mar 1, 2019)

FWIW


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## Pcinspector1 (Mar 1, 2019)

Sifu's post, OC R30C insulation; There you have it, insulation can be stapled to the face or the side.


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## tmurray (Mar 4, 2019)

jeffc said:


> An insulation installer convinced me that a non-continuous vapor barrier is not the biggest offence you will ever encounter. It is the warm moisture laden air passing through the exterior envelope that is the cause of moisture damage. Let’s compare a non-continuous vapor barrier vs. a leaky house.
> 
> The vapor barrier with holes or gaps at studs will allow water molecules into the cavity, through diffusion, at a rate of one molecule at a time. Yes, one molecule at a time. How many molecules before you have a problem?
> 
> How about a leaky house? Visualize warm moisture laden air traveling through exterior wall due to stack effect or prevailing winds. Warm moisture laden air moves from inside, through the exterior envelope to the outside. As this air cools while moving through the exterior envelope, it loses its capacity to hold  moisture and deposits it on the closet solid object: a stud, bottom plate or exterior wall surface. Think relative humidity, as the air cools, the relative humidity increases. Leaky houses cause moisture problems.



It depends on the climate the building is constructed in. 

Diffusion is the rate at which moisture travels through a material or assembly. So, how fast water will move from one side of gypsum to the other. Even vapour barrier permits some water into the cavity through diffusion. 

Air leakage on the other hand simply carries  moisture laden air into the cavity. This happens any time that the building is at a higher pressure than the surrounding environment. 



But the insulator isn't wrong. You don't need a continuous vapour barrier. In fact, many assemblies perform better without continuous vapour barriers. Air barriers on the other hand, must be continuous or you will see moisture problems regardless of your climate.


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## Enrgxprt (Dec 5, 2019)

Code instructors can sometimes be off a bit. If the tabs are pushed back, exposing the sides of the studs, the insulation is compressed. Too much, and the r value is reduced and enough of that is bad... 

How bad? So RESNET has an insulation grading method. Perfect, as per manufacturers instructions, everything split around plumbing and wiring and pretty much in full contact with the surface intending to keep warm called Grade 1, 2x4 wall R13 (with studs into account) would have an r value of 11.7 (including well done side stapled tabs) 
Small areas of compression here and there and maybe some gaps here and there would be R 11.1 or grade 2

Any wall where insulation wasnt split around wires and plumbing get Grade 3 and that average R value is 10.3 

So, that 2x4 wall, best to worst is difference of R1.4
Say thats 1000 sq ft of wall at a 55 degree temperature difference, equals 660 btu more loss per hour.  Not too big of a deal. (U×A×Dt) 

Whats makes bad juju in walls is convective air currents moving vertically in the cavity. Fiberglass lets air move easily, and depends on still air to perform. Long areas of compression or gasp, knee walls with an open back will create a loop, reducing the value even more and why encapsulation is so important.. 

So, if the edges of the tabs are all even with the face of the stud the 3/4" of compression is negligible, and certainly installed well enough. 

Consider dense pack cellulose installed before sheetrock, the netting is stretched taught by stapling down the sides of studs to help stretch the fabric across the bays and to prevent  pillowing out too much (preventing the rock from sitting tight to the wall) The real things CEO's should be looking for is insulation split around wires and plumbing, and that the insulation is mostly in contact with the surface it intends to warm. Other  things like insulation in walls covered on sides, wind wash baffles and sealing rock to top plates.. The difference between face and side staple might be bigger with vapor transport, but if the cavity (sheathing) is airsealed, air will not move through the assembly. Im in a pretty close to vapor nutral area. 2 coats of paint is all we need here, so side staples vs face staples dont matter too much at all.


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## mtlogcabin (Dec 6, 2019)




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## Enrgxprt (Dec 8, 2019)

Fantastic image.. suspect the cavity to the left of the right window has heating pipes heading up to 2nd floor... 
Continuous insulation under rain screen would have significantly changed this, although glass is like a hole in the hull... 
Doesn't matter how watertight the other 95% is, if the bildge pump cant keep up, a sizable hole will make the ship sink.. 
Heating equipment works with the same analogy as a bilge pump.. 

Toss into this mean radiant temperature, and you have what I live in, A home built in the 50's and one that's only comfortable if the TT reads well above design...
Cold walls, Cold ceilings, and even colder glass makes my body the warmest thing in the room. While some may think this is snake oil, 
its huge in the comfort game. 
When walking past a cold glass window in the dead if winter, the cold you feel is not "cold coming to you" its heat leaving your body faster than your body can replace. Regardless what intuition tells you, heat moves to cold. End of story. Ice cubes don't get more cold if left on a table. 

Could go on and on, but this deserves its own thread. As Im new here, not sure if my rant would be well received....


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## jar546 (Dec 8, 2019)

Enrgxprt said:


> Fantastic image.. suspect the cavity to the left of the right window has heating pipes heading up to 2nd floor...
> Continuous insulation under rain screen would have significantly changed this, although glass is like a hole in the hull...
> Doesn't matter how watertight the other 95% is, if the bildge pump cant keep up, a sizable hole will make the ship sink..
> Heating equipment works with the same analogy as a bilge pump..
> ...



I am sure that your possible expertise would be well received and appreciated.  Not all will agree and some may be argumentative just to argue but I am sure you can professionally vent here.


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## mtlogcabin (Dec 9, 2019)

I have witnessed about a dozen blower door test when it is 20 degrees or less that the state will conduct with an infra ray camera and it is amazing the cold spots that appear on even interior walls. It is an eye opener for everyone that sees it.


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## Enrgxprt (Dec 13, 2019)

The problem with this Building Science stuff is abbreviated is B.S. BUT the other problem is we have been beat into submission for so long that any change feels (quite literally) uncomfortable. I know first hand this discomfort. Every bone in our body believes this is wrong. With all of the training and education, it still took time for it to finally click for me (Talking years..)

The great thing about this is the science is easy to learn in bite sized chunks. 
Not unlike a 500 piece jigsaw puzzle, learn and understand each piece and one day you wake up and see the big picture. 
This is what I love about this end of it. In the last 10 years I have not come across one problem (building science related) I couldn't solve. No matter how complicated, you find is always due to something silly. Hundreds if not thousands of homes later, and never one customer cooling, heating or comfort complaint. 
Thing is, some folks dont care about how a car works or how anything works. They dont want to learn, and are just looking for the $$$

Most of what I call dream customers, you know the ones who value your service, ask hundreds of questions and pretty much dot every I and cross every t, usually call me after being in the home for some time and say, OMG, I can not say how amazing my house is, or I had a hard time believing 4,500 sq ft only needed 2.5 tons of cooling but this summer that week when it was 95, my house was so amazingly comfortable every where... 

The other problem, which is huge is actually 2 fold. One, you shouldn't apply any of this stuff UNTILL you know every angle. Like any high performance race car, alot can go wrong quickly. My best advise is #1 Build Tight yes, but ABSOLUTELY ventilate right. The other issue here is, and I hate to brake it to you, not everyone you trust to understand the BS actually does. I have literally lost faith in man kind over this realization over 10 years ago. I can easily pick out thousands of homes that are time bombs because the people hired had zero knowledge of the most fundamental aspects. Sure, they are like ballerinas on the dance floor, great talkers, get along with everyone. They spin tales well and are believable but honeslty have zero clue... Ahh.. Im falling off the deep edge, you get the idea....


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## Elior Rosenkrantz (Mar 7, 2021)

The blower door test is becoming more common in Philadelphia. We conduct them at the post construction phase but I do think it would be beneficial to conduct it while the walls are exposed so that problems can be found and corrected ahead of time. The blower door is an incredibly useful tool for keeping the building air tight.

Ori Rosenkrantz
BlowerDoorTester.com 
LocalEnergyAudits.com/blower-door-testing


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## mark handler (Mar 8, 2021)

*NOTE: CALIFORNIA *
2019 Residential Compliance Manual January 2019
The kraft paper used as facing on thermal batt insulation material is typically a 
Class II vapor retarder. Faced batts may have flanges for fastening to assembly 
framing. *Fastening flanges may be face- or inset-stapled or not stapled at all*, 
as the flanges provide no moisture control.* Face stapling* of flanged thermal 
batts helps ensure the insulation material is installed fully and properly within 
the framed cavity. Flangeless batts are also common and require no fastening 
as these materials maintain installation integrity through friction-fitting within the 
cavity of framed assemblies. In all cases, the insulation must be installed 
properly.


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## classicT (Mar 8, 2021)

Elior Rosenkrantz said:


> The blower door test is becoming more common in Philadelphia. We conduct them at the post construction phase but I do think it would be beneficial to conduct it while the walls are exposed so that problems can be found and corrected ahead of time. The blower door is an incredibly useful tool for keeping the building air tight.
> 
> Ori Rosenkrantz
> BlowerDoorTester.com
> LocalEnergyAudits.com/blower-door-testing


FYI, unless you are a paying sponsor, I don't think you are supposed to post your website as free advertisement, and all 4 of your posts have your websites on them.


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## Elior Rosenkrantz (Mar 8, 2021)

Noted


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## Enrgxprt (Jun 10, 2021)

VillageInspector said:


> I was told at an annual state training course that its required by NYS energy Code to staple the insulation flanges to the face of the stud rather than the side of the studs. Just recently I was challenged on this and I went into the energy code but came up empty. The IRC and IBC don't seem to offer any guidance either. What's everyone's opinion on this ?
> 
> Thank you


If you have been part of the latest energy code trainings, you would have heard the speaker talking about insulation grading. While its not in our code books, it is by refrence with the HERS ERI path. Grade 1 fiberglass can be achieved by side staples. Alway has been able to. For those who say it MUST be face stapled, i challenge you to find where it actually states it in any manufacturers literature. The vapor barrier most often forget about is the two coats of paint, in addition to the cavity paperface. But the biggest barrier is an air tight wall or ceiling by a huge factor. How many folks Here know that the top plate needs to be sealed to the drywall where ever there is an attic space above ? Code is often written poorley, but durable gasket (best) or caulking (yuk) on the lower of any top plate, exterior walls and partition walls, is the best way to reach 3ach50. And required. 
That is a tremendous vapor barrier...


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## steveray (Jun 10, 2021)

Yep...Seal them up and let hem rot because no one knows how to waterproof the outside....


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## Enrgxprt (Jun 11, 2021)

Liquid water a problem for sure. Water vapor another issue, it often rains and becomes liquid, inside a wall.. Vapor profile (in or out) is the key. A reservoir,  something that prevents movement of water (liquid or vapor) is what knuckleheads build in the name of energy code all the time. Its stuff like this that gives BS a bad name.. Too many people took a 3 day class, passed a test and consider themselves experts..  How many here saw closed cell foam in the cavity with foam on the outside as well? Knuckleheads built a wall that cannot allow moisture to move in or out. The saying, all windows leak, at one point in there life, they will. Now the sheathing will rot because it cant dry to any direction. Im all for conservation, more for savings but 100% for comfort and durability. If that was the focus, may be, just may be folks might learn


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## No Soup for you (Jun 15, 2021)

I have gone around and around with regards to stapling the insulation, I dont care as long as its not compressed , cut outs are proper at electrical boxes and plumbing etc....



The energy code is also a little ridiculous. (in my opinion)

You now make the house so tight,  you now need to put some holes in it with fans to changeover the air every day.

Seems like a waste and "energy" to me.  

I like my leaky old house, i get fresh air w/o opening a window. HAHA


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## Enrgxprt (Jun 15, 2021)

No Soup for you said:


> You now make the house so tight,  you now need to put some holes in it with fans to changeover the air every day.
> Seems like a waste and "energy" to me.


Yea, I get it. Its a tough one to grab a hold of.  The difference is with the two words,  Controlled Vs Uncontrolled.  The Energy code (and Building Science) is suggesting that infiltration witch is uncontrolled is bad.  
If its not controlled, the amount of infiltration, and when it happens is NOT up to anyone but temperature difference (Stack effect) and how loose or tight the home is. Believe it or not, some houses are built tight without knowing it.  It doesn't happen often, but it certainly does.

The code (And BS) also is trying to separate the uncontrolled infiltration  from being considered ventilation.
I in a previous life built  hundreds if not thousands of new homes.  Every bone in my body fought this with  "Well it has to breath"..
Personally, this sentience made perfect sense because I didn't understand everything about it.  

The walls in a house separating inside and out need a vapor profile. We need to breath. End of story. No, really, that's it. 
Walls, floors appliances dont have lungs.  Stop being sillly. 

Walls where there is a temperature difference (winter and summer) on one side vs the other is your building envelope. 
That's where the R (Resistance to heat, R-Value etc) should be. If R is anywhere else, its a waste unless its for sound proofing.

That wall or roof with a temperature difference, heat will travel one way. Always from hot to cold.  When It moves, it carry's moisture with it.
In a tight home, its movement is limited to diffusion. In a loose home, mass air transport.  They are like comparing the hair on an ants leg to a tree trunk.
A vapor profile allows moisture to move in, out or both through diffusion. No vapor profile creates a reservoir . Great for storing liquid water, but horrible for wood/sheetrock or anything that can be damaged by water.... Mass air transport moves gallons vs molecules with diffusion.

The thing I hate most about this surge in Building Science is it was wrapped up with a crappy Energy Conservation tag line.  Sure, a byproduct is saving.
But the sale should have been made on comfort, durability, health and safety and LASTLY, Oh yea, you will save a huge amount in utility bills.

Oh, the last peeve... Some "woke" (lolol) code official complaining about pulling air in through the home, by using exhaust only as ventilation... Hey knucklhead, ya think the loose home does it less ?? Get real... A house at 7-10 ACH natural is pulling in WAY more air (through those gaps) than the tight house with ventilation. But all of a sudden, you have a problem with it? KNUCKLEHEADS lmao.. Build it TIGHT and ventilate right. The infiltration areas more then likley will be around windows and doors, and not from the crawlspace.... or worse..
Whew... that felt GREAT lol ...

I am not a greenie. No offense to those who are. I smoke, ride a Harley and shoot guns. Im the last guy in the world thinking the changes here in the US can offset what the rest of the planet does, I hardly think it will make any difference.   Those who are "green" god/buda/ or whatever bless you. 
What has me sold on this is building a bunch of great houses and being part of a bazillion more successful jobs, where everyone involved from the HVAC guy,  the owner and builder are in disbelief with how well the home performs.

1) AC guy calls me on a Sunday, crazy hot spring weekend. House closed up since mid week the week before. The 1st contracotr to unlock the front door in 4 days. Cannot understand why the house is 65 degrees, 90 outside and the OUTDOOR UNIT WAS NOT SET YET lolol...
The house managed to keep cool for two days, without AC and being 4,000 SQ FT. Now undersatnds why 2.5-3 tons was more than enough.

2) Builder wants to get oak delivered, middle of June 90+ degree days and 80 degree nights, house is too humid and subfloors not dry enough. No power at fuse panel, meter not set yet. Utility 2 weeks behind. Builder has huge generator, huge lot of land, goes to HD any buys 2 window unit AC's  Sets them up at 4PM. Does not want delays once power is on... Comes on job late next AM and does not hear the AC units running, now worried his plan wont work. Cracks the front door open and finds his 5.5k sq ft house is at 65 degrees.  (2)  1 ton window units. Calls me with OMG Im a convert, I didnt believe you at first but took the leap of faith... 

3) Successful restaurant owner building 6k sq ft, on a cliff overlooking water. Almost all glass North facing. Almost nothing west or east (neighbors) and very little south facing.  Meaning no cooling loads. He is convinced to follow my recommendations. Figuring he will sue me if it doesn't work (my guess anyway)
3 tons of cooling, finished basement, 1st floor, 2nd floor and conditioned attic. Calls me 8 months after, hottest days of the summer gushing with how comfortable his house is.  Says his AC guy, builder and electrician, plumber all warned him. They are all now in disbelief, cant understand  how Manual J and Rem-Rate called it. 

4) Small 1,100 sq ft house. (1) 550 gallon tank of oil.  every two years.  (5750 HDD 15deg winter design)

I could go on, but nuff said. The stuff isnt BS. Its BS. What it takes is someone to cross every or most t's and dot most every i. 
You cant build anything high tech half assed without failure.  I can guarantee, any **** show story you have ever  heard of is becuse people or a group of them had half a clue. 
Tight, vapor profile, ventilate, don't oversize anything done...


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## tmurray (Jun 18, 2021)

No Soup for you said:


> I have gone around and around with regards to stapling the insulation, I dont care as long as its not compressed , cut outs are proper at electrical boxes and plumbing etc....
> 
> 
> 
> ...


It may be a waste of energy in moderate climate zones, but anywhere with a significant number of cooling or heating days, mechanical ventilation makes way more sense. Having 7-8 air changes per hour in a house means you are paying to heat or cool the outside air to whatever the design conditions are that many times per hour (assuming pressure differential with outdoor). With proper air sealing, you get that number down to 0.3. The mechanical system is either an ERV or HRV, meaning that energy lost by ventilation without mechanical systems can be recaptured. Typically, mechanical ventilation is 20-30 times cheaper than the alternative.

The bad things about no mechanical ventilation:
1. There is no way to control your house ventilation. Want to get some fresh air, but no wind and the same temperature inside and out? tough luck. Do you want to not have ventilation? You might get it anyway. 
2. You're pulling air through the building envelope, so it's picking up whatever particles of random crap is in the building along the way. 
3. You are getting nice cold air blowing into your house in winter where I live and really hot air blowing into your house in cooling climates. Hope you like feeling drafts!

Our builders love that we have started checking vapour barriers. One building in his 80s once told me that he spends less than 10 dollars fixing drafts now where before he was spending over 1000 dollars after the client moves in because he needed to rip off trim, cut sheetrock, etc. to try to trace and repair drafts in homes. We just find areas that are not sealed well and point them out. A lot of time now, we are met at this inspection with a guy who has a bunch of different air sealing products and he walks through with us hitting anything we point at.


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## Min&Max (Jul 14, 2021)

The energy code stuff is interesting and overall contains a lot of nonsense. I find ResCheck to be a big, hot, pile of steaming "stuff". We adopted the 2018 IECC and then basically amended out every bit of it. We now have a bit more than a single page document that exceeds ResCheck. Contractors love it and so do I because every single dwelling meets a well defined minimum standard.


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## ADAguy (Sep 14, 2021)

Excellent topic coverage gang, thank you all.


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## Glenn (Sep 15, 2021)

khsmith55 said:


> Manufacturers installation instructions have ALWAYS required the flange to be stapled to the face of the stud. I have pi.....ed off a lot of contractors over the years pointing this out. My specs have always said thi but know one seems to read anymore.


This is not true.  Many manufacturers specify either.  Example:  https://www.certainteed.com/resources/IGInstallationBasics200608.pdf

[EDIT] Sorry for duplicity.  I see many others already covered this example.


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## bill1952 (Sep 15, 2021)

Min&Max said:


> The energy code stuff is interesting and overall contains a lot of nonsense. I find ResCheck to be a big, hot, pile of steaming "stuff". We adopted the 2018 IECC and then basically amended out every bit of it. We now have a bit more than a single page document that exceeds ResCheck. Contractors love it and so do I because every single dwelling meets a well defined minimum standard.


Can you share your single page document? Thanks!


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