Air barrier requirements dealing with inspectors and builder
I am in the process of building a new home and have had some serious questions about some of the things being done.
I have a floor that is cantilevered over an exterior wall that has fiberglass insulation installed in the joist bays. There is also an insulated duct run to the far side (6′ or so) in one of the bays. I took it upon myself to put rigid foam board in-between the joists on the underside of the fiberglass, originally in just the duct run but then did all. This is not continuous.
I asked the builder if there was going to be sheathing installed on the underside of the joists and he responded by saying that “we can price it out”. After which vented soffit was installed over.
I did some digging and saw that there needs to be an air barrier at the exposed face of exposed insulation Table R402.4.1.1.
I called my local code official who said “air barrier, not sure what you mean by air barrier. Do you mean Tyvek?” (My Tyvek was not taped or sealed in any way). He suggested I talk with the builder and the project manager didn’t seem to understand what needed to be done either.
I then called and spoke with a supervisor at the company who contracts with the township about the issue, who again didn’t seem to know what I meant by air barrier saying I meant vapor barrier.
I sent everyone involved a copy of a PDF from the US Dept of energy https://www.google.com/url?sa=t&source=web&rct=j&url=https://www.energycodes.gov/sites/default/files/documents/BECP_Buidling%2520Energy%2520Code%2520Resource%2520Guide%2520Air%2520Leakage%2520Guide_Sept2011_v00_lores.pdf&ved=2ahUKEwjJ-MDK39LhAhUCKK0KHQVyDhcQFjAAegQICBAC&usg=AOvVaw0G6XXtejkSepYgjM9s3H5m&cshid=1555353749717 that details the things that need to be done to meet this mandatory part of the code (like continuous insulation or sheathing sealed at the perimeter and blocking at the sill over the wall), but the builder was saying it doesn’t apply because of “tradeoffs” which I think he is conflating with the prescriptive method.
He kept saying we could push up the blower door test, which doesn’t make the lack of these details code compliant.
I discovered other air sealing details that were poorly/not executed including blown cellulose behind the tub surround without an air barrier such as thermoply and no sealing of the rim joists.
Am I thinking about this wrong? If not what are my options as it seems no one is looking out for me.
Thank you,
Kevin
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Replies
Kevin,
Code or not, not putting at least a layer of taped plywood or rigid (much better) underneath the overhang will mean cold floors. The vented soffit can be reinstalled afterwards over it. Your cut and cobble helps but if it is hard to get it tight enough. Even if you have to pay for this, it would be worth to get it fixed.
Blown cellulose around a tub without a vapor barrier of some kind (6 mil poly or Kerdi) is a recipe for mold.
Kevin,
You're right, and your code officials are ill-educated. This situation is unfortunately common.
I don't really have any advice to give you. For decades, building codes have paid little attention to air barriers, so many code officials are ignorant about these issues.
Thank you for the comments. We shall see how everything shakes out, but it doesn't seem like it's going to go in my favor, as the builder is looking to the inspector for guidance and the inspector doesn't know anything.
Kevin,
What version of the International code is being used in your jurisdiction?
All codes include language referring to the need to seal air leaks. Although the code as written has many flaws, there are code provisions that you can use to argue your case.
It is the 2015 Michigan Residential Code which I am assuming follows 2015 ICC as it has Copyright 2015 ICC at the bottom of every page. The local jurisdiction references Michigan Building code.
Kevin,
See the screen shot below from the 2015 IRC.
Here is a link to the online version of the 2015 IRC.
There is more information in the code that you can refer to (beyond what is shown in the screen shot). See section N1102.4.1 and following.
Thank you very much for pointing this out. I think this is something the code official has delegated to the 3rd party energy audit that the builder selects and pays. This seems like a HUGE conflict of interest. I will have to do some digging and see if this is what is in fact what is being done, but I am almost positive that the builder alluded to the audit and blower door test.
Kevin,
More ammunition for you: I found the Michigan residential code online here:
https://www.michigan.gov/documents/lara/lara_bcc_2015_residential_code_502813_7.pdf
See the screen shot below -- the same air barrier requirements.
Kevin, I’m in Michigan so I might have some ideas for you. A lot of this is the same as anywhere else though.
There are basically three kinds of inspectors out there: 1- guys who make stuff up and do the “not in my city” thing. These are hard to work with. 2- There are the “by the book” people, who you can usually work with if you understand the code well and can explain how different things apply. 3- The third kind are the honest but clueless people. Sometimes these people can be educated, but they tend to be nervous about deviating from whatever they’re used to doing. See if you can get a meeting with some of your local building people, then go to the meeting armed with the info Martin has given you, the EPA/DOE stuff, and maybe a few articles from GBA, building science corp, etc.
If you have no luck working with the local people, you basically have two options:
1- get your architect/engineer to draw up air sealing details, then seal them and submit those. The seal carries a lot of weight, and will usually take care of any problems with the type 2 and 3 inspectors.
2- call the state of Michigan building people. They can overrule the local people, and they tend to be much more competent in my expierience.
You’ll still need your builder to do things properly. That might just mean you’ll have to be on the job site a lot more than you planned.
Note that in Michigan, some years back some laws were passed dealing with how city building departments are funded. The result was that many, probably most, cities now outsource a lot of the building plan review and inspection services. Some of these companies are pretty competent. I run into a company “safe built” frequently. I don’t know if they can help if your city doesn’t use them, but it might be worth calling them. They might be able to give you people in neighboring cities that know what you’re trying to do and can explain it to your city.
Bill
for any0ne looking for code info, this is a good resource:
https://www.energycodes.gov/resource-center
then simply select your state; in this case Michigan: https://www.energycodes.gov/adoption/states/michigan
If you select the residential tab, it tells you 2015 IECC with amendments; then lists the most significant amendments and then a pdf of "Residential Amendments" down below.
On airtightness note that a Michigan amendment is to relax airtightness required from 3 to 4 ACH50.
Peter
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There are several production builders in Michigan that I know have reputations for cutting corners. I wouldn’t be surprised if they lobbied for weaker code standards so that they could get cheaper builds to pass inspection.
I don’t know why people would lobby for less attic insulation though. Pretty much everyone is using either blown cellulose or blown fiberglass, and either allows very high levels of attic insulation for very low cost. It’s not a place where there is much money to be saved by cheaping out.
Bill
**Repost**Thank you all for all of your replies. A special thanks to Martin for digging into the Michigan code. I have supplied this to the builder already highlighting the applicable areas, although I didn't show the tub section, and the link to the DOE document to spell out the installation details to meet the requirements for them doesn't seem to be helping either. I think he is thinking this is something that he can "trade off". I tried to tell him that these are mandatory details (stated in the code) and would not apply to the prescriptive method. He kept saying that he could push up the blower door test, again I think he is missing the issue.
Bill, I had considered calling the state if I couldn't get anywhere with the builder or local official who is a private company contracted by the township as you have suggested, I think they have a 3rd party energy auditor that might be inspecting for some of these details, but I am not sure.
Peter, I did see that Michigan had changed the air tightness code to 4ach 50. Going through the building process has been frustrating to say the least. It seems like no one is on my side including the state with relaxing the code, inspectors not inspecting, and the builder for not supervising his subs. Through the process I have personally found and relayed huge mistakes to the builder from the trusses not being made correctly (no energy heel, with the builder saying he will add more insulation to make up for inadequately insulated top plates (yet to be verified, he refused to spray foam)--Michigan is also lax in it's attic insulation requirement going from R49 to R38 for climate zone 5, I did pay for the "upgrade" to R-49 though) to big holes in the WRB which I shimmied up a ladder and repaired myself before the cladding went on.
Where does the downgrade in code standards come from? Am I cynical to assume it is from the HBA lobby? I get that some change of the code is necessary or can even make sense given certain local variation, but I'm scratching my head on attic insulation and air tightness.
Again sorry for getting a little side tracked here, and thank you again to all.