Air Barrier vs. Insulation

I have been teaching this insulation air barrier stuff for a few months now, something I never thought I would.

Never-the-less it is the "next thing."

As we understand more about how thermal, air and moisture barriers work there will be many changes in the way we build.

Historically as we moved from living in structures with fire pits to computer-designed hvac systems we neglected the other parts of the structure.

Eureka! House as a System!

I am still working on how to best convey this concept.

Remember when we began to regularly put insulation in buildings and discovered there needed to be a moisture barrier on the inside?
Then everyone did it, an didn't didn't work in all climates.

Now we know that insulation needs an air barrier to work.

We have heard for years that fg insulation needs to be in contact with a solid surface on all six sides in a wall to be effective and now we are wondering how that works in a horizontal application, floors and ceilings.

The federally-funded weatherization initiate which benefitted from a huge infusion is leading the way.

These folks have been at it for nearly 40 years and now with enough money and some great [url=http://waptac.org/WAP-Training-Centers/WAP-Network-Verified.aspx]training centers[/url] the word is getting out.

FYI, I do this training at the [url=http://www.lacapinc.org/]Louisiana Training Center.[/url]

So check [url=http://www.waptac.org/]it out.[/url]

I predict this will slowly be integrated into the regular building practice and since builders are slow to change I will always have a job.

Thanks for the opp.

[QUOTE=Bill Robinson;595749]Builders are slow to change I will always have a job.

Thanks for the opp.[/QUOTE]

Yes you will always have a job. Builders are motivated by getting to the closing table and walking away with a check that hopefully pays off their loans and leaves a small single digit profit. It is hard to worry about saving the planet when you are worried about making next months interest payment.

[QUOTE=Ted S.;595747]
SPF is over-rated and knowledge is under-rated in my opinion.[/QUOTE]

Well put, Ted.

[QUOTE=Allan Edwards;595750]Yes you will always have a job. Builders are motivated by getting to the closing table and walking away with a check that hopefully pays off their loans and leaves a small single digit profit. It is hard to worry about saving the planet when you are worried about making next moths interest payment.[/QUOTE]



Now you have done it, watch where this thread goes now.

Spoken like a true-dat builder Allan.

Maybe construction is the last place a boy can continue recess.

No classroom, no studying and the rules are loosely enforced.

It is play time.

My contractor mentor is cousin Jerry, he has passed but will be forever be remembered for saying "I want I doin' it, I not want to I not doin' it.
A true contractor if I ever saw one.

Jerry never wore a seat belt and died of cancer smoking until the last day he could draw breath.

Is it about saving the planet or something closer to home?

IMO, no matter what we do the planet will survive, maybe not the way we know it but it will survive.

It seems this all began in earnest in 1973 when OPEC decided to limit oil exports with the intent of punishing us for getting involved in mid east political affairs.

From that our response was the DOE, energy codes, and much of what we see now intended to reduce energy consumption.
And a lot of political stuff.

I do not believe the initial intent was to save the planet, just to keep control of our dependance on foreign energy/oil.
If you look at the data we have not done a very good job.

I apologize for taking the bait.

Thanks Bill Robinson,
I like the link you posted for the Louisianna Training Center
thanks

[QUOTE=Allan Edwards;595734]
What I am asking is what are the various methods and materials used to create an air barrier from a 2nd floor to a non-conditioned, vented attic. Something that is reasonably easy, affordable, and works on large houses with varying plate heights, groin ceilings, semi-vaulted ceings. Don't think of a 30' x 80' rectangular building, that's easy. Think of a 10,000 sq ft home with all kind of offsets, raises, bumps, vaults, 2 story ceilings, etc.[/QUOTE]

Just as insulation, vapor retarders, and air barriers have to be designed to work together as a system, the architectural process will have to include that design. Designing a structure that can't easily be constructed isn't much different from designing one that can't easily be insulated, be airtight, and be protected from moisture damage over time.

[QUOTE=Bill Robinson;595749]We have heard for years that fg insulation needs to be in contact with a solid surface on all six sides in a wall to be effective and now we are wondering how that works in a horizontal application, floors and ceilings.[/QUOTE]

The word I got from the top of the food chain is they they most absolutely would like to see both the attic and framed floor assemblies also have the 6 sided air barrier and that their reasoning not to do it is because it is almost prohibitive to do in mainstream construction, the target of many of these programs.

It's nice to know that even our leaders can be reasonable (RRP excluded).

Dick, surely you're not suggesting that we control the owner's desire to have some bling?

Pull-up covers over fg have been long proven to[url=http://www.homeenergy.org/archive/hem.dis.anl.gov/eehem/92/920510.html] counter[/url] the effects of convective currents.

I've been using sprayed cellulose in attics since '89, which avoids the problem altogether.

[QUOTE=David Meiland;595769]Dick, surely you're not suggesting that we control the owner's desire to have some bling?[/QUOTE]

Have you hugged [i]your[/i] Fonthill Abbey today?

[QUOTE=David Meiland;595769]Dick, surely you're not suggesting that we control the owner's desire to have some bling?[/QUOTE]

Without the bling, they aren't buying. Without buyers, I'm not building.

What is the best air barrier for an attic floor.

I think it would help, in your situation Allan, to be more clear what you mean by an attic floor.

Most attics are not designed to have a floor.

If it is used for storage the joist system should be designed for the additional load.

Yes, many people add a floor for neat storage, is that what you mean?

In general the best air barrier would be one that is easily made continuos and connected to the air barriered wall.

Sheets, 4' x 8' say, sealed at seams and penetrations, the back side of the finished ceiling, the drywall or plaster in most cases, is only waiting for the seams and penetrations to be sealed. That is pretty much the standard and easily accomplished in new construction.

No reason to make it complicated.

[QUOTE=Bill Robinson;595792]Sheets, 4' x 8' say, sealed at seams and penetrations, the back side of the finished ceiling, the drywall or plaster in most cases, is only waiting for the seams and penetrations to be sealed. That is pretty much the standard and easily accomplished in new construction.

No reason to make it complicated.[/QUOTE]

So you think the drywall on a ceiling can be a sufficient air barrier.

It is the standard when sealed at joints and penetrations, yep!