Well done.

Quantum, let us know what you find out. I'm willing to change paths if it makes sense to do so. Thanks.

Walltech, why would you go vertical? I always "slick tape" all basements (I thought all joints had to have tape on them?). I think most, if not all tapers would rather have a seam at 4' tall around basement then a bunch of vertical seams? My hanger charges .15/sq ft to hang. I don't think he would do it cheaper if I told him he could hang vertically.

I never do ceilings unless requested by homeowner.

No, this was not an R-Value job nor was it from Arvid.

PS,.......I just realized one advantage of using no glue, and not taping joints would be finishing the basement later. The house I live in is all concrete. Had to drywall the basement. I actually applied finish coat of mud and then painted the entire basement. A year later, I put up some partitions in the basement to create some rooms. It would have been nice if all I had to do was take out a few screws to remove drywall from the icf to install electrical boxes!  The only other way to get around this is to use plastilock. It is impossible however, to predict where you will want boxes in the future.


Thks!!!
Bunt

 

 

Bunt, my points exactly. As you can imagine I have posted this scenario many times, and sometimes I get a little vague with my answers due to repeats. Yes this will require more tapping lineal footage in the future, but will allow you to pull a sheet here and there for the electrical plans down the road.

And no the IRC doesn't require it to be taped, even though your BI may say so. If he does (BI) claim it has to be taped, point out the use of ten other products that suffice as a 20min thermal barrier like wood sheathing and or Masonite and ask how you would tape and mud these.

Dave

Walltech,........understood and thank you!!

 

Bunt

I just got off the horn with the Air-Krete CEO, and have some new info.

It is possible to apply Air-Krete under roof rafters, but there are a few caveats:

- With foam insulation in the rafters they've found that over the years the heat buildup during Summer can cook the shingles and underlayment, shortening their life. So now it is recommended to have a venting material either on the deck or under it. I've seen this at recent building shows as a corregated plastic or coated corregated paper material that's installed so heat can travel through the tubes up the roof to the ridge vents. This would be advisable with Air-Krete as well as any foam in the rafters, although the problem wouldn't be so much in western WA where I am.

- Air-Krete can be installed under the deck in the attic, but it must be installed behind either a screen mesh or Tyvek. If the rafters are 2x6 this means that they must be firred out an additional 2.5" to give the 8" thickness of Air-Krete for Code-required R-31.

- I told him about teslastones' formulation which should allow application of 8" without the mesh or vapor barrier, but he was skeptical, saying that it may involve addition of acrylics or polmers which would cause smoke and emissions during a fire and/or VOCs. He says he is a purist, in that they only want inorganic materials in the product for fire safety. Maybe teslastones has an inorganic formulation, hopefully we'll find out.

- It seems that Air-Krete does in fact have the thermal mass I'd hoped for, which would smooth out the daily temperature fluctuations outside, as well as having the thermal resistance like foam, so this and its fire-resistance puts it head and shoulders above any foam.

And BTW Mac, open-cell foam will not seal a house air-tight. Air-tightness is needed to get a good score on the blower-door test, so this is why I had advocated 3" of closed-cell then the rest as open-cell to get R-31. But now I think Air-Krete is a far better solution if we can only eliminate the labor of firring out and meshing.

Keene does not know me by Teslastones but that is ok--it is how I want it.
It is good to hear that their new formulation is now fully inorganic. There was a time when mine was and theirs was not. Being listened to is nice.
I, also, am an advocate of ALL IN-organic and my stuff is and has always been.
For now I am content to just concentrate on the UK market. My only point in the original post was to tell you of an option to the issues related to using the foam products everyone seems to think are the only choices.
As to the "need" to furr the rafters, could one spray over the rafter using only a moving screed to ensure the needed depth?? If Airkrete is like my stuff it adheres very well and changing from 6" thick to 2" thick would not pose any problems.

I've seen three applicators of Air-Krete:
- A small hose;
- A vacuum-cleaner-like hose;
- and a hose with a box-fitting on it to help make a smoother application directly.

I was thinking why not use a vacuum-cleaner funnel attachment, like we've all used? It has a slight bend for attic work, and it would apply the material over a wider area, helping to finish it smoother.

I sometimes use a spray pattern irrigation head at the end of a 18mm dia. hose.  It lays out a nice strata that can be built up in subsequent layers (my formulation,not speaking for Airkrete's)

http://www.ornl.gov/sci/roofs+walls/AWT/ComputerSimulations/index.htm

Not to muddy the waters too much but, since you are interested in thermal mass and seem to uderstand the dynamics of such, look at the results of testing done at Oak Ridge concerning the inclusion of Phase Change Material.
When we put phase change material in the low density foam--or other strata such as wallboard---it makes the low density item respond like a high density item. Therefore you get the best of both worlds (the "R" value Americans want and the thermal flywheel and heat capacity dynamics understood by the rest of the world.)

Drywalling the underside of a 12 in 12 roof sounds like a nightmare to me. Isn't there some sort of fireproofing paint that can be sprayed on instead?

Quantum, with AirKrete, what exactly is the screen mesh/Tyvek for? I assume you meant the rafters would have to be furred out so that the mesh can be attached to them?

Whoah, phase-change materials... encapsulated calcium chloride hydrate... thermal capacitance. Kool. Although it adds $5/sqft. We do not really have hot roofs in western WA, as they do in Texas, so this may not be worth it. However the infrared-reflective paint on the standing-seam is interesting. I wonder how well it wears?

And the sprayer is a good idea, but am surprised the material flows through a smaller orifice. I guess I don't know alot about its properties yet. Seems like the control gets three inputs: high-density magnesium oxide slurry, blowing agent, and air. As the mag-oxide is blown you would get a great volume out for small volume in, so the hoses could be fairly small. A spray pattern would entrain further air for better R-value, and once the pattern is gotten right it would be quite efficient. Hm, I wonder about a modified airless spray rig? Maybe a screed 1-by every 4' or so for a neat job, and no damned mesh!

Jelly the fireproofing paint is what we were talking about above, with the Firegard and Contego. The mesh or Tyvek is to physically hold the Air-Krete in the cavity until it hardens, because its weight would overcome its adhesion otherwise. Yep the firring-out is solely to support the mesh or Tyvek. Keene now recommends Tyvek for it.

Quantum,
It is kool but more so than you may realize. What we are working with in UK is next generation PCM--not glaubers salt, calcium chloride, sodium sulphate etc.
THis is a microencapsulation of a phase change wax. It can be engineered to a specific reaction temperature within one degree C. Being an encapsulation there is no volumn change issues at the set point like with the old fashioned pcm.
Cost is about the same as bottled water which will be offset by the 40% energy savings
Keep your ear to the ground as this technology will filter into the US market within a year or two--a little birdie told me so

I saw the ORNL writeups on the encapsulated wax and its possible use in sheetrock, but I am very skeptical about its fire-resistance. An important job that sheetrock serves is as a fire barrier, in fact it's the only fire barrier here in most cases, conferring the 15 minutes required by Code. I can not imagine a fireproof wax, and so studied the calcium chloride hexahydrate. What's wrong with the latter besides cost? Haven't they improved its effectiveness 12x? WhyTH does hydrated calcium chloride cost so much? The encapsulation?

I do not know about the salt (cal. Chl) I can tell you the board with the phase change has a class B in UK. The only thing higher is concrete or glass. THe wallboard in UK has a class E
The US adopted the international fire code a couple of years ago ut it's implimentation has been delayed twice now as sheetrock cannot get close to the new requirements. My board will be a two hour rating by US standards. If you would like to see pictures of a 3,000 F flame on a half inch strata with no smoke or flame and the other side of the 12mm stays ambient for 30 minutes or more, let me know and I will send an attachment.
Uk does not have a fire station on every corner and is very strict about fireproof. 15 min. "resistance" is a joke.
As long as one can get insurance on unwise design there will be firewood construction in the US.

I'd like to see the photos please. How in the world is your sheetrock a two hour rating... with wax in it? Is it paper-faced? What's its composition?

And ya, agree that the EU is ten years ahead of us because we stopped investing in research 12 years ago.

Sorry I cannot reveal the formulation. It has NO paper face but it does have cellulose internally.
If you will email me at [email protected] I can attach pictures and test results to substantiate my wild claims.

Well, I am thoroughly sold on Air-Krete as insulation. There just needs to be a way to install it faster and easier, in order to bring the costs down which are substantial.

For what it's worth here's an email exchange I had this morning with a local guy who does energy audits for Energy Star certs. I believe he is also the only certified LEED auditor in Idaho at this time.

--------------------------------------------------------------------------
My question to him:

Txx,
Do you have any experience doing blower door tests on houses that
used Sealection 500 foam from Demilec? The local contractor is Fxx
Gxx Services. I'm planning on using it because it's the only foam
I can find that, with the Andek coating, has an ICC-ES report
allowing its use exposed in an attic space that is connected to the
living space.

In one of the discussion threads on GreenbuildingTalk.com one of the
posters says that Sealection will allow air to pass through readily
because it's an open cell foam and the house would have problems
passing a blower door test. This view is contrary to what I see on
the Sealection web site. That's why I'm interested in knowing what
your experience is with it.

----------------------------------------------------------------------------------------
His answer to me:

Yes, the foam can make an extremely tight home, you just need to pay
attention to completing the thermal boundary ( like an igloo) I would not
let them talk me into minimal insulation R-values vs. air sealing
advantages. Other than that they are great.

----------------------------------------------------------------------------------

Based on T's caution, I take it this contractor likes to try and convince people they don't need all the recommended R-value of insulation because the foam is so air tight. I guess that's one way to sell foam based on price!

Nah; open-cell is not air-tight, but it is more air-restrictive than batt... which is not saying much. Remember, there's a magnitude of difference between Stick-tight and ICF-tight; I suspect your certifier is used to thinking in terms of stick.

Closed-cell is air-tight, but both open- and closed- have fire-rating restrictions on thickness.

Is this teslastones or tesla was right?