What about settling?  I agree with everything you said about cellulose but had ruled it out because of settling issues.  I figured that no matter how good the insulation, a 2" gap at the top of your wall where there is NO insulation will probably outweigh the rest.

Off topic, but dang, Jerky here is our house, looks very close to yours.

http://www.uwgb.edu/nevermab/pic/house.jpg

The front side is facing north.

I guess so!!

I seem to remember from a previous post that your house is bigger than what we're doing but I could be wrong.

Also, when we were talking about passive solar, I remember you saying that you get a lot of heat on the south side in the winter - but it doesn't look like you have a ton of windows (on the first floor, at least).

I was planning to get some pretty significant window-age on the back/south side to take advantage of that sun, but now you have me worried about overdoing it...

The main floor is listed as 2100 sq ft and yes on the main floor it is mainly the kitchen / dining area with the three big ones. The kitchen has a regular windows towards the big windows and then the small glass block like window under the cabinets that you can sort of see in the drawings. The master bedroom is the one missing windows on the bump out. Personally I was trying to avoid windows since I figured over the winter we would lose more heat out them than we can gain from sun coming back in. Although my wife and the builders had a minimum numbers of windows for given spaces. :)

"a 2" gap at the top of your wall where there is NO insulation will probably outweigh the rest" It sure will. The basic reason cellulose is "dense packed" is that is they have figured out that when blown at 3.5#/SF it does not settle. In the "old" days it was mostly used on sidewalls in retrofits where they would drill a round hole, insert the hose & fill the bay. That did settle. Anyone familiar with using cellulose above flat ceiilings has seen it settle - when you want 12" they better install 15" (+/-) as that's what you'll end up with. But if its is dense packed into a limited size bay, it will not settle. That is why I said it needs to be installed by a quality oriented professional - the HD rental machine won't do the job.

good info to know, thanks for sharing!  From what I've heard, cellulose does a better job with sound deadening, too.

curious, do you know how this compares to the blown in blanket fiberglass stuff? 

I do not. R value should be similar. Back before the "green" revolution one insulating company near me priced it competitive to spray foam; they probably have come down some but I haven't seen any reason to use it when cellulose is so available.

I take it from your response that the dense pack cellulose is cheaper than that?  My builder used the blown in blanket with 1" spray foam in the stud cavities & said it was an upcharge of about $2000 over just the R19 batts (for a 1900 sq ft house)

A local spray foam contarctor charges $1.00 per board foot, so the $2000 sounds about right. I meant if all things are equal I'd use the recycled & greener product. If you have strong preference for a quality installer that uses the fiberglass, that would be a reason to use that product. My costs for insulation have gone up dramatically since I stopped using fiberglass batts, but so has the performance of the houses I'm building. Most builders around here have traditionally used "commodity" insulators who slap it in the walls fast, but getting high performance out of any insulation requires that it be done with care by people who know what they are doing.

Fiberglass batts don't give you an air seal, but you can accomplish that in other less expensive fashions than spray foam, such as huber's ZIP system. Also, faced batts stapled in place properly do not settle, unless something puts so much force on them that they actually pull out all the staples. In my limited 4-5 years of construction experience, I have never had a batt that didn't properly fit a cavity, and if I had I would have removed it and gone another route for that cavity. Batts are 1/2" larger than the cavity they are designed to go into, and if your studs are over 1/2" off, you've got bigger problems than insulation gaps. Bob_I is absolutely right about the insulators that rush and screw up a batt job, but that is the fault of the installer, not the product. I admit that there are many better insulation products than fiberglass batts, but the additional cost could better be spent elsewhere. Trust me, there is always a better product or system, but you always have to look for where your best bang for the buck is.

Going back to the equation I shared yesterday,

R-19 batt =U- 0.0526, R-5.5 stud=U- 0.181818,
85%*.0526+15%*0.181818=U-0.07198=R-13.89.

Even if we were to insulate this wall cavity space in the best way possible, using 5.5" of closed cell spray foam at R-7 per inch,
Foam 5.5"*7=R38.5 U=0.025974. 
85%*.025974+15%*0.181818=U-.05207=R-19.2.

So we can see that increasing the R value of what is in the cavity from R-19 batts to 38.5 foam only increased the R value of the wall assembly by R-5.3. However, anything you add to the continuous layer of foam on the outside, you will get the full benefit. Upgrading from 2" polyiso foam to 3" polyiso foam for example would give you the full R-7, which is actually more benefit than filling the entire 2*6 bay with closed cell spray foam which only netted a R-5.3.
I would be much more concerned about the continuous layer of foam on the outside than what I put in the bays.

Thats the thing about R values, small areas of very low R value punish the rest of the area. For example, you can have your whole ceiling insulated to R-100, but if you add a 2'*4' uninsulated attic access door with R-1 (as so many builders around here love to do), on a 1000 sf house, the R value of the whole ceiling would drop to
992/1000*1/100+8/1000*1/1=U-0.01792=R-55.8, which is almost in half! Thermal bridging really kills!

Edit: By around here, I meant where I live (Tennessee), not the members of this forum. I don't think members of this forum would put in an access hatch without insulating it somehow.

The problem with relying on one surface, like ZIP sheathing to eliminate infiltartion is that there are numerous places air can get inside a wall. We all know that 2x4's are not perfect and each irregularity at the top, bottom and each side will admit air. The best way to minimze infiltration is to fill the cavity with a material that minimizes the movement of air. Fiberglass batts are not such a material.

I don't understand how air will get into a wall when the sheathing is a continuous layer over the 2*4's, all the seams are taped, and all penetrations are caulked or foamed. Irregularity in framing members won't let air in when the air can't even get to the framing members to begin with. I have worked on four houses (and one garage) using the zip system, and I have never felt any drafts coming through the walls. I know no system is ever perfect, but there isn't going to be much air moving past any vapor retarder with seams taped and penetrations caulked. Using spray foam might be a better additional air seal than fiberglass batts, but we are talking about taking it from 0.01 cfm to 0.001 cfm, which is essentially useless when you think about having to run a 20cfm fan through an erv anyway to keep fresh air inside your house. Also, think about the air leaks from having imperfect door seals and dryer vents, they are going to be way than any wall with a continuous vapor retarder with taped seams and caulked penetrations. That being said, if you plan to do a crappy job on the zip system, or you plan to not tape the joints, or you plan to not caulk the penetrations, then it might be a good idea to spend a lot more money on a cavity insulation that also blocks the movement of air. Personally, I would invest a few extra dollars and hours to make sure that one system is done right, and then not have to pay out the nose for an insulation that does what another system should have been doing for you to begin with.

So, Jerkylips, this is not to bash any of these mostly well articulated "Alternatives to SIPs", but why not just build with SIPs? I made my case in a fairly lengthy post on this thread (1/1/'10 at 4:41PM) Since then there have been no arguments to any of my comments, just numerous rather complicated approaches aimed at achieving a similar level of energy efficiency.

Again, good luck with your "search"!

We haven't ruled it out yet.  In fact, I talked to our builder today.  He asked me a while ago if I had any resources/documentation I could give him so that he could at least start to get familiar with the product.  After looking at what I sent him, he said today he has no concerns about putting them up.  At this point it's just a matter of cost.  If I can get the project (including hvac, etc.) with sips to come in close to stick framed, we are going to. 

Some of my reasoning for asking about alternatives was to make sure that when comparing prices, I'm comparing apples to apples.  I guarantee that a 2x6 r19 wall will be cheaper, but it's not really a fair comparison..

Fair enough! However, I'm sure that you know by now that a 2 x 6 frame wall with R-19 insulation in the stud bays only gives you about an R-11 full wall R-Value (U.S. Dept of Energy ORNL report)Its the extra steps and materials required to try to equal the energy efficiency (R-Value + Air tightness) of SIPs that typically gives you your "apples to apples" cost comparison.

By the way, did you and your builder check out the R-Control website as one of your "resources?

I realize that many of us "industry types" often repeat ourselves, but, since there's a constant flow of new visitors to these forums,
I think that this is an acceptable practice.

Sipper -- if you need help understanding why the best building one can produce is ICF with a SIPS roof I will be glad to assist.

Hey, Texas ICF, I appreciate your offer to enlighten me but you're "preaching to the choir". If you'll peruse the threads in the ICF Forum on this website you'll see that I'm a big believer in exactly what you're advocating, ICF walls, and SIP roofs. However, if you were paying attention you'd know that BUDGET is a primary issue with the instigator of this thread.

Now maybe in Texas (my home state by the way) you can put up an ICF wall that is comparable to a SIP wall in energy efficiency (and, don't start talking about "thermal mass") for the same price, but I doubt that you can come close in Wisconsin where he's building. I know that you can't in California where I am.

Having said that I'm well aware that there are some ICF systems that offer the option of thicker foam on either, or both, sides, TF the original "Vertical" ICF system for one (Plug) as well some of the "blocks". However, this approach does add some additional expense, not only for the walls themselves but for the additional material required for doors, windows, top plates, etc. (6", 8", 10" of concrete + 5" to 6", or more, of foam? You do the math. As I've said before, I love to see ICFS in Hurricane or Tornado country, and for projects where cost is not a primary issue, or concrete is dirt cheap, or labor is cheap or free,or,or..

Now, I'd still like to see Jerkylips try to go with SIP walls and roof and an ICF (TF?) basement if he can make the numbers work.

By the way, Texas ICF, that was too bad about Colt McCoy last night (a sincere comment)...... but...........GO COWBOYS!

Jerkylips,

Now that you have a preliminary plan, have someone run some heat load calculations between SIP and stick frame. You should have this done regardless when sizing your HVAC, and get HVAC estimates for SIP route and stick frame. Sounds like you plan on using a poured foundation w/ 2" rigid foam on the outside regardless if you go SIP or stick frame (I suggest also getting an estimate for Superior Walls). The roof truss, make sure you get a raised heel, about 12", so you get more attic insulation between the exterior walls and roof sheathing.

If you go with SIP, are you looking at 6" or 8" thick?

If you go with stick frame, will you do 2x4 or 2x6 w/ 2" rigid foam on the exterior? Spray foam insulation or spray in cellulose in the wall cavity? You could also look into a 2x4 staggered stud configuration, 6" top and bottom plates, w/ 2" rigid foam exterior (2x4's are cheap)

When it comes to insulation and wall thicknesses, there is a point of diminishing return. If certain wall advertises a R-84 (Quad-Lock ICF) and your heat load calculation determines that a wall with a much lower r value will have only slightly lower performance, then you would never see a return on investment in energy savings with the more expensive R-84 wall. That is why I suggest having heat load calculations done, on the options that you are considering, to help you determine what is best for you and will still be within your total cost to build AND cost to operate & maintain.

Jere

There is a system that I like (but I have never actually built one) that uses a grid of 2"x2" with the insulation between the 2x2s.  This minimizes the bridging of this wooden grid that supports the insulation and the exterior sheathing or siding.   The following is  a discussion of this type of construction using cellulose insulation but I would think this could be used just as well with foam board cut to fit between the 2x2s (as I was thinking of doing) or even bats.   This would solve the problem of supporting the exterior siding when using thick exterior insulation.
http://www.builditsolar.com/Projects/Conservation/MooneyWall/MooneyWall.htm

Sipper -- I will send you a private message so as to not clutter things up here. I am quite interested in a couple of the points you made. thanks.