I'm in the very early stages of building design for a retirement home in Northern New Mexico.  Elevation is 8900 ft, high heating degree days, no cooling days.  I have pretty well decided to use either SIPS or composite (Rastra) for construction.  I would sub out the roof, but plan on doing mosst of the rest of the structural construction myself.  ( I have built a couple homes in the past so I know my way around a site). 

There are points in favor of each.  Rastra - manufacturing point is 3 hours away, plant manager is a contractor himself and he has a crew that I could hire should I decide to offload some of the work by that time.  The inside is plaster-ready, the exterior is stucco/stone ready.  As the exterior may be exposed for a time while I construct, and the sun at that latitude and elevation is strong, I'm afraid regular ICF would degrade and require substantial rasping, and of course the wire and all to stucco. 

Disadvantage? How good is Rastra at high heating loads?  You've got to assume the ORNL report that your thermal mass doubles the R value. (please let's not get into R-value thread), But this concerns me. 

Sips would actually be used in conjunction with Rastra.  Two lower floors are into a hillside (rastra).  Two upper floors are above grade (SIPS).  (You got to see what I have to contend with for elevations, but the view is spectacular.)  Value of this method? Less mass to support.  Could build with 10" foam and really have a super insulated house.

Disadvantage - Sheetrock all walls, more exterior prep, electrical is more difficult (in my mind) especially if changes are made after the SIPS arrive or are in place.  AND the issue of sound transmission.  There are two snow makers 100 feet from where the house will be located.  There was a thread about sound transmission a while back in one of the forums.  Unfortunately views presented were at both ends of the spectrum.

How easy is it to pump concrete 4 stories, more actually with eaves?  What about the sound of a snow maker? Rastra efficiency in cold (winter) climate? Problems combining the two?  Running electrical in SIPS compared to ICF?  Any other thoughts?

Thanks in advance for any comments.

Dunno if you have looked at the other possibilities that are manufactured in or near Phoenix: Apex block ( www.apexconsys.com ) has the same cement/EPS mix/waffle grid concrete core as Rastra. (Probably no accident.) Also E-Crete ( www.e-crete.com ) makes blocks of aerated autoclaved concrete, or the European approach to low density concrete. Highway sound barriers are made of AAC, which tells you something.
You'd be silly not to consider passive solar where you are building, assuming you can group your windows facing south. If you can, any of high-mass approaches above would be winners. UCLA's Climate Consultant 4 will tell you all you need to know about your weather and walk you through the design choices. http://www2.aud.ucla.edu/energy-design-tools/ Also look at www.builditsolar.com for other ways to put all that sun to work for you.
Thermal mass by itself works best where there are big swings in daily temperature around an average you'd consider comfortable. While Denver is the closest approximation in Rastra's simulations, you are almost 4,000 feet higher....

LarryT,
Since you mentioned composite systems also, you might want to check out the Saebi system from Glendale AZ.  I do not sell any products but I do have more info about this new system.  My e-mail address is below.

Larry T & Alton at auburn dot edu

While Saebi has a VERY good system, don't go to them for a 'onesy' deal. They are only interested in talking to folks who want to build an entire subdivision, etc. They won't give the time of day to someone who wants to build just one home. Time will tell - they may get hungry!!

If Saebi has that attitude, then there is not much chance that they will be around long.  Do they not realize how difficult it is to get a new building system accepted and used by the average builder.  Just because a company has code approval does not mean that it will be accepted by the public.

As far as the system goes, I would not hesitate to use it since the math makes sense to me.  My only hope of using this system is to find a builder that is already licensed.  The typical owner/builder should not have to buy a license to use their system.

Since I retired from teaching in the School of Architecture at Auburn University in 2004, I have been donating my time to owner/builders that I have met through this forum.  Feel free to e-mail me.  I will reply as time and interest permits.

By the way, I write my e-mail address the way I do to keep "bots" from capturing it and spamming me to death.

I have also been looking at a composite ICF because the plant (Amazon) is one hour away from where I will build (hot/humid near gulf coast), so I probably have more of a water concern than you do.

My view is that if I use this product, I will add an extra layer of exterior insulation and create a drainage plane behind the stucco.  Composite ICF needs to be detailed (from a water standpoint) as a CMU...it is porous, and in my location I want a belt and suspenders.  For me, relying on stucco as the only water barrier is a bit risky.  If I were using conventional ICF, I would want "lopsided" (i.e., thicker insulation on the exterior) forms or extra insulation on standard forms,  probably still with the drainage plane.

I am not a big believer in ICF thermal mass benefit, but I think you are in a place where you will get some benefit, at least for a good part of the year.  You should introduce more interior thermal mass (floors?) if you want to benefit from passive solar.  Intuitively, seems that composite ICF may have more "interior" thermal mass benefit than a standard form, but that is a guess.

Technically, pumping concrete any distance is not a big problem, but is really dependent on local equipment and concrete mix.

I have never looked at the acoustical differences between SIPS or ICF, but the acoustical weak points will likely be the doors, windows and details.  It would be useful to get some sound readings of the snow making machines at your site before they shut down for the season.  My guess is that you will need acoustically improved windows, at least for sleeping areas......expensive.

No matter if you use SIPS or ICF, you will have a lot of scaffold to deal with.  It sounds like your site is 30% or steeper.  Be sure to think through the construction logistics.


Bruce

Alton, I guess you worked with Samuel Mockbee at the Rural Studio some. That man was one of my heros. Anyone not familiar with the Rural Studio should google it. Both of the books i have about it are awesome and had a huge impact on my project. Great resources for green building. Makes me wish i was an architect. Were you involved in any of the Rural studios projects that i may have seen? Thanks Michael

Brawler,

Sambo was a great colleague in the School of Architecture here at Auburn University.  We miss him now that he is gone.  He was a gifted architect and had a heart of gold for helping the poor into homes they would never have had otherwise.  He was an inspiration for our students and faculty.

Although I worked at the main campus here in Auburn, I knew Sambo well.  I helped train many an architectural student in computer graphics before they went for their hands-on training under Sambo at the Rural Studio.

Even to this day, I am amazed of how many people have heard of Sambo and his Rural Studio.

Todd, Thanks for the links.

I'm definitely considering passive solar as the axis of the House is East-West, so large area facing south.  The gain will be offset in part by a window wall on the north side, but passive will definitely will be a feature.  I've been a fan of passive since the 70's. (Showing my age)

Alton and Todd, thanks for the leads on the other manufacturers.  I'll see what they have.  Manufacturers in the SW are certainly what I'm looking for.  I have seen ECO Block ICF's used a lot in the area, but again am leaning toward composite.

There was a thread that was in the ICF secction 6-8 weeks ago which mentioned Millenium Block.  I was in the Denver area and decided to drive to Colorado Springs to see them, without calling ahead.  Address turned out to be a P.O. Box only.  Area code of phone was Atlanta.  Kinda leaves you wondering what support one could expect.  Anyone use Millenium?  where are they made?

Fortunately, water is not going to be a huge thing to worry about where I am at, but having two stories partially subterranean, means I still have to pay attention to is from several standpoints, grading, waterproofing, drainage plane for those two stories.

I too have thought about lopsided block and that's why I was interested in Millenium as they say they make an assymetric ICF.

And when I think about adding extra layer of foam either inside or out, I'm thinking maybe SIPS are the answer as I've now lost an advantage of direct stucco/plaster. 

Logistics are definitely on my mind.  Site access is very good from one side, with the drive already in.  I had heavy equipment in, demo-ing a cored CMU structure that was built and never finished.  Now that only gets me easy access to one side, or two stories worth.  Thereby my question about how high vertically can one expect to pump 4 stories.  A lot of hydraulic weight.  It may be possible to come down the ski slope itself with a concrete truck or crane to better access the upper stories when they are underway.  The ski slope is not too bad, maybe 7-10% and has road access about 200 yards up.  The whole thing will be a bit of a challenge and yes, I'd better get a long term rental on a lot of scaffolding!

Sound insulating windoes sound like something to look into, especially for the master.  Although my wife might like the change of sound from my snoring!

Thanks to all for your help

This will seem obvious but I will state it anyway.  When having ready-mix concrete delivered up a steep grade, you may have to have a reduced load.  I also have found it useful to use a truck with the discharge in front so concrete will not spill out the back on a steep grade.  I know these things are small details but it can make or break your day when everything else is going awry.

I like composite ICFs, however to have two levels below grade maybe tough. Composite ICFs are post and beam, therefore may lack the strength to withstand backfill pressure of two stories, depending on soil type and ceiling height.

Wow I hadn't even thought about the post and beam nature of composites and below grade loads.  Definitely something to ask the manufacturers now, and confirm with the engineer when I get further along.  I could possibly load up on steel.  One of the nice things I was counting on was the reduced volume of concrete in the composite blocks.  Many thanks for the thought. 

What is obvious to one can be completely missed by someone else.  It's the little things missed that really ruin one's day!  Discussion with the local suppliers will be in order.

The thickness of the structural portion of the wall and its reinforcing have more to do with its structural capacity than whether it is a solid wall or a grid wall. 

Think of it as a flat slab vs. a waffle slab tilted on edge.  Deflection is generally goverened by the structural thickness.  Having said that, I know there are more thickness choices with conventional forms than with composite forms.

Do consult with an engineer, however.  Also, if you have high passive soil pressures or the possibility of hydrostatic pressure (You probably don't if you are excavating rock) on one side, then you may have to deal with an unbalanced load situation.  You don't want you home sliding down the mountain.

Bruce

Bruce, I have never built with a composite ICF or any other screen grid ICF. So I based my post on the 2006 IRC Table R404.4(5) for screen grid ICFs. The table allows for only 5' of backfill with a 9' ceiling and a middle of the road soil class. And that is with a 12" on center post and beam design, and composite ICFs are 15" or 16".

Larry, I really like composite ICFs you should do regular ICFs below grade and a composite ICF above grade. I met with the Steve of Cempo and he built a two story office at his place, years ago and never put anything over the outside of the composite ICFs and they were holding up fine.

Your 2 story point is very real and may (depending on soil conditions) even push to a conventional cast in place concrete wall.

Mine was only that I would not expect to see a significant structural difference between a standard ICF form and a composite form with the same structural thickness.   It seems that it should be possible to reinforce a standard form more heavily than a composite, however.

Bruce

ICF/Bruce,

All good information. I'm glad I posted. I can start now to work out a solution instead of later on. Even more complicated as the first floor will be 14' high (garage with lift, workshop). Second level probably 9'. I could tie it into the hillside, but probably easier other ways.

Thanks everyone. Time to regroup.

Larry,

I'm building with "Millenium Block" right now.  Mine is the same stuff that's made down the road from you.  Here's what I know of the situation.  As Rastra continues the stumble around in the ICF business, it's past partners, associates, etc., tend to spin off similar businesses.  Eterna Block in Pima, AZ was affiliated with Rastra, but no more.  Millenium Block came up with a little twist on the grid-screen block idea and is in Colorado.  I ordered my block from Millenium, and it was shipped from Pima (after some delay).  When I said "hey, this is Rastra," I got the story.  Millenium Block's 12" blockis made by them in CO.  Millenium Block's 10" block is Eterna Block, which was Rastra Block.

Anyway, as to the product.  It's use in below grade unbalanced backfill situations is going to be difficult because it only allows rebar to be placed 15" on center.  Most codes give required rebar schedules in 12" oc increments.  I'm not sure how comfortable a building inspector or engineer would be if you go very far outside the "norm" with a grid system that limits placement to 15" increments.  If you space out your rebar two verticals to a post, then the rebar isn't uniformly encased and that will likely complicate the engineering beyond where the engineer is comfortable.   If you have to go above #5 bar, then you're going to be getting custom cuts or using a torch.  It gets complicated very fast.

Because of a construction delay,  I've had my house exposed with no siding or interior finish all winter here in the temperate rain forests of Western Washington.  For Easter, we got 2 inches of driving rain.  I've yet to see any water come through the ICF, though I know it drained through when the blocks were stacked before building began.  Driving rain hits my gable ends (also poured ICF block) despite the 24" eave, and drains down the second floor wall (past and around windows) and down the first floor wall (past and around windows).  I have a slab on grade first floor, so if water came in, I'd see it.  So far, with many days of hard rain, nothing.  Once I get it stuccoed directly to the block (no drainage plane), I also don't expect to see a drop of water.

Pictures at http://dewattohouse.blogspot.com/

Mark