I am considering using SIPs for my home design.  I want a very energy and cost effiecient building envelope system.

The house will be 1 story, 24' by 72', with a low pitch roof. 10' Cielings.   I think these dimensions lend themselves to modern building methods.

Are SIPS a better option than a steel frame with concrete decks?

No plumbing or electrical will have to run in the exterior walls.

I want a full foundation.

I am considering 24' steel trusses every 8 feet with SIP 4x8 panels spanning between them.

The north wall of the house will be buried if it is cost efficient.  ICF?  Pre-Cast? Suggestions? SIP treated as a roof? Has anyone built a berm wall agains a SIP wall?

Here are some rough renderings:
  

tlynch;

roof looks perfect for steel SIPs .........   for a list of advantages of steel SIP construction, please drop me an e mail

Chris,

Can steel SIPs be used below grade? I don't know much about them.

Jeff

I would think that for the roof OSB SIPS could easily be covered with a waterproof membrane, amd then a root barrier, then an irrigation layer, then soil, then sedum.

I am not sure why steel would be any different, although it may not give any benifit.

For the north wall, I am not sure if a berm wall is capable with SIPs, or if a concrete wall is needed.

Jeff; 
Iv'e never done it, but I know it's been done. I saw some job photos from Calgary;  a 2 story with full basement , balloon framed from footer to roof

Can OSB SIPS be used below grade? Wouldn't it be wisest to just extend the foundation wall? And use SIPS for the other three walls and roof?

Yes. Enercept makes both 'Foundation' panels and 'Basement' panels. The 'Foundation' panels can be completely buried, the 'Basement' panels can have the outside in earth contact(PT on the outside).

For your roof, with the high loading(and moisture & rot issues), you might be better off using concrete. Maybe economical & strong Hollow Core panels.

Then you're going to want to get rid of most of that window area. Costly and a huge energy drain.

I spent a while yesterday on AndersenWindows.com and saw how expensive large good windows are.

What is a good rule of thumb for percentage of total wall space that should be windows on the south wall - in the Northeast?

Obviously in winter months, during the day, windows can be a gain, and over the summer I would want as much circulation as possible, as I do not plan on having AC. So with proper thermal mass mght large windows on the south wall be efficient? (any suggested reading on this?)

In the NorthEast even southern exposure windows are a net loss daily from what Ive been told by HERs raters. The hours of sun in winter days here compared to the cold climate heat loss when the sun is down or its cloudy leave a loss in the end. Get good windows!
Mark

There is a view to the south, so I do want to keep some windows... so maybe not the MOST efficient...

Here it is with about 50% the previous number of windows.

Tlynch,

I do not know whether you are building in a subdivision or out in the country, but have you considered exterior insulated shutters over the windows? 

Building in the country - 5.6 acre lot. (although negotiations on the lot hit a major hurdle yesterday)

No, I had not, sounds interesting. Any links to read about them?

I had considered a think curtain (like a theater curtain) mounted on a track about 1 foot inside the windows that could be pulled all the way around the room.

Tlynch,

In the 70's when energy prices increased beyond reason, passive solar homes became stylish.  Insulated shutters were oftentimes used since the windows of that day had low R-values. 

In cold climates, interior insulated shutters can lead to the ice forming on the glass inside of the home.  Using an insulated shutter on the exterior keeps the window warm enough to prevent ice formation on the glass.

The best source that I have for thermal shutters is this book:  Thermal Shutters & Shades by William A. Shurcliff, 1980.

The problem with an interior curtain is that heat in the form of sunlight has already entered your building envelope through the window before it ever gets to the curtain (which would block some light but by then it's too late). The physical sunlight blocker should be on the exterior (like functional shutters).

I plan on having either an overhang or an awning to keep the high summer sun off of the windows. I was more concerned with the winter heat loss over night.

Alton - thanks, just ordered that book from an amazon associate.

- Todd

Steel SIP roofs can overhang eaves 4 feet without additional support

Todd, what are you using to render those pictures? And what part of the world did you say you were designing for?

I am using Google Sketchup, the free version, it is pretty intuitive.

http://sketchup.google.com/


My home is going to be located in Connecticut.

I posted this elsewhere - but I might as well post it here as well, because this is what it relates to:

Build a steel frame with 24' open steel trusses on 10' tall 4" H Beam posts, spaced 8' apart. Then use 8' x 4' OSB structural, insulated panels to enclose the envelope.

I think that the steel frame might cost around $14k and could be bolted together.

The 8x4 panels are $140 each. http://www.thesipstore.com/index.php?p=product&id=38&parent=0
Roof - 54 Panels - $7,500

Thinner panels for floor:
Floor - 54 Panels - $6,000

The 8x10 panels are $180 each. http://www.thesipstore.com/index.php?p=product&id=32&parent=18
Walls - 48 = $9,000

So $22,500 For SIPS. (I think this is a high estimate)

Foundation, full poured foundation - $15k.

Roofing - waterproof membrane, root barrier, drainage layer, Soil, sedum - Cost??

Siding - ?? Cost?

I would use 8'x8' sliding glass door to fill in roughly 9 of the bays - $1200 each = $11k on Windows. And reduce SIP cost a bit.

Frame $14k
Sips $22,500
Foundateion $15k.
Windows $11k
Roof - $15k??
Siding - $15k??
--------------------

So 92k in material for a complete green envelope for 1728 square feet. $53 per square foot.

I am considering replacing the full north wall with a concrete berm wall. This will reduce the SIP cost by roughly 18 panels 12', So roughly $3,200. And lower the siding cost. But the extra concrete work will be probably over $10k.