hello!

First time posting in this thread, but I've been lurking here & the geothermal thread for a while.  I'm not sure if this is the right place for this question, but hopefully I'll get some responses.

My wife & I are building a house in 2010, hopefully breaking ground late spring.  We initially wanted to do SIP's but has since ruled them out  The main reason is that in our area I've only found one contractor that uses them, & subs generally aren't familiar with the technology.  I'm afraid that the lack of experience with the materials may cause some issues.

What we've decided to do instead is stick framing (2x6 exterior walls) with PU foam insulation.  I've heard some conflicting "tales" when it comes to insulation.  One method that is becoming more standard in our area (NE Wisconsin) is to spray foam an inch or so on exterior walls, then finish with R-19 batt, for R-24ish.  The idea is that the foam creates the air barrier, but keeps costs down.  5 1/2 inches of PU foam is in the neighborhood of R36-R40.  I've been told that this is overkill, and isn't worth the extra costs.  I've also been told that I can do 5 1/2 in of spray foam on the top & bottom 24 in, with 1 inch/batt in the rest of the cavity.

I don't want to do something that will give me no return on my investment, but at the same time, it's a one-shot deal.  No one tears out their walls to upgrade the insulation, you know?

Last question - I've read that one big advantage of SIP's is that the entire area of the wall is insulated, vs stick framing which has 1 1/2 in of "uninsulated" space at each stud.  I'm considering using some rigid foam insulation on the exterior instead of housewrap, to minimize that affect.   Again, not sure if it's worth the extra cost or if there are any downsides to that.

As I'm sure many of you know, talking to contractors can be frustrating, since many don't want to the job differently than they've done in the past.

Any suggestions?

yah the quadlock (www.quadlock.com) offers R-38. Will withstand anything. will last forever. Superstrong - superinsulated. problem solved.

Have you  priced the spray foam insulation yet . I thought about doing what you're doing for a while, until I realized how much spray foam cost. Also there are dew point issues to consider with the foam/ fiberglass system . You need to educate yourself about that . Are you too far along to reconsider SIPS?

So, Jerkylips, it looks to me like you posted on the SIP Forum because you still had some questions about this system, otherwise, you'd probably get more action on the "General Green Building" forums on this same website. There you will hear about countless ways to frame, insulate, and sheath, a building "envelope".

At this point I'm surprised that you haven't heard from some SIP guys in your area that are interested in your business. Actually, in my experience with SIPs, I don't think that I've ever seen an experienced, and "skilled" general contractor, or carpenter, who didn't catch on to SIPs once they allowed themselves to "look" at the system. Of course, i've seen some that just didn't want to "look"

Now, I'll start it off, if you would like to obtain more information regarding SIPs, and perhaps get a contractor referral, you might contact ACH Foam Technologies, a licensed AFM/R-Control manufacturer, who has a facility in Fond du Lac, Wisconsin.

Also, I assume that if you were to have any interest at all in ICF's, you would post your questions, or comments, in that regard, on the GBT ICF Forum, thus no comment here regarding that building system.

In any event, good luck with your project, whichever building materials that you decide to use.

Jerky,
Have to believe that, with all the different options you are considering, SIPS would not be your best choice.
SIPS have a small, and I mean SMALL, learning curve, for installers. The only other sub who should be affected, at all, would be your electrician. And every one that I have worked with has admitted afterward that his worries were unfounded.
Your other options involve several 'layers' of insulation protection. Each layer has the potential for failure, mostly thru flaws in installation technique. You are better off with one simple installation that accomplishes all that you seek.

Jerky,
If you want info from SIP manufacturers and Installers in your area, go to www.sips.org. The Structural Insulated Panel Association (SIPA) is the place to start. Fill out the info form with info to contact you, area you live in and what your looking for. Be prepared for a lot of responses. It's a great place to get info!

If you have questions about SIP's, feel free to ask.

Good luck!

John
PanelStar Custom Homes

thanks to all for the replies!

SIP was actually my first choice, but the more horror stories I've read, it scared me away. When I say horror stories, I'm strictly talking about the installation and using crews that are not familiar. I 100% believe in the technology, I just wish it was more popular in our area. I haven't ruled it out yet, just trying to do the research to make an informed decision.

One thing I have read has to do with costs assoc. with usings SIPs for roof panels - that it's not the most cost effective. I don't remember if I posted any details, but we're planning on building a ranch home in the neighborhood of 1900-2000 feet, with a vaulted ceiling in the living room. If we would go with SIPs, would it make sense to use the panels for the roof or use trusses? To me, it seems like you would want your best insulation properties in the roof, since you lose so much heat going up - that's why I was surprised to read that people use SIPs for the wall panels but not the roof..


Oh....someone asked about ICF's. From my research, it seems like SIP is a lot more bang for your buck when it comes to insulation. If I lived out west & was concerned about wildfires, etc., I'd probably go that route but in our area I think SIP's make more sense. Correct me if I'm wrong, please..

We are in a very moderate climate so we chose to use the insulated strand board  on the roof instead of SIPs(+15% R value). I did discover SIP walls are not as cost savings in construction as first told however  I am very please with the sound reduction and tolerance against moderate earth quakes..

If I was in the colder climates I would op'ed for SIP roofs ( if the  budget allowed for them, +$$$$ ).


Good Luck!

jerkylips
When designing sip/icf homes we use a combination of sips, icfs, raised heel trusses, etc. that best fits the design. You can use sips on just about any roof but scrap, higher ceilings, vaulted spaces not needed, underframing, etc. all go into the mix to decide whats best for a design besides the cost. Many of our sip/icf homes use a raised heel truss to get the extra insulation per code plus its easier to do vaults or cathedrals in needed spaces only. Typically trusses are always less and more practical than a sip roof unless its a shed type or if you want cathedral throughout the home. This varies with each design. If you have a sketch or a plan email to me and I would be glad to review and get back to you with your best options in my opinion.

I will take you up on that!  I have a jpg of a crude floorplan I created in visio - attached below.

The foyer/living room will have vaulted ceilings.  Kitchen will be 10 foot.  Bedrooms, not sure yet.  We're toying with the idea of doing a vaulted ceiling in the master instead of a tray ceiling (never been a big fan of those).  The image is not exactly to scale, but will be around 2000 sq feet & around 70 feet wide (including the garage)

Jerkylips, Your observation in regard to the advantages of using SIPs for Roofs is spot on. Just as with walls, a properly installed SIP roof system will virtually eliminate thermal shorts, and air leakage.
SIPs are particularly effective with designs that call for vaulted ceilings and/or conditioned attics.
However, having said that, SIPs may not be the best approach for very complex roof designs, with excessive hips, valleys, dormers, etc. Of course, where budget is a primary concern, you're likely going to keep your design as simple as possible anyway.

jerkylips
I will review and get you my opinion. I can post on this thread and or email to you directly.

Jerkylips, my last comments were submitted BEFORE you posted your sketch. However, I don't think that it would be very difficult to develop plans for a SIP building envelope (walls and roof) for a design such as this, with a little "fine tuning".

again, thanks to all!  I followed the sips.org link & actually found someone within about 15 miles of our city (only one close).  I spent about an hour on the phone with him & he alleviated many of my concerns.  My #1 concern was the electrical contractors - I've heard horror stories about channels being cut the wrong way in panels, foam being removed, etc.  He said that he has 3 contractors locally that he has personally trained on SIPs.  My other concern was that I've read no matter how good the panels are, if they are not installed correctly, you won't gain much efficiency over stick framing.  He is the supplier but also does the installation himself.  He said could do the excavation, including ICF's for the basement, the steel super-structure, & SIP installation, then let the general contractor take over from there.

Even though I wanted to do SIP construction, I had kind of ruled it out - this has definitely made me reconsider!!  Now I have to convince the wife - she is very conservative, & doesn't like to try "new" things.  Any suggestions on how to convince her?  She's not exactly a "numbers" person, so any other ideas would be welcome..


The SIP guy said one thing that I questioned, so I'd like to pose this question too.  He said that a typical 2x6 exterior wall with R19 bat yields a "whole wall" value of approx R13 because of the stud space & thermal bridging.  He uses insulspan panels, which are EPS vs urethane foam.  These panels are R24, so he's saying that you have basically double the R value.  Do these numbers sound correct?

Amazon sells Morley's SIP rbook "Structural Insulated Panels". Chapter 8 has ilus. and great ref's for wiring and plumbing.

We just finished our first SIP house, about 4000 Sf in Southern California. I bought this book for my GC and electrician, some dated info but a lot of very useful jump start stuff.

Careful who you use for drafting, SIPs and engineering, check them out very thoroughly!! Do not give them too much $$$ up front!!!! Lot of gypsy's and thieves out there!  

Thanks for the info, I'll check that book out - if nothing else, for my own info..

This guy mentioned something along the same lines, about drafting.  It's a family business, and his son, who is an engineer, does the plans.  He said we're welcome to have plans done anywhere, but they still need to load them into their system to figure out the connections between panels, the most efficient use of panels, etc.  I'm feeling good about this!!!

jerkylips
The plans you sent should have no issues for the sip walls.  The roof system
can be sip as well but I would not recommend it do to your intersecting gables from the rear, jogs and your multiple ceiling heights.  You would be better off structurally and cost by going to a raised heel truss which can accommodate your cathedrals and flat ceiling in the areas you want. 
Basically I would run your main roof left to right with a double gable off the rear covering the dining and porch.  Also a shed porch on the front would look nice as well.  As for the garage I would step it back 2' on the 3rd stall to give some detail to the front and to not have the garage overpower the main part of the home.    There are many minor issues with the sketch but all can be worked out in concept drawings.  If you would like a quote on doing the construction drawings let me know.  We have completed thousands of homes with many of those being sip construction or hybrid.  If you need any other input or have questions give me a call.
800-450-green

Jerky,
In one of your previous posts, you mentioned two reservations concerning SIPS.
1: The builder you spoke to talked about 'whole wall R value'. The numbers he mentioned are basically correct based on testing done by the Oak Ridge National Laboratories. A standard 2x6 stud wall with studs 24" on center and R19 fiberglass insulation has a rated R value of 13.69 by their testing methods. Most 6" SIPS are rated at about R24-25. So that statement is correct.
2: To convince your wife. You say the builder is only about 15 miles from you. See if he has any completed homes that you and your wife could visit I would guess that being in a SIPS home that is warm and comfortable, and seeing that the finished product is no different from what she is used to would allay any fears she might have. (It will also give you the opportunity to get the owners opinions of the builder.)
Good luck. I think that you will happy with your SIPS choice.

interesting that it's based on 24" OC.  In our area, code (as far as I know) is 16" OC.  I guess more studs would equal slightly lower R-value, right?

I like the idea of going through some of his homes.  I think my wife has it in her head that somehow SIPs = manufactured homes.  She made a comment like, "I don't want pre-made walls".  this guy seems to do a lot of high-end homes ($1M +, in some cases) (for those in SoCal, etc, that is a HUGE house in our area!!)  Maybe that's what I need to do, get her to associate SIPs with higher-end homes (not that we're building high-end, but that association can only help, right?)

I don't remember who posted the reply about not recommending SIPs for the roof panel - we haven't finalized the plan yet, specifically the ceiling heights, etc.  The only thing we know for sure is that we want a vaulted ceiling in the living room.  When talking to the SIP guy today, he said he really doesn't recommend using trusses with SIP walls, because you end up with the same issues of thermal bridging & reduced r-values that you worked so hard to eliminate in the walls.  I understand that he's a SIP guy so it's what I would expect him to say, but it makes sense.  Not sure if he's giving it more weight than it deserves, though..

Jerky,
Thermal bridging is not nearly as big an issue in roof structures as in walls.
The only time it really is a factor is if you use rafters only to create the vaulted ceiling you seek.
The design of the roof system should be a major determining factor in your decision of using SIPS or trusses. The more complex the roof system the harder it is to
use SIPS. I use SIPS in more straight forward (read simple) roof plans, but with the more complex systems, I prefer trusses and spray foam insulation on the underside of the roof sheathing. This creates an insulated, conditioned attic space (which I prefer) and eliminates the thermal bridging issue.