Raycore(6"panels) is one of the products I am looking at for my new house construction in MN. Siding will be mostly stucco and some stone/brick. What would be the best way to assemble the exterior to minimize thermal bridging and moisture issues? Thanks

I'm not too familiar with Raycore systems, but it seems to me that if you're going to go with the 5.5" panel I would get the one that has the studs 16" O.C. From the website, it looks like they alternate the 2X4 studs which gives a layer of foam on the side compared to the 24" O.C. panel which features 2X6 studs all the way through. The 16" O.C. panel with 2X4 studs would help eliminate thermal bridging in itself. The only question now is when it comes to the top and bottom plate, and door and window bucks. This would be where most of your thermal bridging would occur. If it's in your budget, perhaps it would be best to add another layer of foam on the outside of the house, at least in these areas. Or you could go with Zip-R sheathing featuring an inch of foam under 7/16" OSB. It's your continuous layer of foam and sheathing all in one. I believe it also has a vapor barrier built in so it may or may not be the way to go since you live in a cold region.

As far as moisture goes, I'm not too familiar on brands but I believe you would want to put your air barrier and vapor retarder on the inside surface of the panels-which continues my thought on why Zip sheathing with its built-in vapor barrier may not be the best idea. I think code minimum is 6 mil plastic sheet. Don't quote me on this though. I'm not very familiar with building in cold regions. The pros on here will have better advice on moisture control in your region. Hope some of this is helpful.

Raycore is made with closed cell polyurethane foam- they're pretty robust from moisture issues compared to other wall systems.

But since that foam is blown with high global warming potential HFC245fa (more than 1000x CO2) it may not ever break even on environmental damage over the lifecycle of the product if going with the 6 inchers.

Polyisocyanurate and expanded polystyrene are blown with pentane (at 7x CO2 gwp), and are by far greener products. A 4" layer of polyiso on the outside of the sheathign of 2x6 batt insulated stick built would perform comparably to a 6" RayCore SIP (lower center-cavity R notwithstanding) at much lower damage.

Staggered-stud stick built using Icynene's 2.2.lb or 2.0lb water blown foams (MD-R-210 or MD-R-200) would give you comparable R and better air sealing at about 0.1% of the global warming damage of the RayCore system.

Thanks for the replies.

HVAC,
I have considered similar assembly as to what you are suggesting, using ZIP R sheathing . Any idea as to what the cost of ZIP R sheathing is?

Dana,
I appreciate your reply. I have read about your concerns regarding closed cell PU previously as well. At this point, I am just in the investigating stage, looking at different systems, ICF, SIPS, stick construction etc. My hunch is that I will end up going with SIPs(sandwich panels). However, I want to do the due diligence to research the heck out of everything. I am researching the cost, construction details, ease of construction, timeframe, r-value, "greenness" etc. In the end, it will be combination of these factors. But like I said, my goal is to learn as much as I can, so I am able to make an informed decision.

I haven't called about Zip Sheathing because I am not using it in my design. I am going with ICF for the thermal performance as well as the strength as I am in Tornado Alley. If you are considering ICF I would highly recommend it. After the research I've done for my area, they are very reasonably priced and very DIY friendly. Dana actually pointed me toward asymmetrical ICF forms (Nudura,Quad-Lock, and others I'm sure) and I am designing to take advantage of the thermal mass of the concrete.

SIPs are very excellent performance wise and steel SIPs are crazy simple and durable. I haven't priced those yet either but I will be sure to let you know when I find out. I plan to roof my house with them to have cathedral ceilings. ICFs and SIPs are hands-down the best in my opinion to build a green, efficient, comfortable home.

I was not aware about Raycore. I cam to know it after reading this post. I am in the process of renovating my house. Can I use it now?
JenniferBuysHouses

What's the scope of your renovation project?

Interesting conversation

Who is the best SIP manufacture out there?

Frank, i have toured the plant at Extreme Panel, Cottonwood MN and seen their work. I think they do a very good job. I recomend them for roofs and cantilevered walls other walls should be ICF.

Timberwolf, I am located in MN. If /when there was a better wall system than ICFs, I would be using it.

Posted By ICFconstruction on 18 Oct 2013 10:15 PM
Frank, i have toured the plant at Extreme Panel, Cottonwood MN and seen their work. I think they do a very good job. I recomend them for roofs and cantilevered walls other walls should be ICF.

Timberwolf, I am located in MN. If /when there was a better wall system than ICFs, I would be using it.

ICFconstruction, You are preaching to the choir. I had a house plan done by a designer for a full ICF house. Paid over $30,000 for it. Unfortunately, our family business got a huge hit and we were pretty much dead in the water. We are starting from scratch with some savings(no construction loan) and will start building a downsized(and a LOT less expensive) house. I will have to consider a combination of less expensive options(e.g. stick vs ICF) and doing some of the work myself to achieve the goal.

Sounds like me. Built my own house without a construction loan. Very few comforts when we moved in, the plastic over the openings kept us up at night, flapping in the wind. Still don't have, trim, paint, kitchen cabinets or a garage floor, but it is ICF, can't compromise on that.

ICF walls should add only 3-5% to the build cost, cut corners on something else that you can replace later, like flooring, cabinets. Or just leave something out until you can finish it. ICFs are forgiving that way, I have only a base coat of synthetic stucco on the exterior.

I agree. I am still going through all possible scenarios in my mind. But we have been living in a house for 6 year that we were going to tear down after we bought it. We have had 2 kids since we started planning for the house and now the older one is going to kindergarten. Another year of construction and then living in an unfinished house for who knows how long(am sure finances will permit finishing for a while)? And there are other personal reasons to have a finished house soon.

I am still considering ICF and will definitely use it for the basement. For the whole house though, 2 things will have to happen. I know the contractors won't like to hear that but it's just a financial reality for us. A DIY job doing all the non-concrete work working with a consultant who would do all the concrete work(pour, flatwork). And getting a reasonable bid for synthetic stucco - lot lower than what I have gotten and are usually as much as 3 coat stucco. Admittedly, so far I have only talked to a couple stucco contractors about synthetic on ICF and I could tell they didn't have much experience with that.

Funny, I also I have two, one just started kindergarten, 5 and almost 3 years old, boys. I told my wife that anyone could have a finished house to move into, but then the one-time thrill is over, for us every time I get something done there is a thrill.....She doesn't buy it, but there is some truth to it.

We do synthetic stucco too, and I would recommend you do that yourself. It is easier, requires less specialty equipment and there is no hurry to get it done. It doesn't require "skill" like traditional stucco. Versus the ICF walls you want up quickly, there is much more to know and expensive bracing (rent or own).

Once up, stick framing is not as DIY friendly because if you get a roof, wall, window or door leak because you didn't get to something or screwed up, you could have a serious problem. Take my case, I have only a base coat of synthetic stucco, no window detail, with wind driven rain it has leaked to the inside, twice. No problem though, nothing to damage, no wood framing or cavity or wall insulation that would be damaged.

I am in Minnetrista, you should come check it out.

Funny indeed as mine are 5 and 3 as well, they are girls though.

Even funnier is that I live in Orono, right on the edge bordering Minnetrista. I will see if I can make my out there some day.

We did a foundation for the PBS TV show Hometime, they are still working on it. Just south of Watertown road on Brown Road. turn on creek ridge pass.