One of the builders I'm talking to said he's been looking into WallyWalls UltraFrame system. These might be classified as SIPs, though from my naive understanding they are certainly different than traditional SIPs. They are basically pre-fabbed frame+insulation. The insulation is graphite polystyrene (GPS), and the framing is steel. The steel doesn't run the full depth of the wall, so there should be no thermal bridging.

The website isn't the best, the "download our brochure" PDF has a more straightforward overview of the product.

It looks like it has a lot of benefits. But at this point I've only seen the manufacturer's information, which typically omits the negatives. :) I have for a long time been leaning towards ICF; this product appears to have many of the same benefits: mold/mildew resistance, insect resistance, sound dampening, high wind resistance, recyclable. One clear advantage over ICF is a much thinner wall for the same R-value; they claim an R-value of 5 per inch.

Just seeing if there's anyone out there who's familiar with this product. As I mentioned, the manufacturer's info makes it look pretty compelling, but I'm looking for the balanced perspective. Thanks!

There will be some thermal bridging, both through the studs and the top and bottom trim/tracks. I don't believe "99.9% effective thermal break" or R5 and they should publish a whole wall actual R value. "effective R-value of 33 with a 5 1/2 inch panel" is basically a lie; but the ICF companies also do this.

Steel and EPS are well proven. If you determine that the actual thermal performance is acceptable, then they might be a good choice.

There is another manufacturer with a similar product that uses steel C studs that do not go through the wall. The only pieces of steel that are in contact with the exterior and interior are the top and bottom plates like the Wally Wall. I have no affiliation with them. Been to the factory in Radford, VA and there is another company in Nevada (I think)that makes the same thing. It is ThermaSteel: http://www.thermasteelinc.com/ also https://hi-techbuilding.com/ Good luck with your project., Rich

WallyWalls are not a SIP, but rather pre-made sections of steel framing with insulation. They're claiming there is less steel in the web, therefore less thermal bridging than regular steel framing. That may be true, but enough to make an effective difference? Maybe not.

The steel studs do bridge from the inside to the exterior with Wally Walls.

Wannabuildgreen:
Did you/your builder go with Wally Walls? I just stumbled upon them today and am interested myself..
Thanks.

Posted By smartwall on 18 Sep 2016 11:03 AM
The steel studs do bridge from the inside to the exterior with Wally Walls.

When I was looking into these, what I was told was that they can be manufactured with extra foam that extends beyond the steel studs. The net result is similar to wrapping a traditional stick-frame house in a layer or two of rigid foam to break the thermal bridging. Again, that's just what I was told.

Posted By DP55412 on 17 Jun 2018 09:50 PM
Wannabuildgreen:
Did you/your builder go with Wally Walls? I just stumbled upon them today and am interested myself..
Thanks.

Unfortunately, I had to put my green building aspirations on hold. We were unable to find a lot in our target area, so were unable to do a custom build. I'm still interested in Wally Walls, though. The concept seems like a good idea. I'll definitely revisit this when I get the opportunity to build.

Does anyone know, when using a product like this, the house will not have traditional studs. So how are "heavy" things, like kitchen cabinets, mounted to the walls?

Screwed straight into the metal studs.
Or given some form of ledger board to spread the load across multiple studs.