Saturday, June 23, 2012

Learning from Swedish Home Building - Part 4

Today we published a new video in our series about Learning from Swedish Home Building, this time about the Rockford Swedish Standard House that I visited back in March, 2012. This house has a very interesting background story. Its the product of a circumstances that probably had a one in a billion chance of aligning with the research Scott Hedges and I were doing on Swedish House building techniques. But there it was, right in the heartland of the USA, somebody was building a Swedish house.

This project will continue in the Fall of 2012 when the schools' academic years begin again, and we will follow up with more information about its progress then. But in the meantime, this video introduction to the project includes more footage I shot when I was there.

This video piece is about a house in Rockford Illinois being built by a team of American High School Students and visiting Swedish Vocational School Students. They are building a Swedish wall system using American materials that is very similar to the prototypes laid out in our USA New Wall. The USA New Wall is our recommendation for applying Swedish building techniques to American home building.

The walls in this Rockford house will have approximately R35 worth of insulation in them when done. Two layers of 1.5" stone wool at approximately R6 each, and the main stud space with 5.5" or stone wool at R23. The furred layering on both sides will reduce thermal bridging and improve the averaged R value performance of the wall.

This Project is the result of a unique economic development relationship between Rockford, and Swedish sister city Lidköping. It is being built as an effort of the Swedish American Foundation of the Rockford Swedish American Health System which is engaged in urban renewal in the neighborhoods surrounding the hospital. The Swedish American Foundation sponsors teams of students from the Construction Program at De la Gardiegymnasiet, a trade school from Lidköping. Together with the students from Rockford East High School, and under the coordination of East High School Instructor Matt Walling the house is constructed on a site a few blocks from the hospital.

We have more background on this project here including a detailed analysis of the wall system they are using:

As recommended for the USA New Wall, the Swedish Standard house shown in this video will use use Stone Wool insulation rather than fiberglass. You can read a detailed article about why we prefer Stone Wool on our blog:

You can read the entire Letters from Sweden series on our blog which tracks our research and applications of into blog post's into Swedish House building, and its application in the US:

The USA New Wall, and Swedish Platform Framing are an outgrowth of our research into Swedish building practices. Again, you can find details of the USA New Wall here:

And Swedish Platform Framing here:

If you need assistance implementing the USA New Wall or Swedish Platform Framing in your projects, we are here to help. Please contact us.


  1. Greg, with the horiz. strapping on the interior, does the drywall also get installed horizontally? Traditionally we run it vertically since the long edges are tapered, i.e. butt joints are tough to mud & tape nicely.

  2. I think you would go horizontal. When drywall goes right on the studs you would put it vertical, so the joints were supported along the stud.

    I think here you do the same thing, put the drywall horizontal so the joint falls along the furring.

  3. Greg,

    A few questions:

    1) Do the 2x2 furring strips provide enough nailing surface for horizontal drywall? It seems to be cutting it close. Wouldn't a standard 2x4 provide a bit more wiggle room?

    2) With the furring, how are switch boxes and outlet boxes attached so that the vapor barrier remains intact?

    3) In the video, the OSB was already attached to the outer wall furring. How do they plan to install the rockwool into that space? I've seen this product at IBS and it's totally rigid. I can't see how they plan to place that insulation after the fact.

  4. Kent,

    The 2x2 have a 1.5" face just like a wall stud, so making a drywall joint on the furring is no different than conventional practices today. Nailing the drywall is probably not so good, the furring would be bouncy. But everybody screws these days so its absolutely fine.

    I covered electrical boxes in another blog post, but its simple. You have to use square boxes with a switch/outlet adapter cover. You just screw the box to the face of the stud, or off the side to a furring strip. If you go to the face of the stud, yes, that screw makes a hole in the vapor retarder - as did the staples used to put it up..

    Yes, at the Rockford House they will have to cut that first layer of insulation into 24" pieces to make it easier to install from the inside - a compromise for having the sheathing in place. The only alternative is to put that layer up before the sheathing goes on, which means you have to mix your trades. There is definitely a sequence issue here with the Rockford wall - and I discussed this in the blog post on the Rockford house visit (the first of the links above). But it gains the sheathing right at the exterior which means there is no struggling with american style windows - they can be mounted conventionally with nailing fins. And the default american vinyl siding can go right over it. Face it - no energy efficient wall system is going to take hold in America if you can't easily mount our windows and vinyl siding to it.

  5. Greg,

    Thanks for the reply. I had missed the original article somehow. Perhaps what we really need to solve the "sheathing" problem is a little out of the box thinking. Technically speaking, the dense rockwool panel is insulation, but mechanically, it goes up much more like OSB with its inherent rigidity. To me, the simplest solution would be to convince framers to install the rockwool, in much the same way they do regular paneling. In this way, the only adjustment needed is for the insulation contractor to arrange delivery of the material to the site. The convenience of window nailing to OSB would be preserved.

    I find that contractors are typically tradition bound, but can be convinced to work in new ways when the benefits are obvious.

  6. The exterior sheathing rock wool is very rigid, more so than the 1.5" batts they will use here. But as you say even these 1.5" rock wool batts are much more rigid than fiberglass.

    Ideally the carpenters would put it up as they did the sheathing. Small builders that do their own carpentry and insulation - this is a natural. For builders that rely on subcontractors for these trades, they will have a tougher time convincing their subs to stray from the norm. They'll get over charged because the sub won't have a good idea how long it will take. This is someplace a smaller builder with a flexible workforce has an advantage.

  7. Hey Greg,

    Quick question for ya. I've been following your posts on Swedish construction for a while now and I really like what I see. It all makes sense but I would like to know how does this kind of construction (and similar construction methods in Germany) would stand up to earthquakes? Specially large ones? Does the Japanese construction method Sekisuihouse uses for their Shawood homes, using precut post and beam elements that bolt together have an advantage?

  8. There is no problem meeting the bracing requirements of the current code with these walls. The code offers several different options and most are compatible with these Swedish inspired wall systems. If you are in a seismic zone, you should have the help of an engineer. The engineer will make specific recommendations on how to meet the code requirements of a seismic zone. These reinforcements would be the same for these walls as normal stud construction.

    I've seen these Japanese timber frame connectors before but I have no experience with them. I would not expect it to be affordable, nor easy to find a contractor familiar with working with them.