These panels are made with two layers of oriented strand board (OSB) sheathing glued to a core of expanded polystyrene (EPS) or polyurethane foam.  (photo or section detail of SIPS) The R-value of the panels varies with the thickness and the type of foam used and can be as high as R-49.  Perhaps as important as the R-value is the fact that, when properly installed, SIPS create a very tight shell around a frame with little or no air-infiltration or thermal bridging.  Much like timberframes, SIPS can be fabricated in a controlled shop environment and delivered to the building site ready to install around the frame.  That combination makes it possible to raise and enclose a 3000 SF timberframe home in just a week or so of good weather, any time of year.  That translates into big benefits for most projects including reduced schedule, overhead, and exposure to bad weather.  It’s easy to design and engineer a home to be enclosed with SIPS because they have been thoroughly tested for both gravity and lateral load resistance.  Panels make strong shear walls which helps make very durable homes.

Some drawbacks to building with SIPS are they are made from petroleum products which are sure to become more expensive; they are large and costly to ship to remote job sites; and most OSB sheathing contains formaldehyde.  For more information on enclosing timberframes with SIPS see Tedd Benson’s excellent book, “The Timberframe Home.”

Another option to enclose timberframes is by using straw bales to create an 18” thick wall with an R-value of up to 60.  Straw bale construction has only been around as long as baling machines, or just over 100 years, but in that time has been used to create some remarkably beautiful and energy efficient buildings.  The benefits of building with bales include the high R-value; the good use of a renewable agricultural waste product; the low cost of material; and the aesthetic appeal of thick, sculptural walls with natural plaster finishes.  The primary drawback to building with bales is they are susceptible to mold or fungal growth if they are exposed to water and not thoroughly dried.  That can be a problem during construction when they must be kept dry until they are plastered and throughout the life of the structure when it is necessary to diligently maintain the roof, plaster and flashing details.  For an in-depth look at building with straw bales consider “Serious Strawbale” by Michel Bergeron and Paul Lacinski.  Here are some photos of timberframe-straw bale houses we have built.  (Insert photos of Johnson and Stanley-Charette.)

Our favorite way to enclose a timberframe is with a 12” thick monolithic wall of compacted clay and straw.  Clay and straw have been used to build walls for thousands of years all around the world.  Similar recipes have been used to create adobe bricks, cobb walls and wattle-and-daub, the local building materials of many different cultures.  In a timberframe context, perhaps the best known examples are the English Tudor-style homes, Japanese temples or the German lechtlehmbau (straw light clay buildings).  Some of these homes have been continuously occupied for over 800 years.

The benefits of building with clay-straw walls include: the use of natural, local, healthy, bio-degradable, inexpensive materials.  The walls provide good R-value (approx. R-25) and great thermal mass and the walls are vapor permeable.  All of these characteristics combine to improve indoor air quality and keep the temperature and humidity of the building comfortable and constant.  Most of all, clay-straw walls are beautiful.

The modern proponents of building with clay and straw in North America are Robert Laporte and Paula Baker-Laporte of the Econest Company.  You can learn more about this excellent building system at www.econest.com or in their book, “Econest.”  Teton Timberframe is proud to be the Econest affiliates for Wyoming and Idaho.

There are many compelling reasons to build timberframes including durability, energy efficiency, beauty and use of renewable materials.  Timberframe construction is appropriate for a wide variety of structures including homes, barns, lodges, churches and temples, commercial buildings, porches, gazebos, and greenhouses

Timberframe Advantage#1:

• Timberframe construction has withstood the test of time.  There are many timberframe buildings that have been continually occupied for hundreds of years and with proper maintenance, they will last for hundreds more.  They perform very well under the high snow loads of Europe and North America and the high seismic loads in Japan and California.

Sadly, more than half of the homes built in America since World War II have already been torn down.  (National Association of Home Builders)  The vast majority of these homes was stud-framed and didn’t last as long as a 30 year mortgage.

Build a timberframe to have a conversation with future generations about beautiful, renewable buildings.