The outside of the library after the color coat - it just blends in with the rest of the house

The straw bale library is now pretty much indistinguishable from the rest of the house, except for its very very thick walls. The exterior was finished much as the rest of the house was finished.  First there was a scratch coat (although this one was thicker than elsewhere in the house to account for the (surprisingly small) unevenness in the straw.  Then the brown coat and the color coat were applied exactly the same as it was elsewhere on the house.

The scratch coat inside the straw bale library

The scratch coat inside the straw bale library

Inside, the straw got a structolite “scratch coat” which is a light weight, but very hard plaster.  That coat was then followed by a smooth plaster coat.  The final coat will unify the plastered straw bale walls with the drywall in the upper soffit and ceiling.

the library window seat after the smooth plaster coat


Exterior View of Strawbale and Window

It has been a long time between blog posts, but there will be a few catchup.  Catherine has been spending her weekends finishing up all the detailing on the straw bale library interior.  We left the exterior finishing to the experts because it has to be waterproof!

Bamboo is tied through the bales to lock them in place, courtesy of “Boa Constructor”.

After the bale raising party, there is still plenty of work to be done before you have a finished bale room.  The walls of rough bales need to be completely locked into place, and to have their surfaces prepped for the final finishes (stucco on the outside, plaster on the inside).

Locking the bales in place to the foundation starts with the “imbalers” or pieces of rebar that were embedded in the foundation onto which the first row of bales were placed.  The sill plates also have 10d nails in them that act like velcro on the underside of the bales.  Between the sill plates,  the bed for the first row of bales also includes a layer of gravel to allow drainage should (heaven forbid!) any water ever get inside the bale wall.  The key to the longevity and structural integrity of a strawbale construction is keeping the water out!


Lots of details on top of the first course of bales

Side view of bale courses

As the walls were built, the bales were notched into the wooden frame, and the corners were locked together with alternating bales at the corners (like brick laying), and then further locked in with large rebar “staples” that were pounded in on each layer.  On the first row of bales, the electrical wiring is also run to electrical boxes for outlets around the room.  Old-school strawbale construction has you pounding rebar pins vertically down through the stack of bales to tie them together, but for in-fill construction, this is difficult because you have a roof in place above your walls.  Instead, the bale walls are locked together with bamboo poles on the inside and outside that are tied through the wall and tightened to make the bale walls monolithic structures.The top row of bales are held in place on the outside wall by an exterior beam that runs around the perimeter of the room.  The top row of bales is then notched and “persuaded” into place against this beam which prevents them from falling out.  These details were all complete on the day of the bale raising, then the process of completing the walls on the interior began.

2×4’s for the bookshelves

Deep windows

The final step for locking the walls in to place, is to use a chainsaw to notch the bales at regular intervals around the interior wall so that vertical 2x4s can be installed to lock the bales in on the inside.  (Standing on a ladder, cutting straw with a chainsaw is fun for about 10 minutes.)  These vertical 2x4s (which visible in the pictures at right with green spray paint on them – all these pictures can be opened to see larger versions) not only help prevent the bale wall from toppling into the room during an earthquake, but they also provide mounting points to help prevent bookshelves from toppling in an earthquake (this is, after all, the library).  In addition, they provide the internal framing for attaching the lath needed for completing the window details.

When finished, straw is tightly packed under the lath

Catherine pounding in straw!

Window and interior wall finishing is a bit more like sculpture than carpentry – that is, if your preferred media are straw and expanded metal lath.  To take the raw end of strawbales, and make them into a smooth firm surface that can be a finished plastered surface, you need to staple metal lath next to the window opening, then bend it around and staple it to the interior 2×4. You then proceed to ram loose straw into this uneven space with improvised tools until you have a nicely finished curved opening to the window that can be plastered, and won’t crack if you then lean against it.  This is especially important in the large window seat!

The window area — ready for plaster

Close-up of the straw packed in

The main interior walls are a bit easier as they are already relatively smooth.  Once you have found and filled in all the little chinks and gaps in the straw at the top of the bales and around the edges, you can attach lath over the entire surface.  There is some interesting constructs like corner keepers to make out of various types of lath.  Several weekends were spent fabricating all the details and installing them with about 2000 staples to keep everything in place.  Now the entire room is finally trued up, nicely finished and has a surface ready for plastering.  Whew!

Close-up of corner

View from the front

Stacks o’ bales

This post is coming a bit after the bale raising for a couple of reasons – one we’ve been crazy busy, and the other is we were very disheartened by the fact that most of our photos of the bale raising are gone in the digital camera equivalent of opening up the back of the camera with film in it.  There was some weird format error on our card, and fewer than 1 in 10 of the photos from the incredibly fun bale raising are still readable…. sigh

We are trying to get photos from some of the other folks who were there, and if we can, we’ll put up a much more extensive set of photos, but until then… we’ll steel ourselves and blog on with the few remaining photos…

Michele, of Boa Constructor shows us how to work the bales

On a fortuitously sunny Saturday November 21st, an intrepid crew of friends and volunteers interested in straw bale construction arrived for our Mohr Family Bale raising.  The plan is to turn the pile of straw bales (not hay!) into a well-built and sturdy walls for our library.  The goal: deep window seats and high insulation value.

Few people there had any straw bale building experience, but Michele Landegger from Boa Constructor, and Dohnyat, the local straw bale expert, soon turned our rag tag band of surgical robot engineers and straw bale enthusiasts into a crack straw bale construction team.   Michele and Dohnyat are shown at right demonstrating how to notch a straw bale so that it could be fit around the vertical post of the moment frame.  This is a technique that we would use over and over as we cut, re-tied, wedged, and stomped those bales into a precision line.

Dhonyat, of Boa Constructor was the super-bale-expert

As with anything, the key is to have the right tools!  We had bale saws which are like very large knives with big smooth serrations.  You slice the straw more than “sawing” like wood.  There are also bale needles which are like enormous sewing machine needles that you use to thread baling twine through to re- tie a bale into a smaller “custom” bale [no pics of the needle, :-(  but a re-tied bale can be seen] and special “reference” 2x4s to check straightness of the walls as they go up.

But, hands down, everyone’s favorite tool is “the persuader” a delicate, high-precision tool for gently moving those bales into position.

Meg, Ely, and David “persuade” a bale

Everyone loved The Persuader

After 8 hours of measuring, marking, cutting, tying, hauling, placing, shoving, kicking, stomping and persuading, we had raised the walls, and an exhausted and straw covered crew opened some beers, started the grill, and kicked back for the first official party of the new house… it was outside, around a fire pit, and we sat on straw bales and ate off paper plates – but it counts!


and congratulations to what Michele called “the best Straw bale crew I’ve ever worked with”

Amy, Andrew, Arjang, Charlotte, David, David, Dean, Dohnyat, Don, Elymarie, Emily, Forrest, Greg, Jerry, Jennifer, John, Meg, Michele, Mike, Nick, Pamela, Paul, Randy, Suzanne, Thomas, Tom

(and to the kids who so nicely played all day in the back and let the mommies and daddies work!)

Come get hands-on, physical and dusty!  Learn about straw bale building while helping us build the straw bale walls for our library. We will be trimming, notching & stacking the straw bales that make the exterior walls of our superinsulated library.  We’ll supply the bales and tools… but bring gloves if you have them.

Kids are welcome, we have a play structure in the back, mounds of dirt, and lots of sharp objects lying around from construction (just kidding, we’ll rake everything up before the bale raising).  We’ll have supervision for the kids in the back and middle yards, and have art projects, and other activities for them to do.  We will, of course, feed you and we’ll all have a big BBQ at the end with plenty of beer!

RSVP with number of adults and kids (with ages) so we can plan food and activities accordingly.