posted 6 years ago
Hi Greg, Good to hear from you!
Greg is referring to a commercial building project in down town Eugene, OR, that is now completed. The Mahonia building is about a city block in size, and three stories high (only the top two stories are straw bale; part of the first floor is under ground). Designed by Arkin-Tilt Architects in Berkeley, CA, the straw bales were stacked as part of a CASBA workshop back in...2017? It has exterior plywood sheathing and metal siding, and a clay plastered interior. The 3-string wheat straw bales were stacked "on end" between paired 2 x 6 "posts" set on 24" centers, but for some reason not all of the 2 x 6s were on 24" centers so we had to do a lot of bale slicing. Necessity being the mother of invention, David Arkin designed a bale slicing jig that we adapted and fussed with until we could shave inches off a bale in under 50 seconds using an electric chain saw.
Fun project! That building detail--bales on end--made it into the book, too--it's in Chapter 2 Designing with Straw Bales.
Back to your project.
I think you want to avoid custom trimming each bale unless you make a bale slicing jig like we had in Eugene. Find out what your bale size is. We used 3-string bales in Eugene because the bales we pulled from the Willamette Valley happened to be about 23” wide, so with studs on “mostly” 24” centers it was tight squeeze to force/pop them into place. I thought they were pretty tight, without much need to stuff gaps between.
I liked the method we used on the Mahonia building to secure the bales to the wall—long timber screws and plywood washers. Bamboo stakes could also work to secure the bales to one another, although I’m not clear on how that secures the bales to the framing? If you haven’t already installed the exterior sheathing you might tie the bales into the framing with baling twine.
As for baling needles, there’s a side bar in Chapter 4 Stacking Straw Bale Walls on how to make one from ¼” welding rod and a propane torch, hammer, drill, and file. Or you might search the internet. Lydia Doleman, Flying Hammer Productions (www.theflyinghammer.com) a local colleague and expert on both straw bale and light straw clay construction (see her book Essential Light Straw Clay Construction by New Society Publishers) sells baling needles—have usually have a few at every job site.
Good luck!