Building the Cabin at Straw Hollow

We decided that our cabin would sit on a slab of concrete, so we we dug a hole and filled it with gravel for drainage.

Using 1 x 6 boards as concrete forms, we did our best to make sure everything was square and level. We placed rigid foam insulation and plastic vapour barrier within the forms, then we called the concrete truck. Twenty-four hours later, we removed the forms, and the job was done. Easy!

Before we laid the foundation, we decided to use threaded rod as a straw bale tie-down system, so before the concrete dried, we set bolts at evenly spaced intervals around the perimeter of the foundation to anchor the bottom end of the rods.

We used pressure treated wood to build a toe-up which raises the bales by an inch or two, helping prevent spills or floods from soaking into the walls.

We placed rigid foam insulation within the toe-up, and secured tar paper on top, to prevent moisture wicking up from below. We constructed and installed door and window bucks to allow for straight, even openings in the walls.

The final step in this stage of construction was the building and installation of temporary corner braces.

Now we're building with straw!

It's important to make sure that the bales are firmly stacked in a "running bond" to ensure strength and stability. It's not rocket science, but it pays to take things slow and easy to avoid bulges and gaps in the walls. With each couple of rows, we screwed another series of threaded rods into place.

After the final course of bales, we built a wooden top plate, through which the top ends of the threaded rods were placed.

With nuts and washers on the threaded rod, we compressed the bales by an average of three or four inches all around, giving us four firm, even walls of equal height.

Pre-compression of the bales allows the roof to be added without fear of further settling, which could cause cracked walls, broken windows and a crooked roof.

Often the most difficult task for the novice builder is roofing... we started this task with only the vaguest idea of how to proceed. We recommend that anyone approaching this task might want to read a roofing book first. After some discussion and wasted lumber, we ended up with a sturdy waterproof roof with 45 degree pitch. The roof sheathing is 3/4 inch aspenite. We stapled tar paper to the aspenite as a moisture barrier.

We had salvaged some steel roofing from a structure that had previously stood on Straw Hollow. We attached this steel to the roof, using rubber-gasket screws, then we temporarily wrapped the cabin in a breathable house wrap, allowing the walls to stay dry, and preventing mould or mildew buildup in the bales until the exterior cement stucco could be applied.

The first layer of cement stucco is called the scratch coat. We used a mix of two parts cement, one part lime and five parts sand. We reinforced the door and window areas with diamond lathe. Chicken wire was "sewn" to the bales with twine and a metre long bale needle. The scratch coat is the thickest coat of stucco. In the space of one afternoon, our friends had the job done. And all they asked in return was pizza and beer.

Thanks to our dedicated group of friends, the brown coat was applied the following day. The brown coat has a slightly higher sand content. We made a two-piece "barn door" and installed a prefab window. The door looks great and fits the rustic theme of the cabin.

Later, we added two coats of stucco to the inside of the cabin, so at this point, any critters who might have made their home in our bales are forever entombed.

The third layer of stucco was a thin colour coat. Having attached diamond lathe to the gable ends of the cabin, the stucco now reaches all the way to the peak of the roof. We added pigment to the mix to add some warm colour to the stucco. The interior of the cabin has a nice smooth, sponged finish, accentuating the subtle (and some not-so-subtle) curves.

On the ceiling, we installed OSB (oriented strand board) on top of a good thick layer of "Roxul" brand insulation. There's no point having highly insulative walls if the roof is not insulated too. We caulked any remaining cracks in the woodwork, and then painted the ceiling.

Outside, we primed the roof (which due to its recycled nature, originally came in several shades of grey), then painted it Tremclad green. We added, and painted, soffits and facia to finish the roof structure, then nailed in metal eavestroughs and downspouts, complete with rain barrel for water collection.

The concrete floor of the cabin was finished with plywood, then stained and varnished. We added our "truth window" ... a small frame, attached to a small un-stucco-ed area of wall, through which any doubting visitor can see the straw "inside" the walls. Although we didn't "wire" the cabin, we located a GFCI protected 110v electrical socket located just outside the door.