Introduction to Straw Bale Construction

AutoCAD File of the Workshop Building

The 14' x 10' building we will be building during this workshop was designed to be movable either by mounting it on a trailer or hoisting it using a boom truck.

The wooden deck consists of pressure treated 2x8s and plywood with a double perimeter beam and double load bearing beam under the inside plaster skin. All of the load bearing connections in the deck are reinforced with joist hangers. The insulated deck has a sheet of house wrap between the insulation and the bottom pressure treated plywood to allow moisture vapour to escape while preventing liquid water from getting in to the insulation. The deck has a sheet of vapour barrier between the insulation and the sub-floor plywood to prevent water vapour from inside the building from getting into the insulation. The deck is built upside down to allow the proper installation of the joist hangers, house wrap, and bottom plywood then flipped over and insulated before the vapour barrier and sub-floor plywood are installed. The 2x4 curb consists of an inside member installed 1" from the edge of the deck (to allow a 1" lip for the plaster to bear on) and an outside member installed the width of the bales away from the outside member (far edge to far edge) then the space between the members is filled with 1" thick Roxul Drain-Board.

The window and door bucks use plywood boxes to create the reveals and are installed on top of the curb. The walls are "edge stacked" (as opposed to "flat stacked") which produces a final nominal wall thickness of 16" ("flat stacking" produces a final nominal wall thickness of 21".) The thinner edge stacked walls provide much more usable floor space in a small building.

The top plate consists of a 2x4 ladder with 2x6s laminated to the inside and outside ladder members with plywood on the bottom of the 2x4 ladder and across the top of the 2x4 ladder and 2x6s. The corners are designed to overlap when installed to provide the greatest possible strength. The top plate is used to compress the walls before plastering. In a small building like this that is being plastered right away compression is unnecessary. We will be using polypropylene pallat strapping and steel wire buckles to compress the walls.

The windows and doors will be installed and weather sealed after the walls are compressed.

The roof will consist of a made-up center ridge beam consisting of 2x6s and plywood spacers supported by a pair of gable posts. The 2x6 roof rafters will be cut on-site and attached to the ridge beam with nails and to the top plate with hurricane ties. The gable ends will be stuffed with straw before the walls are stuffed, the mesh applied and the walls stitched.

We will be using a plaster of St. Lawrence Cement Mason's Choice High Bond Type N (which is 1 part cement and 1 part lime) to which we will add 3 parts (1:1:6) of sand. This plaster will be hauled up to and applied to the wall from a hawk using a trowel. We will apply two coats inside and out before the end of the weekend. Adventurous students are welcome to try their hand at straw sculpture by mixing hand fulls of straw with hand fulls of plaster and applying it by hand over the first coat of plaster. We may also create a candle niche in the straw before plastering the interior.

Schedule

Friday: (7:00 - 9:00) light refreshments will be served

Members of the congregation are invited to attend to meet the workshop participants.

- introductions
- site orientation
- safety briefing
- straw bale slide show
- introduction to load bearing construction
- overview of the workshop building

Saturday: (08:00 - 18:00)

- safety meeting
- curb
- stacking straw bales
- mesh
- stitching
- compression
- housekeeping

Sunday: (08:00 - 18:00)

- safety meeting
- detailing
- plaster
- housekeeping

Monday: (08:00 - 18:00)

- safety meeting
- plaster
- wrap up
- housekeeping

NOTE: Everyone MUST attend the safety meeting each day.

MEALS (Saturday, Sunday, and Monday) Menu

Breakfast - 08:00
The safety meeting will take place during breakfast.
Morning snack - 11:00
Lunch - 13:00
Afternoon snack - 15:00
Supper - 18:00 (or after quittin' time)

THINGS TO BRING to our workshops.

DIRECTIONS to Shanliwood Baptist Church and Hank and Anita's House.

ACCOMMODATIONS near Hank and Anita Carr's home and Shanliwood Baptist Church

RULES for all our workshops.

WEATHER for Spencerville, Ontario. Check it out before you come so you know what to expect.