Window and Door Bucks in a Straw Bale Load Bearing House
When making window and door bucks for your load bearing home or other structure, you have a few choices to make.
What size wood do you want to use?
What design should you employ?
How will you attach the bucks to the wall?
I find that knowing the answers to these questions BEFORE I start building is more than important; it is imperative. If I do not know the details of the structure before I start, I am sure to run into hang ups along the way well beyond the normal hurdles that we all encounter when building.
For me, the design of the buck comes first. By creating a design, I can easily answer the other two questions.
In some cases, I will design a buck with angle side walls to ease the flaring of the window wells. in other situations, I will anchor the windows and doors with flat, simple bucks. In fact, I know what design I will use based on the utility of the window well. If the window will double as a seat, I am more likely to use a flat design to allow people to sit comfortably in the well. If not, I will use a flared well to bring more light into the room.
In either case, a flat or angled buck, I double the door design so that a uniform look runs through the house. In addition, I use plywood for most of my bucks, whether angled or flat, to give extra nailing for the mesh. The plywood extensions on the structural framing cut down on dimensional lumber and increase the ability to anchor the mesh to the bucks as noted above.
The advantage of using larger structural members is in anchoring the buck to the wall. With a deeper unit, say a 2x10 instead of a 2x4 with plywood, the dowel that is later driven into the bales goes through more "meaty" wood.
The deeper the wood member, the further towards the center of the bale you can get while still doweling through structural wood (not plywood). A 12" dowel with a 1/2" to 3/4" diameter is sufficient to anchor the bucks to the bales. A layer of plaster's lath around the edges further strengthens the attachment.
No matter what design and anchoring you choose, be sure to know what it will be before you start building. As in any aspect of construction, the more you know before you start, the better!
Happy Baling!
-Andrew Morrison