Door and Window Bucks

There are as many ways of making door and window bucks as there are bale builders. Your design will have to take into account several factors.

Choice of Finish

How you want your building to look will be the biggest determining factor in the design of your bucks. Narrow bucks will allow for significant rounding or carving around windows and doors. Full-width bucks will result in squared openings, typically finished in wood. You can combine different widths for the top, the sides, and the sill to create different appearances. This is a place to be creative!

Size of Opening

Because both post and beam and load-bearing bale walls use some form of heavy beam at the top of the wall, most rough bucks need only be strong enough to handle the weight of the bales that rest on them. Structural loads from the roof will be carried into the wall via the beam or top plate (which can be beefed up over wide openings).

Therefore, heavyweight lintels are usually not required over the windows and doors, and small dimension lumber can be used. But in the case of larger openings (greater than four feet) it may be necessary to have a more substantial header on your rough frames.We often use a box beam in these situations.

Plaster Finish

The placement of your bucks will determine the finish of your plaster. Bucks set flush with the straw will be covered witii plaster, and the plaster itself will use the installed window or door as a stop. Bucks set % to 1 inch beyond the face of the straw will themselves act as plaster stops, leaving an exposed wooden face for attaching trim.

Moisture Control

Your rough buck can play an important role in moisture control. Bottom sills that slope downward a few degrees will help to shed water. Bottom sills that protrude beyond the face of the bales by two inches or more can act as a drip edge if a saw kerf is cut on the underside. Gluing or caulking all the joints in the buck will help stop water leaks from entering the bale walls. The bucks can provide attachment points for whatever flashings you decide to use.

12.5a - e: A buck must be designed that will create the kind of window opening you want.

Combinations of flat and rounded elements will give different effects. The key is to ensure that upper and lower edges are well sealed and flashed against leaks, since this is the most vulnerable point in your wall

12.5a

12.5a

12.5c

12.5c

12.6b

12.6a

Positioning in the Wall One of the most common failure points for straw bale walls in wet and northern climates is below the window openings. Why? Too many builders set the window bucks back in the wall

12.6b

12.6a

12.6a - b: If the sills for a rough buck are notched into the uprights on the inside and front edges, then glued or caulked into the grooves, the rough bucks themselves become an excellent defense against moisture penetration. Give the rough sills a slight slope downward to the outside, allow them to extend well beyond the plaster and cut a groove on the underside to act as a drip kerf.

12.7b

12.7a

12.7b

12.7a

12.7a - b: A beautiful arched window opening requires proper detailing in your plans, and in execution. The framework, the straw and the mesh must all come together to create the desired effect.

to achieve that southwestern look of the rounded plaster sill. This is a bad idea in places where it rains and snows! Setting bucks and windows to the outside of the wall (along with a good flashing strategy) helps to ensure that water running down windows is shed away from the wall, not ducted into it. It also gives snow nowhere to accumulate. Only if a window is extremely well protected by a porch or significant roof overhang should the window be set into the wall. The best strategy is to keep the window to the outside of the wall and save the wide sill for the interior. Door frames have more latitude, since there is no bale wall beneath. Be aware, however, that if the door frame is set in partially or fully, that water will need to be kept out of the junction at the base of the wall with flashing and/or caulking.

Lumber for rough frames is usually 2-by-6, and where sheet lumber is used, it is typically Oriented Strand Board (OSB). The frames must be built to be strong enough to handle the rigors of a bale raising, which includes the use of some temporary cross-bracing to keep them square. The rough frame bucks installed in the bale wall will provide a place to attach the actual windows and doors. Design and construction of the rough frame bucks are open to a certain amount of improvisation by the builder as long as the above principles are adhered to.

Some builders make floating rough window bucks which sit on the appropriate course of bales. Others prefer secured bucks, which have legs that are attached to the foundation or the curb rails. We prefer bucks with legs, since they can be put in place prior to the bale raising (i.e., not positioned at the whim of the bale stackers!) and are easier to keep securely in position through the bale raising and prior to plastering.

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