Window and Door Bucks in a Straw Bale Load Bearing House
Designing Strong Openings in a Straw Bale Load Bearing Structure
When building a straw bale load bearing house, few framing components matter more than your window and door bucks. These framed openings do more than hold your windows and doors—they create structural consistency, help anchor your walls, and make plastering easier and more durable.
So before you start stacking bales, let’s walk through the key decisions that will shape how your bucks perform—and how smoothly the install will go.
🧱 What Are Window and Door Bucks?
In natural building, “bucks” are the wooden frames built into straw bale walls to hold windows and doors. In a straw bale load bearing structure—where the bales carry the weight of the roof—these bucks also act as anchoring points, load distributors, and plaster edge protection.
📐 Key Design Questions to Answer First
Before you pick up a single 2x4, get clear on these three questions:
What size wood should I use?
What style or shape makes the most sense?
How will I anchor the bucks to the bales and wall system?
These choices affect everything from structural integrity to plaster performance—and your comfort inside the space.
✅ Flat vs. Angled Bucks: Choose Based on Function
Start by deciding the utility of the space around your window.
Flat Bucks
Best for windows used as seating areas or ledges
Provide clean, straight lines for trim
Easier to build and install
Angled (Flared) Bucks
Great for maximizing natural light
Help visually open up smaller rooms
Require more precision in cutting and framing
Pro Tip: Use a consistent style across all openings for a unified look—doors and windows alike.
🔨 Material Choice: Plywood + Dimensional Lumber
For most of my bucks—angled or flat—I use plywood sides framed into the structure. This gives two major benefits:
Improved nailing surfaces for mesh or lath
Reduced need for excessive dimensional lumber
Plywood extensions offer both efficiency and versatility, especially when working with varying wall depths.
📏 Anchoring the Bucks: Bigger Members, Better Grip
The depth of your wood matters more than you might think.
Using larger members—like 2x10s instead of 2x4s—lets you:
Drive longer dowels deeper into the bale for a stronger mechanical connection
Ensure dowels pass through solid wood, not just plywood
Anchor bucks more securely for long-term performance
For most straw bale load bearing builds, a 12-inch dowel (½" to ¾" diameter) is ideal. Add a layer of plaster lath around the perimeter to further lock the system together.
⚠️ Plan First, Build Better
As with all aspects of natural building, the more planning you do upfront, the fewer surprises you’ll face during construction. Your window and door buck design should be part of your earliest framing decisions—not something you figure out as you go.
Want to Learn More About Building a Straw Bale Load Bearing Home?
From buck framing to plaster prep and beyond, learn with our How-to Bale Building video course, hosted by the founder of the Strawbale.com Community, Andrew Morrison. It will walk you through what you need to know as you are dreaming of creating your own sustainable, beautiful straw bale home with an entire series dedicated to straw bale load bearing construction techniques.
Updated: May 16, 2025
