Crafting a Custom Radius Beam and Shed Roof for a Front Porch Entry
(This is the tenth and final in a 10 part series. Credit: Akribis Leather. Luke Riemer, owner, was the framing contractor we hired for our build. The project consisted of a carriage house, garage extension with suite above, and renovation/expansion of the existing residence. All 3 phases of the project had some timber framing elements. Text below is a cleaned up transcript of the video above)
When it comes to home construction, small details can make a big difference. On this project, we faced a challenge at the front entry: a small shed roof had no supporting beam, and the beam that was ordered was oversized, which would have reduced headroom. The solution? Craft a custom radius beam to maintain structural integrity while preserving space. Here’s how it all came together.
Identifying the Challenge
The front entry of the house featured a squat, low ceiling under a shed roof. A large, chunky beam was initially ordered to match the rest of the home’s timber work, but it would have cut significantly into the headroom.
To solve this, we decided to cut a radius in a finished beam, allowing it to support the roof while maximizing clearance.
Step 1: Preparing the Beam
Before making any cuts, careful planning was essential:
- A plywood template was created to map out the radius.
- The radius ended about 2½–3 inches inside the post, providing room for adjustment.
- The beam would be cut with a chainsaw, then finished with a planer, belt sander, and router to restore the chamfered edges.
Support blocks were bolted at the ends of the beam to prevent blowout when cutting. Reference lines were squared on the beam for precision.
Step 2: Cutting and Shaping
With the template in place, we carefully cut the beam along the radius:
- Chainsaw: Roughly followed the template while staying ¼ inch from the line.
- Planer: Removed the bulk of the rough material and shaped the curve.
- Belt Sander: Smoothed the surface and refined the curve.
- Chamfering: Added a 45° chamfer on the edges with a router, intentionally cutting in the opposite direction of the grain to avoid tear-out.
To ensure a flawless finish:
- Sanded across the grain first with 50–60 grit sandpaper to remove rough spots.
- Finished along the grain for a smooth surface with no scratch marks, ready for staining.
The result was a perfectly curved beam that preserved headroom while matching the home’s aesthetic.
Step 3: Planning the Shed Roof
Next, we designed a small shed roof over the beam. The roof was simple but precise:
- Pitch: 2/12 (a gentle slope)
- Overhang: 1 foot all around
Using the mockup and math:
- Total span from beam face to subfascia: 60 inches
- Subtract ledger and subfascia: 57 inches
- Rise (using 2/12 pitch): 57 × 0.1666 ≈ 9.5 inches
- Diagonal (using Pythagoras): √(57² + 9.5²) ≈ 57.786 inches
This allowed for an accurate bird’s mouth cut to seat the roof correctly on the beam.
Step 4: Installing the Beam and Roof
Once the radius beam was cut, shaped, and ready for staining, it was installed at the front entry. The shed roof followed, fitted precisely over the beam. The result is a seamless, structurally sound entryway that maintains headroom while complementing the overall timber aesthetic of the home.
Reflections on the Project
This project was a fantastic opportunity to explore a variety of building techniques:
- Working on slabs and framed floors
- Hand-framed roofs and trusses
- Timber work, including arches and custom details
It showcased the combination of precision craftsmanship and practical problem-solving.
Key Takeaways
- Planning is everything: Templates and reference lines ensure accuracy.
- Support your material: Use blocks to prevent blowout when cutting curves.
- Work with the grain carefully: Sand across the grain first, then finish along it for a smooth surface.
- Math matters: Simple calculations ensure your roof fits perfectly.
- Small details count: A radius beam can make a huge difference in functionality and aesthetics.
Conclusion
With the radius beam in place and the shed roof installed, the front entry is complete. This project highlights how careful planning, precise cutting, and thoughtful design can transform a simple architectural challenge into a visually stunning and functional feature.
It’s been a rewarding journey, and it’s always a pleasure to share the process with others who appreciate the art and craft of construction.