Building The Perfect Cabin Roof Part 1 of 5

Here’s how to build the perfect ridge beam every time!

Simplicity is the ultimate sophistication. ~ Leonardo da Vinci

Whether your building an off grid cabin, tiny house, or a shed in the back yard there’s a 100% chance you’ll be putting a roof on it and its got to last for decades.

Wouldn’t it be nice if the roof was just a simple quick design, build and poof.

Let’s face it, not everyone enjoys being one or two storeys off the ground, holding a heavy wooden beam and swinging a hammer

I know I don’t!

So.. I’m here to make it really, REALLY easy for you (and for me).

That’s why we started with the ridge beam and we built it in small, easy to handle segments.

Most Roof Designs

Unfortunately, most common rafter and truss designs used today are not easy to build and even more cumbersome to install. They can have complex angles to cut, involving math and measurements that some of us would much rather do without.

They can be heavy to hoist if you’re working solo, or with just one other person, in a remote location. They also have some real drawbacks that can adversely put undo stress on your structure even when built properly.

All that aside, we feel we’ve cracked the code on building rafters and found the perfect design that exceeds the classic rafter design and will provide a long lasting, sturdy and secure structure for your roof. If you haven’t yet gone through our Ultimate Roof & Rafter Guide have a breeze through it to become familiar with roofing terminology and designs.

Our Rafter Design

Right off the bat you might not spot the difference between our rafter (below)…

… and that of the common rafter (below), but you soon will.

We personally haven’t seen the rafter design we use on any other cabins. However, that’s something we hope to remedy after we’ve explained all of the benefits of its design.

The Typical Common Rafter

In typical frame construction a birdsmouth joint (or bird’s beak cut) is a wood-working joint generally used to connect a rafter to the top plate of its supporting wall. This cut is used at the bottom while the top of the rafter is butted up again the side of the ridge beam/board.

Rafter Thrust

In typical rafter construction, outward “rafter thrust” is compensated for by using rafter ties and collar ties but is not eliminated.

TimberToolbox has a great calculator for rafter thrust and you can check it out here.

Our cabin roof has three sloped surfaces (seen below) which I’ll be referring to in this and future posts.

1. The main rafters on the rear of the cabin.
2. The main rafters on the front of the  cabin
3. The front deck rafters.

Our Rafter Design

In our rear rafter design, the birdsmouth cut is at both the top and bottom so that the entire weight is carried by the supporting wall as well as the ridge beam (see below).

The front main rafter also has a birdsmouth cut at the top only. The bottom of the rafter sits directly on top of the wall top plate (see below). There is no birdsmouth made here as there is no overhang required. the bottoms of thee rafter will be hidden inside the front deck roof.

Lastly, the deck rafters have a birdsmouth at the bottom only which sits on top of a ridge beam (see below).

The top of these sit on top of a purlin and are nailed into the main rafters (see below).