We require from buildings two kinds of goodness:
first, the doing their practical duty well:
then that they be graceful and pleasing in doing it.
– John Ruskin, draughtsman and watercolorist, 1819 – 1900
There are many ways to build a roof, but when you want to create usable, beautiful space underneath that roof in a small building, you don’t have a whole lot to think about. Steeply pitched rafters are the traditional way to frame a cabin roof, and that’s what our design uses here. Both sides are sloped 45º from horizontal, making this is what’s called a “12/12 pitch” in carpenter talk. This means there’s 12” of vertical rise of the roof surface for every 12” of horizontal run, creating a 90º angle at the peak. The geometry is simple, yet the shape looks great and there’s usable space underneath for the loft. Climbing and working on a roof this steep is more challenging than shallow designs, but the hassles of the angle is well-worth the beauty, the longer shingle life and the additional floor area.
The parts of your cabin that form the slope of your roof are called rafters, and cutting them accurately will be the most precise part of building your cabin. That said, you can relax. If you tackle the job the way I explain, checking and verifying your results as you go, you’ll easily succeed – even if you’ve never cut rafters before.
In This Section...
Preparing for Rafters
The first step towards making accurate rafters is to take a look at the 3D plan to see what you’re shooting for.
Installing Loft Beams
UNDERSTANDING THE LOFT BEAMS
Before you cut and raise your rafters, install the loft floor beams. These tie the side walls together, while also letting you set up a loft floor on which to work later, while the rafters go up.
Cutting Rafters & Marking the Ridge Board
CUTTING RAFTERS & MARKING THE RIDGE BOARD
Following the pattern on the plans, cut one identical pair of rafters, and no more. Although they might fit just right on your cabin, it always pays to double-check before you make all the rafters you need.
Raising the Rafters and Ridge Board
RAISING THE RAFTERS & RIDGE BOARD
Here’s a detailed look at the process for raising the rafters and ridge board. Lay some temporary boards on the loft beams and open area of the cabin to walk on, then follow these steps:
Loft and Roof Board Installation
INSTALLING LOFT FLOOR & ROOF BOARDS
You’ll find it easier to install the roof boards if the loft floor is installed first, allowing you a place to walk around while hoisting roof boards aloft.
Working on a Steep Roof
WORKING SAFELY ON A STEEP ROOF
At 45º from horizontal, this roof is too steep to work on without some kind of support. Roof jacks offer the best option for staying safe and storing your tools while putting up roof sheathing now, and roof insulation, shingles and skylight later.