Cabin Chronicles Pt. 5: Roof Frame

by Robert Maxwell

This is the fifth part of "The Cabin Chronicles", the story of how I built my own home in the woods. For part 4, click here.

I was eager to start framing the roof of the cabin, but first I had to decide on the size and structure of my upstairs floor. I knew I wanted a loft of some sort, both for storage and additional floorspace. I also knew I wanted visible wood on the downstairs ceiling, so I opted for heavy, 6x8-inch rough-sawn beams rather than traditional floor joists designed to be concealed by drywall. I've always liked the look of heavy timber, and exposed ceiling beams would give me the chance to enjoy it every day. I had the beams custom cut at a local sawmill (most people don't order their timbers super thick and rough sawn, even though they all start off that way.) When the beams arrived I knew I'd need help lifting them onto my wall frames. Dad and I got a terrific shoulder workout heaving the 16 foot giants up, one side at a time, until they were all balanced on top of the walls, spanning them from north to south. Seven beams spaced approximately 2 feet apart. Enough area to form a good sized floor, while leaving the front third or so of the cabin open, so I could enjoy a cathedral ceiling effect when the roof was finished. It was already getting dark as I clambered up a ladder and onto the top plate of the wall, a long-bitted drill, hammer, and handful of 12-inch spikes in my tool belt. I've never been bothered by heights, which was lucky for me since I was balancing on a 5.5-inch board with an 8 foot drop on one side and an 11 foot drop on the other. My mission was to drill two holes in each end of all the beams, then drive the 12 inch spikes through the holes and into the wall frame, fastening the beams down. It took the better part of an hour to finish the job, and the sun had well and truly set when I climbed down the ladder. I was excited, knowing the time had finally come to frame the roof. I’m not sure why this step excited me more than others, except that I had the idea the roof would turn my box-looking construction project into a thing of beauty. I wasn't wrong, but once again I underestimated the work ahead. 


Throughout my cabin building journey, my dad was a huge help. Not only did he lend a hand during difficult stages of construction, he also gave me, little by little, the knowledge I needed to build. He never tried to teach me too much at once, knowing trying to process and prepare for several steps in advance would leave me feeling overwhelmed and discouraged. When it came time to frame my roof, his wisdom and experience came in handy yet again. I thought trusses were the way to go. The factory-assembled triangles seemed like they'd go up quickly and easily, without any of the complicated calculations and angular cuts I was sure rafters would involve. At the time, I saw no reason to even consider rafters, but Dad did. "Don't use trusses, Robert", he told me kindly. "Your place is small and you want to maximize usable space. Trusses will make your upstairs pretty much unusable, except as a storage space." I didn't relish the challenge of making and installing rafters, but I certainly didn't want my upstairs space clogged with cross braces, so I took Dad's advice and ordered lumber for rafters. The first step was deciding on the pitch of my roof. I knew from the beginning I wanted a tall, steep, old-fashioned looking roof, not one of the modern, shallow roofs that go up easily but transform potentially nice houses into cookie cutter bungalows. I settled on a nice, classic 12/12 pitch which meant the angle on the roof would be 90 degrees. This meant my rafters would meet the ridge board at the peak of the roof at 45 degrees, and the bottom of all the rafters, known as "rafter tails" would be the same. Angle wasn't the only parameter. I also needed to determine rafter length plus location of the "seat cut" – a notch that allows rafters to sit atop a wall. Rafter length is crucial, because it determines how much roof overhang you have beyond your walls and has a huge impact on how a building looks. Too much or too little overhang is like a bad haircut that never goes away. I knew most builders would have considered my concern over looks obsessive, but I didn't mind. I'd never understood why so many houses get slapped up in a few weeks with hardly a thought given to aesthetics. I had already invested lots of time and money in the cabin, so I wanted to be sure it wouldn't be an eyesore. 


With Dad's help, I temporarily installed the ridge board with some vertical braces screwed to the wall sheathing. I figured the only way to install rafters was the have the ridge board already in its final location, so the tops of the rafters have something to rest against. With this done, I did some careful measuring and cutting, trying to create my first rafter, which I'd use as a pattern to cut all the others, since in theory they should all be the same. That first rafter didn't pan out. I climbed up the roof and held it in place, and saw immediately that the length was right but the seat cut was too high. On my next attempt it was too low. My third rafter was right on the money, and I remember a strong sense of pride and accomplishment washing over me as a I held it in place on the building and posed for a photo snapped by my dad. A day later I had 36 identical rafters cut, and was well on my way to having a roof frame. Using my ridge board as a reference, I was able to install all the rafters at identical height, forming the base on which I'd install roof sheathing later. I quickly learned some important tricks, like always orienting rafters with the "bow" or upward swell facing upwards. Not all lumber has a bow, but many boards do, even if it's just a small one. Orienting these bows upwards insured the sheathing boards would be in full, firm contact with the rafters. Orienting a bow down meant there'd be ugly gaps between rafter and sheathing, and the whole geometry of the roof would be compromised. Within a day I had all the rafters installed. I stepped back to admire the cabin. It felt better now to call it "the cabin". Even though I'd been calling it that since it was clearing in the forest, now, for the first time, it actually looked like one. I was still a long way from the finish line (much longer than I thought), but for the first time I felt with deep satisfaction that the end was in sight.