Complex cut & stack from pre-cut package
As my crew and I took on more complex framing projects, I found the roof framing was bogging us down. Walls and ceilings would go up quickly, then things would grind to slow-mo at the complicated cut-up roof. I began to focus on minimizing roof framing time – a challenge on the complex multi-hipped roofs we were building.
After a lot of frustration, and a lot of analysis, I resolved to: A) pre-cut the roof in its entirety; and B) begin cutting the roof on day one. The layout lines were snapped, then measurements were taken for cutting the roof. While the rest of the crew framed the house, I cut the roof.
More than one naysayer dropped by to question my methodology, and my sanity! I recall lines like “putting the cart before the horse”, and “why are you cutting a roof when you don’t have a house yet?” Despite dire predictions to the contrary, I knew that as long as my crew built the house as it was snapped on the slab, my roof would fit.
The entire roof was mapped out on a piece of graph paper, which became my grocery list for cutting the whole package. In a sense, this is similar to what a truss manufacturer does – based on the blueprint dimensions, he builds the roof’s composite parts. Once cut, each jack rafter had starter nails placed at the top, which were used to hang the shorter ones from the top plate, and made nailing in place quick and easy. The rafters were stacked neatly, and marked for location. Each hip was divided into “quadrants”, meaning the set of jack rafters up one side of the hip.
One important key to my system was that layout was pulled in from each corner (not from the center out), so the jack rafters always followed a tidy – and identical – layout at the hip, and any layout adjustments needed were made somewhere in the middle of the wall. By doing this, the jack rafters could be figured and cut from day one – all that was needed was the roof pitch and the rafter spacing. Rafter and joist placement was critical, so layout was marked carefully on the top plate using the roof diagram.
The defining members – the hips, valleys, and ridges – went up first (with a few commons to hold the ridge in place). Once the framework was up, and checked visually to make sure it all planed in properly, the “fill” began, meaning jack and common rafters.
Doing it this way forced me to take extra care, and a little extra time, in figuring and measuring. I couldn’t cut a piece then put it in place to see if it fit – it just had to be right the first time. My tactic paid off in spades, because while figuring and cutting was a one-man job, the whole crew was involved in stacking the roof.
The actual “stack” portion of this cut-and-stack went quickly – the bulk of the roof was up in a day. Pre-cutting really minimized the stand-around time that used to occur while I’d scratch my head and try to figure the tricky cuts as the roof was going up. The crew enjoyed the project more, and the bottom line got healthier, which means I enjoyed the project more, too. And the client? – well, we all know, to the client, faster is better.
The roof pitch on this particular house was 5:12, with a 24” overhang, square-cut fascia, and 24” o.c. layout. The house design, 2300 sq. ft. not including garage and patio, was from a blueprint given us by Metco homes, the builder.
ALL JACKED UP In this picture, the defining members are up, and now the commons and jack rafters quickly fill in the remainder of the roof. This is where the framers really are having fun. Layout is marked on the wall, but where the jack rafters meet the hip there is no layout to follow. Instead, there is a string line pulled taut along the top center of the hip. When they're nailed in their proper place, that string line remains in the center of the hip. If they're off even a little, the string line will tell - and usually just a whack or two on the opposing jack rafter will put everything right again!
THE RAFTER MATH U LOVE First the entire roof was mapped out and each piece figured, using an inexpensive trig calculator. While at first appearing like a puzzling array of convoluted lines, the run of each piece is actually pretty simple math. Then, converting to theoretical length is not difficult using a standard trig calculator. If you use a proprietary construction calculator, you avoid the step of converting decimals to fractions of an inch. We didn't have Google Sketchup available then, but today you can bet I'd be using it to check my measurements! The adjustments for compensating for material thickness are made when cutting. Height-above-plate is a key measurement to have in mind at all times during the roof cutting.
PUT 'EM IN THEIR PLACE Every single rafter, ridge, hip and valley was cut and organized in numbered stacks, to show where they go. As with trusses, a mixup here can create a lot of headaches at assembly time! On the day the roof was stacked out, each piece of the giant puzzle was spread around the house in its relative position
DOWN IN THE VALLEY & UP ON THE RIDGE The defining members go up first - i.e. ridges, hips and valleys. This is probably the most significant juncture of the process (picture Charlie Brown in the infield, standing under a pop-fly, saying "I'm either going to be the hero or the goat..."). If the roof cutter has done his work well, everything will fit and plane in as it should. Any errors will become quickly manifest at this point!
THE PROOF IS IN THE PUDDIN'! Here is the completed roof, as it appears today. The streamlined low profile of the hip roof, with the wide stuccoed eaves, shows the Prairie influence of Frank Lloyd Wright. One advantage of a cut and stack roof over a truss roof is the increase in useable attic space. You can see more than a hundred photos of this job at http://eyemagination.smugmug.com/gallery/9191786_rXjWH#613456430_sxbd3