The First Time on a Framing Square
Throughout the ages of building bastard roof system, the Chappell Universal Square provides the first comprehensive unequal pitched rafter tables that include the following values:
- Hip and Valley pitch in inches of rise per unit of run.
- Hip and Valley pitches in degrees.
- Difference in length of runs side A to side B.
- Length of Hip or Valley per unit of common run.
- Difference in length of jack purlins per unit of spacing.
- Top Cut of purlin.
- Difference in length of jack rafters per unit of spacing.
- Top Cut angle of jack rafters.
- Backing and bevel angles in degrees.
- Top Cut saw angles for jack rafters and purlins.
- Purlin/Frieze side face layout angle.
- Fascia miter angle.
- Housing angle of purlins to hip or valley.
- Side layout angle hip & valley to purlin header.
- Fascia/Frieze bevel angle for rafter tails cut at 90°.
Unequal Pitched Rafter Tables
The Chappell Universal Square Unequal Pitched Rafter Tables bring a new depth of knowledge to roof framing. Throughout most of western building history only the most experienced roof framers dared to tackle unequal pitched roof systems, and for good reason. It required builders to dig deeply into their bag of tricks—accompanied with a good measure head-scratching along the way. But the tricks provided only the most fundamental rotational angles and length ratios. The rest was left up to dead-reckoning and intuition.
This coveted knowledge, once reserved only for carpenters who had proven their mettle, and passed along only from master to apprentice for generations, is now at the fingertips of any aspiring builder in the Unequal Pitched Rafter Tables, deeply etched into the blade of the Chappell Universal Square.
They call’em Bastard Roofs for Good Reason
Builders of every ilk and region on the planet lovingly refer to unequal pitched roof systems as bastard roofs. One reason, is there have never really been any rules-of-the-road laid down to deal with these irregular roofs. So they’ve been seem as pain in the ass to most builders throughout the ages. Every carpenter found their own way to get the job done, and that was that. The Unequal Pitched Rafter Tables on the Chappell Universal Square marks the first true innovation in the approach to building unequal pitched roof framing, and the first real rules of the road to follow.
Unequal pitched roof systems are lovingly referred to as bastard roofs by builders of every ilk and region on the planet—for good reason. This was mostly, due to the fact that there have never been any real rules-of-the-road laid down. Every carpenter found their own way to get the job done, and that was that. The Unequal Pitched Rafter Tables on the Chappell Universal Square marks the first true innovation in the approach to building unequal pitched roof framing, and the first real rules of the road to follow.
Prior to the Chappell Universal Square
The clearest formal system for building bastard roofs was perfected by the French, called the French-Scribe-Rule System. This is based on the same essential lofting system used by boatbuilders to this day. This approach is absolute, and works brilliantly. But, it requires the builder to physically lift and position the full-scale timbers, one over another, above the footprint plan chalked onto the lofting room floor. The resulting crossover angles and lengths are marked or scribed, physically, in the same relationship and orientation they will have in the standing roof. This entails handling and moving the timbers several times, so by virtue of weight and logistics, this process essentially excludes a single person from carrying it out alone.
Patented Unequal Pitched Rafter Tables
The Chappell Universal Square’s patented Unequal Pitched Rafter Tables unlock the mystery of Bastard Roof Systems for the first time in building history. The revolutionary tables put a wealth of knowledge right in the palm of your hand by providing 17 key rotational angles for Unequal Pitches Roof Systems. This includes even the most complex and elusive Purlin/Frieze Side Cut, Facias Mitre Angles and Backing Angles for Unequal Pitched Roof Systems. No more dead-reckoning, no more head scratching, and no more lugging heavy timbers around your shop floor to set up the precise orientation.
No Batteries or Calculator Required
The only thing a would-be-roof-framer needs to master unequal pitched hip & valley roof framing—pro or DYI— is a Chappell Universal Square, a pencil, and a scrap piece of wood to scribble out simple math—addition and multiplication. This is all one needs to transform the unique values that are deeply etched into the square into angular ratios. These ratios can be applied directly to the square to directly mark perfect, accurate angular layout and cut angles. The data in the tables provides factors to determine member lengths and spacing reductions. All requiring only simple grade school math.
This is where the pencil and scrap piece of wood come into play. The base 10 decimal system allows fluid long-hand math simply scribbled on a scrap of wood. No frustrating fractions to convert EVER, and NO BATTERIES OR CALCULATOR REQUIRED.
Find your peace-of-mind by adding a Chappell Universal Square with Unequal Pitched Rafter Tables to your tool box. The only thing left to do is to get on with the work-at-hand of building your next roof system.
Chappell Universal Square—
Rebuilding America One Square at a Time.
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Check out our YOUTUBE Channel To learn more view our series of instructional videos. You will see just how easy it is to use the Chappell Universal Square to build your next Masterpiece.
Lear more about EQUAL PITCHED RAFTER TABLES
Check out the POLYGON RAFTER TABLES
Reviews from the Press
Never Sponsored Substack by Christopher Schwarz: The Chappell Universal Square
This Is Carpentry Review: The Chappell Square, A revolutionary approach to a commonly used tool
Home Fixated Review: Chappell Square Review – The Supercomputer of Framing Squares
JLC-Journal of Light Construction Review: Chappell Master Framer Square
SBE Builders by Sim Ayers: Chappell Master Framing Square Review