Understanding the Basic Terminology
The first thing you need to know about the subject is the basic terminology. That would be the words and phrases that are used in general conversations about roof pitches. Phrases like “four and twelve” or “six in twelve” that are used to denote the the actual rake of a roof. Roofers and carpenters say “rake”, not “slope.”
The Terms that Denote Rake or Pitch
Roof pitches are denoted by the amount of vertical rise they have for every twelve inches of lateral measurement. This means that a roof that is 4 inches higher then it was 12 inches back, measuring on a level plane, is a 4 & twelve roof. A roof that rises six inches every twelve level inches, is described as a 6 and 12 roof.
What Goes into Deciding on Roof Pitches
So then what goes into deciding what the pitch will be on any given home? The answer that question is many things can factor into this type of decision, and of course one of the most obvious is looks. That is that certain roof pitches seem to fit certain home design styles better than others.
Limitations on the Height and Rake of a Roof
There are always some limitations though, and the most daunting one is height. That is the tall, steep roofs are difficult and expensive to work on. They’re dangerous, work is slow, and taller roofs have more square footage. So all these things combine to convince most people still in the design phase to stay with a more reasonably raked roof.
A 6 & 12 is the Steepest Roof You Can Walk on
As matter of course, a 6 & 12 roof is about as steep as you can go, and still be able to walk on it unassisted. Move up to an 8 & 12 roof, and now workers require toe boards to walk across it, and roofing materials are difficult to store on it. A 12 & 12 roof in fact has a 45º angle, requires extensive safety equipment, and the work pace is literally slowed to a “crawl”.