Question:  What is meant by the pitch of a roof rafter?

Answer:  The pitch of a truss is usually expressed by a number like 5/12.  The first number refers to how many inches the rafter rises per every twelve inches of run.  Thus a five twelve pitch roof rafter rises five inches in height for every twelve inches of width.  Knowing this number makes it easy for the carpenter to mark his rafters by using his framing square and a pencil.  When my dad taught me to mark rafters almost all roofs were a 5/12 or a 4/12.  This was for a ranch or standard two stories.  The higher the pitch roof the more expensive a home is to build.

Don Jason

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