Common Rafter Length

Geometric common-rafter length from horizontal run and pitch (rise per 12). Optional overhang adds to run. No ridge or birdsmouth deduction.

Construction & Trades

Geometric common-rafter length from horizontal run and pitch (rise per 12). Optional overhang adds to run. No ridge or birdsmouth deduction.

App id: ROOF-02. Reference version 1.0.

How to fill it

Fill the inputs. The tool shows the outputs.

On the tool screen, Calc is the working sheet. Presets stores values you reuse. Reference is the formula, assumptions, and provenance below.

Formula

rise = run × pitch/12; L = √(run² + rise²)

Inputs

Name	Unit
Horizontal run	`ft`
Pitch (rise per 12)	`1`
Overhang (horizontal) (optional)	`in`

Outputs

Name	Unit
Rafter length (hero result)	`ft`
Rise	`ft`
Angle	`deg`
Total run	`ft`

Diagnose

Observations are context. They do not pass or fail a structure. See Diagnose.

When	Observation	Severity
`\|Pitch (rise per 12)\| ≥ 12`	Steep roof pitch	caution

Provenance

Pitch 6 means 6:12. Same slope primitive as GEOM-02.