Valley rafter calculator
Estimate valley geometry while keeping intersection and load review explicit.
What you enter
- Valley type (Overlay = over an existing roof)
- Horizontal run (in)
- Pitch rise (in / 12)
- Pitch run (in)
- Existing roof pitch rise (in / 12)
- Height from the truss peak to where the existing roof starts (in)
- Ridge board thickness (in)
- Ridge board depth (in)
- Sleeper board thickness (in)
- Sleeper board depth (in)
- Rafter spacing on center (in)
- Rafter thickness (in)
- First rafter center (blank = 0) (in)
- Ridge sits on the sleeper
- Show the sleeper angle to the ridge plane
Main results
- Valley rafter length
- Valley angle
- Intersection and load review note
What it follows
Plain geometry on the numbers you type; no building-code table is looked up. The result carries a note that the intersection and its loads still need review.
Every result is marked REVIEW REQUIRED. Illustrative project-planning values only; jurisdiction, species, grade, loads, wet service and current adopted tables require review. Do not use a result directly for permit, purchase, or field use.
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The calculator opens inside the designer, after you sign in.
Accounts are issued by the DeckAndShed team. There is no self-service sign-up.