MEASUREMENTS AND PURCHASE DECISIONS
Compare ridge cap physical and exposed length.
Why is exposed length the correct increment after the first cap?
Use the matching calculator
Use this decision sequence
- Use the measured length of each separate ridge run.
- Read physical piece length and the supplied overlap.
- Give the first cap its full length; use exposed length for each following cap.
- Keep special end pieces and intersections outside the straight-run count.
Keep the quantities distinct
| Quantity or assumption | How to use it |
|---|---|
| Physical cap length | The source piece dimension. |
| Exposed increment | Physical length minus specified overlap. |
| Separate run | Begins again with one full first piece. |
Worked comparison
A 5 m run with 1 m caps and 0.10 m overlap needs 1 + ceil((5−1)/0.90) = 6 caps. Five caps would cover only 4.6 m under the supplied overlap.
Check before using the estimate
Overlaps must come from the selected roof specification; the example is not an installation recommendation.
All dimensions, product properties, prices and specifications in this example are illustrative arithmetic inputs. Use the values from your measured plan, selected product data sheet and supplier quote. This guide does not choose construction specifications or certify safety.
Calculation and scope checked 2026-10-04. Methods and scope.