BuildMeter guide · Structures & Carpentry
Roof Cricket and Saddle Planning Guide
Understand cricket geometry, membrane area and critical curb-flashing transitions.
Direct answer
What to know first
A roof cricket diverts water around a wide curb or chimney. Its dimensions, minimum slope, membrane laps and terminations must be coordinated with the roof system; area calculations support takeoff but do not design the drainage detail.
Open Roof Cricket Area CalculatorPlanning workflow
- Measure the actual project geometry rather than relying on nominal dimensions.
- Separate open-field quantities from corners, openings, terminations and transitions.
- Use the selected manufacturer or approved detail to set spacing, laps, coverage or support rules.
- Apply a transparent allowance for cuts, damage and layout changes.
- Round to full purchasable packages or stock lengths and verify availability.
Worked example
Use the cricket's actual width, run and slope to calculate surface area and flashing/membrane lengths separately. Do not convert cricket area directly into valley or edge-flashing quantity; those are linear details.
Decision table
| Decision | Verify | Why it matters |
|---|---|---|
| Measured dimensions | Site measurements and drawings | Nominal dimensions can misstate the actual takeoff. |
| Installation rule | Product data and approved detail | Spacing, laps and coverage vary by system. |
| Allowance | Complexity, cuts and damage risk | Detailed work needs more waste than open runs. |
| Package rounding | Supplier stock and usable coverage | Projects purchase full pieces, rolls or containers. |
Common failures
- Using nominal package coverage without deducting overlaps or cut losses.
- Applying one universal spacing or detail to every product.
- Ignoring corners, openings, end conditions and transitions.
- Rounding before all project areas are combined.
- Treating a material takeoff as a substitute for design or code review.
Professional boundary
A roof cricket diverts water around a wide curb or chimney. Its dimensions, minimum slope, membrane laps and terminations must be coordinated with the roof system; area calculations support takeoff but do not design the drainage detail.
Use the calculator to compare cricket geometry and covering area. Drainage performance, framing and flashing integration must be resolved in the roof detail, especially behind wide chimneys or curbs.
Final field verification
Before using the roof cricket planning estimate as a purchase order, walk the project and compare the calculated scope with the installed conditions. Measure every roof plane, intersection, eave, ridge and penetration from the actual structure rather than a plan alone. Photograph or sketch unusual details and keep the measurements with the estimate so another person can understand how the quantity was produced.
- Check the roofing manufacturer instructions, local wind exposure and required laps before converting length into purchase quantities.
- Coordinate ventilation and water-shedding details so one component does not block drainage or create a concealed moisture path.
- Round only after all measured sections have been combined; rounding every small section independently can materially overstate the total.
- Recheck units, package coverage and the number of full stock lengths or containers required before checkout.